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PIC16F1509

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507 views384 pages

PIC16F1509

mcu

Uploaded by

Uzair Ahmed Chughtai

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PIC16(L)F1508/9

Data Sheet
20-Pin Flash, 8-Bit Microcontrollers
with nanoWatt XLP Technology

2011 Microchip Technology Inc.

Preliminary

DS41609A

Note the following details of the code protection feature on Microchip devices:

Microchip products meet the specification contained in their particular Microchip Data Sheet.

Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.

There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchips Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.

Microchip is willing to work with the customer who is concerned about the integrity of their code.

Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as unbreakable.

Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchips code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.

Information contained in this publication regarding device

applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyers risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights.

Trademarks
The Microchip name and logo, the Microchip logo, dsPIC,
KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART,
PIC32 logo, rfPIC and UNI/O are registered trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor,
MXDEV, MXLAB, SEEVAL and The Embedded Control
Solutions Company are registered trademarks of Microchip
Technology Incorporated in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, chipKIT,
chipKIT logo, CodeGuard, dsPICDEM, dsPICDEM.net,
dsPICworks, dsSPEAK, ECAN, ECONOMONITOR,
FanSense, HI-TIDE, In-Circuit Serial Programming, ICSP,
Mindi, MiWi, MPASM, MPLAB Certified logo, MPLIB,
MPLINK, mTouch, Omniscient Code Generation, PICC,
PICC-18, PICDEM, PICDEM.net, PICkit, PICtail, REAL ICE,
rfLAB, Select Mode, Total Endurance, TSHARC,
UniWinDriver, WiperLock and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
2011, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
ISBN: 978-1-61341-726-3
Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Companys quality system processes and procedures
are for its PIC MCUs and dsPIC DSCs, KEELOQ code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchips quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.

DS41609A-page 2

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
20-Pin Flash, 8-Bit Microcontrollers with nanoWatt XLP Technology
High-Performance RISC CPU:
C Compiler Optimized Architecture
Only 49 Instructions
Up to 14 Kbytes Linear Program Memory
Addressing
Up to 512 bytes Linear Data Memory Addressing
Operating Speed:
- DC 20 MHz clock input
- DC 200 ns instruction cycle
Interrupt Capability with Automatic Context
Saving
16-Level Deep Hardware Stack with Optional
Overflow/Underflow Reset
Direct, Indirect and Relative Addressing modes:
- Two full 16-bit File Select Registers (FSRs)
- FSRs can read program and data memory

Flexible Oscillator Structure:

16 MHz Internal Oscillator Block:
- Factory calibrated to 1%, typical
- Software selectable frequency range from
16 MHz to 31 kHz
31 kHz Low-Power Internal Oscillator
Three External Clock modes up to 20 MHz

Special Microcontroller Features:

Operating Voltage Range:
- 1.8V to 3.6V (PIC16LF1508/9)
- 2.3V to 5.5V (PIC16F1508/9)
Self-Programmable under Software Control
Power-on Reset (POR)
Power-up Timer (PWRT)
Programmable Low-Power Brown-Out Reset
(LPBOR)
Extended Watchdog Timer (WDT):
- Programmable period from 1 ms to 256s
Programmable Code Protection
In-Circuit Serial Programming (ICSP) via Two
Pins
Enhanced Low-Voltage Programming (LVP)
In-Circuit Debug (ICD) via two pins
Power-Saving Sleep mode:
- Low-Power Sleep mode
- Low-Power BOR (LPBOR)
Integrated Temperature Indicator
128 Bytes High-Endurance Flash
- 100,000 write Flash endurance (minimum)

2011 Microchip Technology Inc.

Extreme Low-Power Management

with nanoWatt XLP (PIC16LF1508/9):
Standby Current:
- 25 nA @ 1.8V, typical
Watchdog Timer Current:
- 300 nA @ 1.8V, typical
Operating Current:
- 30 A/MHz @ 1.8V, typical
Timer1 Oscillator Current:
- 600 nA @ 32 kHz, 1.8V, typical

Peripheral Features:
Analog-to-Digital Converter (ADC):
- 10-bit resolution
- 12 external channels
- 3 internal channels:
- Fixed Voltage Reference
- Digital-to-Analog Converter
- Temperature Indicator channel
- Auto acquisition capability
- Conversion available during Sleep
2 Comparators:
- Rail-to-rail inputs
- Power mode control
- Software controllable hysteresis
Voltage Reference module:
- Fixed Voltage Reference (FVR) with 1.024V,
2.048V and 4.096V output levels
- Up to 1 rail-to-rail resistive 5-bit DAC with
positive reference selection
18 I/O Pins (1 Input-only Pin):
- High current sink/source 25 mA/25 mA
- Individually programmable weak pull-ups
- Individually programmable
interrupt-on-change (IOC) pins
Timer0: 8-Bit Timer/Counter with 8-Bit
Programmable Prescaler
Enhanced Timer1:
- 16-bit timer/counter with prescaler
- External Gate Input mode
Timer2: 8-Bit Timer/Counter with 8-Bit Period
Register, Prescaler and Postscaler
Four 10-bit PWM modules
Master Synchronous Serial Port (MSSP) with SPI
and I2C with:
- 7-bit address masking
- SMBus/PMBus compatibility

Preliminary

DS41609A-page 3

PIC16(L)F1508/9
Peripheral Features (Continued):

Numerically Controlled Oscillator (NCO):

- 20-bit accumulator
- 16-bit increment
- True linear frequency control
- High-speed clock input
- Selectable Output modes
- Fixed Duty Cycle (FDC) mode
- Pulse Frequency (PF) mode
Complementary Waveform Generator (CWG):
- 8 selectable signal sources
- Selectable falling and rising edge dead-band
control
- Polarity control
- 4 auto-shutdown sources
- Multiple input sources: PWM, CLC, NCO

Enhanced Universal Synchronous Asynchronous

Receiver Transmitter (EUSART)
- RS-232, RS-485 and LIN compatible
- Auto-Baud Detect
- Auto-wake-up on Start
4 Configurable Logic Cell (CLC) modules:
- 16 selectable input source signals
- Four inputs per module
- Software control of combinational/sequential
logic/state/clock functions
- AND/OR/XOR/D Flop/D Latch/SR/JK
- External or internal inputs/outputs
- Operation while in Sleep

DS41609A-page 4

Preliminary

Debug(1)

XLP

PIC12(L)F1501 (1) 1024 64

6 4
1
1
2/1
4

1
2
PIC16(L)F1503 (2) 2048 128 12 8
2
1
2/1
4

1
1
2
PIC16(L)F1507 (3) 2048 128 18 12
2/1
4

1
2
PIC16(L)F1508 (4) 4096 256 18 12 2
1
2/1
4
1
1
1
4
PIC16(L)F1509 (4) 8192 512 18 12 2
1
2/1
4
1
1
1
4
Note 1: I - Debugging, Integrated on Chip; H - Debugging, Requires Debug Header.
2: One pin is input-only.
Data Sheet Index: (Unshaded devices are described in this document.)
1: Future Product
PIC12(L)F1501 Data Sheet, 8-Pin Flash, 8-bit Microcontrollers.
2: DS41607
PIC16(L)F1503 Data Sheet, 14-Pin Flash, 8-bit Microcontrollers.
3: DS41586
PIC16(L)F1507 Data Sheet, 20-Pin Flash, 8-bit Microcontrollers.
4: DS41609
PIC16(L)F1508/1509 Data Sheet, 20-Pin Flash, 8-bit Microcontrollers.

NCO

CLC

CWG

MSSP (I2C/SPI)

EUSART

PWM

Timers
(8/16-bit)

DAC

Comparators

10-bit ADC (ch)

I/Os(2)

Data SRAM
(bytes)

Program Memory
Flash (words)

Device

Data Sheet Index

PIC12(L)F1501/PIC16(F)L150X Family Types

1
1
1
1
1

H
H
H
I/H
I/H

Y
Y

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 1:

20-PIN PDIP, SOIC, SSOP PACKAGE DIAGRAM FOR PIC16(L)F1508/9

PDIP, SOIC, SSOP

VSS
RA0/ICSPDAT

RA4

3
4

RA1/ICSPCLK

MCLR/VPP/RA3

RA2

RC5

RC4

RC3

RC6

PIC16LF1508/9

RA5

PIC16F1508/9

VDD

RC0

RC1

RC2

RB4

RC7

RB5

RB7

RB6

Note: See Table 1 for location of all peripheral functions.

20-PIN QFN PACKAGE DIAGRAM FOR PIC16(L)F1508/9

VSS

VDD

RA5

RA4

QFN 4x4

RA0/ICSPDAT

FIGURE 2:

20 19 18 17 16
MCLR/VPP/RA3

RC5

RC4

RC3

RB6

RA1/ICSPCLK

RA2

RC0

RC1

RC2

9 10

RB4

RB5

RB7

RC7

RC6

PIC16F1508/9
PIC16LF1508/9

Note: See Table 1 for location of all peripheral functions.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 5

PIC16(L)F1508/9

RA1

AN1

VREF+

C1IN0C2IN0-

RA2

AN2

DACOUT2

C1OUT

T0CKI

RA3

RA4

AN3

RA5

RB4

RB5

RB6

RB7

IOC

ICSPDAT
ICDDAT

CLC4IN1

IOC

ICSPCLK
ICDCLK

CWG1FLT

CLC1(1)

PWM3

INT/
IOC

T1G(2)

SS(2)

CLC1IN0

IOC

MCLR
VPP

SOSCO
T1G(1)

IOC

CLKOUT
OSC2

SOSCI
T1CKI

NCO1CLK

IOC

CLKIN
OSC1

AN10

SDA/SDI

CLC3IN0

IOC

AN11

RX/DT

CLC4IN0

IOC

SCL/SCK

IOC

TX/CK

CLC3

IOC

RC0

AN4

C2IN+

CLC2

RC1

AN5

C1IN1C2IN1-

NCO1(1)

PWM4

RC2

AN6

C1IN2C2IN2-

RC3

AN7

C1IN3-

CLC2IN0

PWM2

RC4

C2OUT

CWG1B

CLC4
CLC2IN1

RC5

CWG1A

CLC1(2)

PWM1

CLC3IN1

MSSP

Basic

EUSART

C1IN+

Pull-up

Timers

DACOUT1

Interrupt

Comparator

AN0

PWM

Reference

CLC

A/D

NCO

20-Pin QFN

RA0

CWG

20-Pin PDIP/SOIC/SSOP

20-PIN ALLOCATION TABLE (PIC16(L)F1508/9)

I/O

TABLE 1:

(1)

(2)

RC6

AN8

RC7

AN9

SDO

CLC1IN1

VDD

VSS

1:
2:

Default location for peripheral pin function. Alternate location can be selected using the APFCON register.
Alternate location for peripheral pin function selected by the APFCON register.

VSS
Note

DS41609A-page 6

Preliminary

NCO1

2011 Microchip Technology Inc.

PIC16(L)F1508/9
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 9
2.0 Enhanced Mid-Range CPU ........................................................................................................................................................ 15
3.0 Memory Organization ................................................................................................................................................................. 17
4.0 Device Configuration .................................................................................................................................................................. 43
5.0 Oscillator Module (With Fail-Safe Clock Monitor)....................................................................................................................... 49
6.0 Resets ........................................................................................................................................................................................ 65
7.0 Interrupts .................................................................................................................................................................................... 73
8.0 Power-Down Mode (Sleep) ........................................................................................................................................................ 87
9.0 Watchdog Timer ......................................................................................................................................................................... 91
10.0 Flash Program Memory Control ................................................................................................................................................. 95
11.0 I/O Ports ................................................................................................................................................................................... 111
12.0 Interrupt-On-Change ................................................................................................................................................................ 125
13.0 Fixed Voltage Reference (FVR) ............................................................................................................................................... 131
14.0 Temperature Indicator Module ................................................................................................................................................. 133
15.0 Analog-to-Digital Converter (ADC) Module .............................................................................................................................. 135
16.0 Digital-to-Analog Converter (DAC) Module .............................................................................................................................. 149
17.0 Comparator Module.................................................................................................................................................................. 153
18.0 Timer0 Module ......................................................................................................................................................................... 163
19.0 Timer1 Module with Gate Control............................................................................................................................................. 167
20.0 Timer2 Module ......................................................................................................................................................................... 179
21.0 Master Synchronous Serial Port Module.................................................................................................................................. 183
22.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 237
23.0 Pulse Width Modulation (PWM) Module................................................................................................................................... 265
24.0 Configurable Logic Cell (CLC).................................................................................................................................................. 271
25.0 Numerically Controlled Oscillator (NCO) Module ..................................................................................................................... 287
26.0 Complementary Waveform Generator (CWG) Module ............................................................................................................ 297
27.0 In-Circuit Serial Programming (ICSP) ............................................................................................................................... 313
28.0 Instruction Set Summary .......................................................................................................................................................... 315
29.0 Electrical Specifications............................................................................................................................................................ 329
30.0 DC and AC Characteristics Graphs and Charts ....................................................................................................................... 357
31.0 Development Support............................................................................................................................................................... 359
32.0 Packaging Information.............................................................................................................................................................. 363
Appendix A: Data Sheet Revision History.......................................................................................................................................... 373
Index .................................................................................................................................................................................................. 375
The Microchip Web Site ..................................................................................................................................................................... 381
Customer Change Notification Service .............................................................................................................................................. 381
Customer Support .............................................................................................................................................................................. 381
Reader Response .............................................................................................................................................................................. 382
Product Identification System ............................................................................................................................................................ 383

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 7

PIC16(L)F1508/9
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and
enhanced as new volumes and updates are introduced.
If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via
E-mail at docerrors@microchip.com or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We
welcome your feedback.

Most Current Data Sheet

To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).

Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision
of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
Microchips Worldwide Web site; http://www.microchip.com
Your local Microchip sales office (see last page)
When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are
using.

Customer Notification System

DS41609A-page 8

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
1.0

DEVICE OVERVIEW

Reference Table 1-1 for peripherals available per

device.

The PIC16(L)F1508/9 are described within this data

sheet. They are available in 14-pin packages. Figure 1-1
shows a block diagram of the PIC16(L)F1508/9 devices.
Tables 1-2 shows the pinout descriptions.

PIC16LF1501

PIC16F1503

PIC16LF1503

PIC16F1507

PIC16LF1507

PIC16F1508/9

PIC16LF1508/9

DEVICE PERIPHERAL SUMMARY

PIC16F1501

TABLE 1-1:

Analog-to-Digital Converter (ADC)

Complementary Wave Generator (CWG)

Digital-to-Analog Converter (DAC)

Peripheral

Enhanced Universal
Synchronous/Asynchronous
Receiver/Transmitter (EUSART)
Fixed Voltage Reference (FVR)

Numerically Controlled Oscillator (NCO)

Temperature Indicator

Comparators
C1
C2
Configurable Logic Cell (CLC)
CLC1

CLC2

CLC3

CLC4

Master Synchronous Serial Ports

MSSP1

PWM Modules
PWM1

PWM2

PWM3

PWM4

Timer0

Timer1

Timer2

Timers

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 9

PIC16(L)F1508/9
FIGURE 1-1:

PIC16(L)F1508/9 BLOCK DIAGRAM

Program
Flash Memory
RAM

OSC2/CLKOUT

OSC1/CLKIN

Timing
Generation

PORTA
CPU

INTRC
Oscillator

PORTB

(Figure 2-1)
MCLR

EUSART

CLC1

Temp.
Indicator

Note

DS41609A-page 10

ADC
10-Bit

1:
2:

PORTC

CLC2

CLC3

FVR

CLC4

Timer0

Timer1

Timer2

CWG1

NCO1

PWM1

PWM2

PWM3

PWM4

MSSP1

DAC

See applicable chapters for more information on peripherals.

See Table 1-1 for peripherals available on specific devices.

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 1-2:

PIC16(L)F1508/9 PINOUT DESCRIPTION

Name
RA0/AN0/C1IN+/DACOUT1/
ICSPDAT/ICDDAT

RA1/AN1/CLC4IN1/VREF+/
C1IN0-/C2IN0-/ICSPCLK/
ICDCLK

RA2/AN2/C1OUT/DACOUT2/
T0CKI/INT/PWM3/CLC1(1)/
CWG1FLT

RA3/CLC1IN0/VPP/T1G(2)/SS(2)/
MCLR

RA4/AN3/SOSCO/
CLKOUT/T1G

RA5/CLKIN/T1CKI/NCO1CLK/
SOSCI

Function

Input
Type

RA0

TTL

AN0

Output
Type

Description

CMOS General purpose I/O.

A/D Channel input.

C1IN+

Comparator positive input.

DACOUT1

Digital-to-Analog Converter output.

ICSPDAT

CMOS ICSP Data I/O.

ICDDAT

CMOS In-Circuit Debug data.

RA1

TTL

CMOS General purpose I/O.

AN1

A/D Channel input.

CLC4IN1

Configurable Logic Cell source input.

VREF+

A/D Positive Voltage Reference input.

C1IN0-

Comparator negative input.

C2IN0-

Comparator negative input.

ICSPCLK

ICSP Programming Clock.

ICDCLK

In-Circuit Debug Clock.

RA2

AN2

C1OUT

DACOUT2

CMOS General purpose I/O.

A/D Channel input.

CMOS Comparator output.

Digital-to-Analog Converter output.

T0CKI

Timer0 clock input.

INT

External interrupt.

PWM3

CMOS PWM output.

CLC1

CMOS Configurable Logic Cell source output.

CWG1FLT

Complementary Waveform Generator Fault input.

RA3

TTL

General purpose input with IOC and WPU.

CLC1IN0

Configurable Logic Cell source input.

VPP

Programming voltage.

T1G

Timer1 Gate input.

Slave Select input.

MCLR

Master Clear with internal pull-up.

RA4

TTL

CMOS General purpose I/O.

AN3

SOSCO

XTAL

CLKOUT

T1G

A/D Channel input.

Secondary Oscillator Connection.

CMOS FOSC/4 output.

Timer1 Gate input.

RA5

TTL

CLKIN

CMOS

CMOS General purpose I/O.

T1CKI

Timer1 clock input.

NCO1CLK

Numerically Controlled Oscillator Clock source input.

SOSCI

XTAL

External clock input (EC mode).

Secondary Oscillator Connection.

Legend: AN = Analog input or output CMOS = CMOS compatible input or output

OD = Open Drain
TTL = TTL compatible input ST
= Schmitt Trigger input with CMOS levels I2C = Schmitt Trigger input with I2C
HV = High Voltage
XTAL = Crystal
levels
Note 1: Default location for peripheral pin function. Alternate location can be selected using the APFCON register.
2: Alternate location for peripheral pin function selected by the APFCON register.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 11

PIC16(L)F1508/9
TABLE 1-2:

PIC16(L)F1508/9 PINOUT DESCRIPTION (CONTINUED)

Name
RB4/AN10/CLC3IN0/SDA/SDI

RB5/AN11/CLC4IN0/RX/DT

RB6/SCL/SCK

RB7/CLC3/TX/CK

RC0/AN4/CLC2/C2IN+

RC1/AN5/C1IN1-/C2IN1-/PWM4/
NCO1(1)

RC2/AN6/C1IN2-/C2IN2-

RC3/AN7/C1IN3-/PWM2/
CLC2IN0

RC4/C2OUT/CLC2IN1/CLC4/
CWG1B

Function

Input
Type

RB4

TTL

Output
Type

Description

CMOS General purpose I/O.

AN10

A/D Channel input.

CLC3IN0

Configurable Logic Cell source input.

SDA

I2C

I2C data input/output.

SDI

CMOS

SPI data input.

RB5

TTL

AN11

CMOS General purpose I/O.

A/D Channel input.

CLC4IN0

Configurable Logic Cell source input.

USART asynchronous input.

CMOS USART synchronous data.

RB6

TTL

CMOS General purpose I/O.

SCL

I2C

SCK

RB7

TTL

CLC3

CMOS Configurable Logic Cell source output.

I2C clock.

CMOS SPI clock.

CMOS General purpose I/O.

CMOS USART asynchronous transmit.

CMOS USART synchronous clock.

RC0

TTL

CMOS General purpose I/O.

AN4

CLC2

C2IN+

RC1

TTL

AN5

A/D Channel input.

C1IN1-

Comparator negative input.

C2IN1-

Comparator negative input.

A/D Channel input.

CMOS Configurable Logic Cell source output.

Comparator positive input.

CMOS General purpose I/O.

PWM4

CMOS PWM output.

NCO1

CMOS Numerically Controlled Oscillator is source output.

RC2

TTL

AN6

A/D Channel input.

C1IN2-

Comparator negative input.

C2IN2-

Comparator negative input.

RC3

TTL

AN7

C1IN3-

PWM2

CLC2IN0

RC4

TTL

CMOS General purpose I/O.

A/D Channel input.

Comparator negative input.

CMOS PWM output.

Configurable Logic Cell source input.

CMOS General purpose I/O.

C2OUT

CLC2IN1

CMOS Comparator output.

CLC4

CMOS Configurable Logic Cell source output.

CWG1B

CMOS CWG complementary output.

Configurable Logic Cell source input.

Legend: AN = Analog input or output CMOS = CMOS compatible input or output

DS41609A-page 12

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 1-2:

PIC16(L)F1508/9 PINOUT DESCRIPTION (CONTINUED)

Name
RC5/PWM1/CLC1(2)/
CWG1A

RC6/AN8/NCO1(2)/CLC3IN1/
SS(1)

Function

Input
Type

RC5

TTL

Output
Type

Description

CMOS General purpose I/O.

PWM1

CMOS PWM output.

CLC1

CMOS Configurable Logic Cell source output.

CWG1A

CMOS CWG primary output.

RC6

TTL

CMOS General purpose I/O.

AN8

NCO1

CLC3IN1

Configurable Logic Cell source input.

Slave Select input.

RC7

TTL

AN9

A/D Channel input.

CLC1IN1

Configurable Logic Cell source input.

SDO

VDD

Power

Positive supply.

VSS

Power

Ground reference.

RC7/AN9/CLC1IN1/SDO

A/D Channel input.

CMOS Numerically Controlled Oscillator source output.

CMOS General purpose I/O.

CMOS SPI data output.

Legend: AN = Analog input or output CMOS = CMOS compatible input or output

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 13

PIC16(L)F1508/9
NOTES:

DS41609A-page 14

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
2.0

ENHANCED MID-RANGE CPU

This family of devices contain an enhanced mid-range

8-bit CPU core. The CPU has 49 instructions. Interrupt
capability includes automatic context saving. The
hardware stack is 16 levels deep and has Overflow and
Underflow Reset capability. Direct, Indirect, and
Relative addressing modes are available. Two File
Select Registers (FSRs) provide the ability to read
program and data memory.

Automatic Interrupt Context Saving

16-level Stack with Overflow and Underflow
File Select Registers
Instruction Set

2.1

Automatic Interrupt Context

Saving

During interrupts, certain registers are automatically

saved in Shadow registers and restored when returning
from the interrupt. This saves stack space and user
code. See Section 7.5 Automatic Context Saving,
for more information.

2.2

16-Level Stack with Overflow and

Underflow

These devices have an external stack memory 15 bits

wide and 16 words deep. A Stack Overflow or Underflow will set the appropriate bit (STKOVF or STKUNF)
in the PCON register, and if enabled will cause a software Reset. See section Section 3.4 Stack for more
details.

2.3

File Select Registers

There are two 16-bit File Select Registers (FSR). FSRs

can access all file registers and program memory,
which allows one Data Pointer for all memory. When an
FSR points to program memory, there is one additional
instruction cycle in instructions using INDF to allow the
data to be fetched. General purpose memory can now
also be addressed linearly, providing the ability to
access contiguous data larger than 80 bytes. There are
also new instructions to support the FSRs. See
Section 3.5 Indirect Addressing for more details.

2.4

Instruction Set

There are 49 instructions for the enhanced mid-range

CPU to support the features of the CPU. See
Section 28.0 Instruction Set Summary for more
details.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 15

PIC16(L)F1508/9
FIGURE 2-1:

CORE BLOCK DIAGRAM

Configuration

MUX

Flash
Program
Memory

Program
Bus

16-Level
8 Level Stack
Stack
(13-bit)
(15-bit)

Instruction
Instruction Reg
reg

Data Bus

Program Counter

RAM

Program Memory
Read (PMR)

RAM Addr

Addr MUX
Indirect
Addr
12
12

Direct Addr 7
5
BSR
FSR Reg
reg

FSR0reg
Reg
FSR
FSR1
Reg
FSR reg
15

STATUS Reg
reg
STATUS

8
3

CLKIN
CLKOUT

Instruction
Decodeand
&
Decode
Control
Timing
Generation

Internal
Oscillator
Block

DS41609A-page 16

MUX

Power-up
Timer
Power-on
Reset
Watchdog
Timer
Brown-out
Reset

VDD

ALU
8
W Reg

VSS

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
3.0

MEMORY ORGANIZATION

These devices contain the following types of memory:

Program Memory
- Configuration Words
- Device ID
- User ID
- Flash Program Memory
Data Memory
- Core Registers
- Special Function Registers
- General Purpose RAM
- Common RAM

TABLE 3-1:

The following features are associated with access and

control of program memory and data memory:
PCL and PCLATH
Stack
Indirect Addressing

3.1

Program Memory Organization

The enhanced mid-range core has a 15-bit program

counter capable of addressing 32K x 14 program
memory space. Table 3-1 shows the memory sizes
implemented. Accessing a location above these
boundaries will cause a wrap-around within the
implemented memory space. The Reset vector is at
0000h and the interrupt vector is at 0004h (See
Figure 3-1).

DEVICE SIZES AND ADDRESSES

Program Memory
Space (Words)

Last Program Memory

Address

High-Endurance Flash
Memory Address Range (1)

PIC16F1508
PIC16LF1508

4,096

0FFFh

0F80h-0FFFh

PIC16F1509
PIC16LF1509

8,192

1FFFh

1F80h-1FFFh

Device

Note 1: High-endurance Flash applies to low byte of each address in the range.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 17

PIC16(L)F1508/9
FIGURE 3-1:

PROGRAM MEMORY MAP

AND STACK FOR
PIC16(L)F1508

FIGURE 3-2:

PC<14:0>
CALL, CALLW
RETURN, RETLW
Interrupt, RETFIE

On-chip
Program
Memory

PROGRAM MEMORY MAP

AND STACK FOR
PIC16(L)F1509
PC<14:0>

CALL, CALLW
RETURN, RETLW
Interrupt, RETFIE

Stack Level 0
Stack Level 1

Stack Level 15

Reset Vector

0000h

Reset Vector

0000h

Interrupt Vector

0004h
0005h

Interrupt Vector

0004h
0005h

Page 0

07FFh
0800h

Page 1
Rollover to Page 0

0FFFh
1000h

On-chip
Program
Memory

Page 1
0FFFh
1000h
Page 2

Page 3
Rollover to Page 0

Rollover to Page 1

DS41609A-page 18

Rollover to Page 3

7FFFh

Preliminary

17FFh
1800h
1FFFh
2000h

7FFFh

2011 Microchip Technology Inc.

PIC16(L)F1508/9
3.1.1

READING PROGRAM MEMORY AS

DATA

There are two methods of accessing constants in program memory. The first method is to use tables of
RETLW instructions. The second method is to set an
FSR to point to the program memory.

3.1.1.1

RETLW Instruction

The RETLW instruction can be used to provide access

to tables of constants. The recommended way to create
such a table is shown in Example 3-1.

EXAMPLE 3-1:
constants
BRW

RETLW
RETLW
RETLW
RETLW

DATA0
DATA1
DATA2
DATA3

RETLW INSTRUCTION

3.1.1.2

Indirect Read with FSR

The program memory can be accessed as data by setting bit 7 of the FSRxH register and reading the matching INDFx register. The MOVIW instruction will place the
lower 8 bits of the addressed word in the W register.
Writes to the program memory cannot be performed via
the INDF registers. Instructions that access the program memory via the FSR require one extra instruction
cycle to complete. Example 3-2 demonstrates accessing the program memory via an FSR.
The HIGH directive will set bit<7> if a label points to a
location in program memory.

EXAMPLE 3-2:

;Add Index in W to
;program counter to
;select data
;Index0 data
;Index1 data

my_function
; LOTS OF CODE
MOVLW
DATA_INDEX
call constants
; THE CONSTANT IS IN W

ACCESSING PROGRAM
MEMORY VIA FSR

constants
RETLW DATA0
;Index0 data
RETLW DATA1
;Index1 data
RETLW DATA2
RETLW DATA3
my_function
; LOTS OF CODE
MOVLW
LOW constants
MOVWF
FSR1L
MOVLW
HIGH constants
MOVWF
FSR1H
MOVIW
0[FSR1]
;THE PROGRAM MEMORY IS IN W

The BRW instruction makes this type of table very simple to implement. If your code must remain portable
with previous generations of microcontrollers, then the
BRW instruction is not available so the older table read
method must be used.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 19

PIC16(L)F1508/9
3.2

Data Memory Organization

3.2.1

The data memory is partitioned in 32 memory banks

with 128 bytes in a bank. Each bank consists of
(Figure 3-3):

12 core registers
20 Special Function Registers (SFR)
Up to 80 bytes of General Purpose RAM (GPR)
16 bytes of common RAM

The core registers contain the registers that directly

affect the basic operation. The core registers occupy
the first 12 addresses of every data memory bank
(addresses x00h/x08h through x0Bh/x8Bh). These
registers are listed below in Table 3-2. For detailed
information, see Table 3-8.

TABLE 3-2:

The active bank is selected by writing the bank number

into the Bank Select Register (BSR). Unimplemented
memory will read as 0. All data memory can be
accessed either directly (via instructions that use the
file registers) or indirectly via the two File Select
Registers (FSR). See Section 3.5 Indirect
Addressing for more information.
Data memory uses a 12-bit address. The upper 7-bits
of the address define the Bank address and the lower
5-bits select the registers/RAM in that bank.

DS41609A-page 20

CORE REGISTERS

Preliminary

CORE REGISTERS
Addresses

BANKx

x00h or x80h
x01h or x81h
x02h or x82h
x03h or x83h
x04h or x84h
x05h or x85h
x06h or x86h
x07h or x87h
x08h or x88h
x09h or x89h
x0Ah or x8Ah
x0Bh or x8Bh

INDF0
INDF1
PCL
STATUS
FSR0L
FSR0H
FSR1L
FSR1H
BSR
WREG
PCLATH
INTCON

2011 Microchip Technology Inc.

PIC16(L)F1508/9
3.2.1.1

STATUS Register

The STATUS register, shown in Register 3-1, contains:

the arithmetic status of the ALU
the Reset status
The STATUS register can be the destination for any
instruction, like any other register. If the STATUS
register is the destination for an instruction that affects
the Z, DC or C bits, then the write to these three bits is
disabled. These bits are set or cleared according to the
device logic. Furthermore, the TO and PD bits are not
writable. Therefore, the result of an instruction with the
STATUS register as destination may be different than
intended.

It is recommended, therefore, that only BCF, BSF,

SWAPF and MOVWF instructions are used to alter the
STATUS register, because these instructions do not
affect any Status bits. For other instructions not
affecting any Status bits (Refer to Section 28.0
Instruction Set Summary).
Note 1: The C and DC bits operate as Borrow
and Digit Borrow out bits, respectively, in
subtraction.

STATUS: STATUS REGISTER

U-0

For example, CLRF STATUS will clear the upper three

bits and set the Z bit. This leaves the STATUS register
as 000u u1uu (where u = unchanged).

U-0

R-1/q

R/W-0/u

DC(1)

C(1)

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7-5

Unimplemented: Read as 0

bit 4

TO: Time-Out bit

1 = After power-up, CLRWDT instruction or SLEEP instruction
0 = A WDT time-out occurred

bit 3

PD: Power-Down bit

1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction

bit 2

Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero

bit 1

DC: Digit Carry/Digit Borrow bit (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1)
1 = A carry-out from the 4th low-order bit of the result occurred
0 = No carry-out from the 4th low-order bit of the result

bit 0

C: Carry/Borrow bit(1) (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1)

1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred

Note 1:

For Borrow, the polarity is reversed. A subtraction is executed by adding the twos complement of the
second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order
bit of the source register.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 21

PIC16(L)F1508/9
3.2.2

SPECIAL FUNCTION REGISTER

FIGURE 3-3:

The Special Function Registers are registers used by

the application to control the desired operation of
peripheral functions in the device. The Special Function
Registers occupy the 20 bytes after the core registers of
every data memory bank (addresses x0Ch/x8Ch
through x1Fh/x9Fh). The registers associated with the
operation of the peripherals are described in the appropriate peripheral chapter of this data sheet.

3.2.3

7-bit Bank Offset

0Bh
0Ch

GENERAL PURPOSE RAM

Core Registers
(12 bytes)

Special Function Registers

(20 bytes maximum)
1Fh
20h

Linear Access to GPR

The general purpose RAM can be accessed in a

non-banked method via the FSRs. This can simplify
access to large memory structures. See Section 3.5.2
Linear Data Memory for more information.

3.2.4

Memory Region

00h

There are up to 80 bytes of GPR in each data memory

bank. The Special Function Registers occupy the 20
bytes after the core registers of every data memory
bank (addresses x0Ch/x8Ch through x1Fh/x9Fh).

3.2.3.1

BANKED MEMORY
PARTITIONING

General Purpose RAM

(80 bytes maximum)

COMMON RAM

There are 16 bytes of common RAM accessible from all

banks.

6Fh
70h
Common RAM
(16 bytes)
7Fh

3.2.5

DEVICE MEMORY MAPS

The memory maps for PIC16(L)F1508/9 are as shown

in Table 3-5 and Table 3-6.

DS41609A-page 22

Preliminary

2011 Microchip Technology Inc.

TABLE 3-3:

PIC16(L)F1508 MEMORY MAP, BANK 1-7

BANK 0
000h

BANK 1
080h

Core Registers
(Table 3-2)

Preliminary

00Bh
00Ch
00Dh
00Eh
00Fh
010h
011h
012h
013h
014h
015h
016h
017h
018h
019h
01Ah
01Bh
01Ch
01Dh
01Eh
01Fh
020h

PORTA
PORTB
PORTC

PIR1
PIR2
PIR3

TMR0
TMR1L
TMR1H
T1CON
T1GCON
TMR2
PR2
T2CON

Core Registers
(Table 3-2)
08Bh
08Ch
08Dh
08Eh
08Fh
090h
091h
092h
093h
094h
095h
096h
097h
098h
099h
09Ah
09Bh
09Ch
09Dh
09Eh
09Fh
0A0h

Legend:

ADCON0
ADCON1
ADCON2

Core Registers
(Table 3-2)
10Bh
10Ch
10Dh
10Eh
10Fh
110h
111h
112h
113h
114h
115h
116h
117h
118h
119h
11Ah
11Bh
11Ch
11Dh
11Eh
11Fh
120h

General
Purpose
Register
80 Bytes
0EFh
0F0h

Common RAM
07Fh

TRISA
TRISB
TRISC

PIE1
PIE2
PIE3

OPTION_REG
PCON
WDTCON

OSCCON
OSCSTAT
ADRESL
ADRESH

0FFh

Common RAM
(Accesses
70h 7Fh)

BANK 3
180h

LATA
LATB
LATC

CM1CON0
CM1CON1
CM2CON0
CM2CON1
CMOUT
BORCON
FVRCON
DACCON0
DACCON1

APFCON

Core Registers
(Table 3-2)
18Bh
18Ch
18Dh
18Eh
18Fh
190h
191h
192h
193h
194h
195h
196h
197h
198h
199h
19Ah
19Bh
19Ch
19Dh
19Eh
19Fh
1A0h

General
Purpose
Register
80 Bytes
16Fh
170h

17Fh

Common RAM
(Accesses
70h 7Fh)

= Unimplemented data memory locations, read as 0.

BANK 4
200h

ANSELA
ANSELB
ANSELC

PMADRL
PMADRH
PMDATL
PMDATH
PMCON1
PMCON2
VREGCON

RCREG
TXREG
SPBRG
SPBRGH
RCSTA
TXSTA
BAUDCON

Core Registers
(Table 3-2)
20Bh
20Ch
20Dh
20Eh
20Fh
210h
211h
212h
213h
214h
215h
216h
217h
218h
219h
21Ah
21Bh
21Ch
21Dh
21Eh
21Fh
220h

Unimplemented
Read as 0

1EFh
1F0h

1FFh

Common RAM
(Accesses
70h 7Fh)

BANK 5
280h

WPUA
WPUB

SSP1BUF
SSP1ADD
SSP1MSK
SSP1STAT
SSP1CON1
SSP1CON2
SSP1CON3

Core Registers
(Table 3-2)
28Bh
28Ch
28Dh
28Eh
28Fh
290h
291h
292h
293h
294h
295h
296h
297h
298h
299h
29Ah
29Bh
29Ch
29Dh
29Eh
29Fh
2A0h

Unimplemented
Read as 0

26Fh
270h

27Fh

Common RAM
(Accesses
70h 7Fh)

BANK 6
300h

Core Registers
(Table 3-2)
30Bh
30Ch
30Dh
30Eh
30Fh
310h
311h
312h
313h
314h
315h
316h
317h
318h
319h
31Ah
31Bh
31Ch
31Dh
31Eh
31Fh
320h

Unimplemented
Read as 0

2EFh
2F0h

2FFh

Common RAM
(Accesses
70h 7Fh)

BANK 7
380h

Core Registers
(Table 3-2)
38Bh
38Ch
38Dh
38Eh
38Fh
390h
391h
392h
393h
394h
395h
396h
397h
398h
399h
39Ah
39Bh
39Ch
39Dh
39Eh
39Fh
3A0h

Unimplemented
Read as 0

36Fh
370h

37Fh

Common RAM
(Accesses
70h 7Fh)

IOCAP
IOCAN
IOCAF
IOCBP
IOCBN
IOCBF

Unimplemented
Read as 0

3EFh
3F0h

3FFh

Common RAM
(Accesses
70h 7Fh)

DS41609A-page 23

PIC16(L)F1508/9

General
Purpose
Register
80 Bytes
06Fh
070h

BANK 2
100h

PIC16(L)F1509 MEMORY MAP, BANK 1-7

BANK 0
000h

BANK 1
080h

Core Registers
(Table 3-2)

Preliminary

00Bh
00Ch
00Dh
00Eh
00Fh
010h
011h
012h
013h
014h
015h
016h
017h
018h
019h
01Ah
01Bh
01Ch
01Dh
01Eh
01Fh

BANK 2
100h

Core Registers
(Table 3-2)

BANK 3
180h

Core Registers
(Table 3-2)

PORTA
PORTB
PORTC

PIR1
PIR2
PIR3

TMR0
TMR1L
TMR1H
T1CON
T1GCON
TMR2
PR2
T2CON

08Bh
08Ch
08Dh
08Eh
08Fh
090h
091h
092h
093h
094h
095h
096h
097h
098h
099h
09Ah
09Bh
09Ch

TRISA
TRISB
TRISC

PIE1
PIE2
PIE3

OPTION_REG
PCON
WDTCON

OSCCON
OSCSTAT
ADRESL
ADRESH

10Bh
10Ch
10Dh
10Eh
10Fh
110h
111h
112h
113h
114h
115h
116h
117h
118h
119h
11Ah
11Bh
11Ch

09Dh
09Eh
09Fh

ADCON0
ADCON1
ADCON2

11Dh
11Eh
11Fh

LATA
LATB
LATC

CM1CON0
CM1CON1
CM2CON0
CM2CON1
CMOUT
BORCON
FVRCON
DACCON0
DACCON1

APFCON

BANK 4
200h

Core Registers
(Table 3-2)
18Bh
18Ch
18Dh
18Eh
18Fh
190h
191h
192h
193h
194h
195h
196h
197h
198h
199h
19Ah
19Bh
19Ch
19Dh
19Eh
19Fh

ANSELA
ANSELB
ANSELC

PMADRL
PMADRH
PMDATL
PMDATH
PMCON1
PMCON2
VREGCON

RCREG
TXREG
SPBRG
SPBRGH
RCSTA
TXSTA
BAUDCON

BANK 5
280h

Core Registers
(Table 3-2)
20Bh
20Ch
20Dh
20Eh
20Fh
210h
211h
212h
213h
214h
215h
216h
217h
218h
219h
21Ah
21Bh
21Ch
21Dh
21Eh
21Fh

WPUA
WPUB

SSP1BUF
SSP1ADD
SSP1MSK
SSP1STAT
SSP1CON1
SSP1CON2
SSP1CON3

Core Registers
(Table 3-2)
28Bh
28Ch
28Dh
28Eh
28Fh
290h
291h
292h
293h
294h
295h
296h
297h
298h
299h
29Ah
29Bh
29Ch
29Dh
29Eh
29Fh

0A0h
020h

General
Purpose
Register
80 Bytes

General
Purpose
Register
80 Bytes
0EFh
0F0h

06Fh
070h

2011 Microchip Technology Inc.

Common RAM
07Fh
Legend:

0FFh

Common RAM
(Accesses
70h 7Fh)

120h

16Fh
170h

17Fh

General
Purpose
Register
80 Bytes

Common RAM
(Accesses
70h 7Fh)

= Unimplemented data memory locations, read as 0.

1A0h

1EFh
1F0h

1FFh

General
Purpose
Register
80 Bytes

Common RAM
(Accesses
70h 7Fh)

220h

26Fh
270h

27Fh

General
Purpose
Register
80 Bytes

Common RAM
(Accesses
70h 7Fh)

BANK 6
300h

2A0h

2EFh
2F0h

2FFh

Core Registers
(Table 3-2)
30Bh
30Ch
30Dh
30Eh
30Fh
310h
311h
312h
313h
314h
315h
316h
317h
318h
319h
31Ah
31Bh
31Ch
31Dh
31Eh
31Fh
320h

General
Purpose
Register
80 Bytes

Common RAM
(Accesses
70h 7Fh)

BANK 7
380h

General Purpose
Register
16Bytes

Core Registers
(Table 3-2)
38Bh
38Ch
38Dh
38Eh
38Fh
390h
391h
392h
393h
394h
395h
396h
397h
398h
399h
39Ah
39Bh
39Ch
39Dh
39Eh
39Fh

37Fh

Common RAM
(Accesses
70h 7Fh)

IOCBP
IOCBN
IOCBF

3A0h
Unimplemented
Read as 0

Unimplemented
Read as 0
36Fh
370h

IOCAP
IOCAN
IOCAF

3EFh
3F0h

3FFh

Common RAM
(Accesses
70h 7Fh)

PIC16(L)F1508/9

DS41609A-page 24

TABLE 3-4:

2011 Microchip Technology Inc.

TABLE 3-5:

PIC16(L)F1508/9 MEMORY MAP, BANK 8-23

BANK 8
400h

BANK 9
480h
Core Registers
(Table 3-2)

Core Registers
(Table 3-2)

Preliminary

40Bh
40Ch
40Dh
40Eh
40Fh
410h
411h
412h
413h
414h
415h
416h
417h
418h
419h
41Ah
41Bh
41Ch
41Dh
41Eh
41Fh
420h

48Bh
48Ch
48Dh
48Eh
48Fh
490h
491h
492h
493h
494h
495h
496h
497h
498h
499h
49Ah
49Bh
49Ch
49Dh
49Eh
49Fh
4A0h

Unimplemented
Read as 0

46Fh
470h

47Fh

4EFh
4F0h

4FFh

Common RAM
(Accesses
70h 7Fh)

Core Registers
(Table 3-2 )

DS41609A-page 25

87Fh
Legend:

Common RAM
(Accesses
70h 7Fh)

56Fh
570h

57Fh

8FFh

5EFh
5F0h

5FFh

= Unimplemented data memory locations, read as 0.

64Fh
650h

67Fh

6EFh
6F0h

6FFh

76Fh
770h

77Fh

78Bh
78Ch
78Dh
78Eh
78Fh
790h
791h
792h
793h
794h
795h
796h
797h
798h
799h
79Ah
79Bh
79Ch
79Dh
79Eh
79Fh
7A0h

7EFh
7F0h

7FFh

BANK 23
Core Registers
(Table 3-2)
B8Bh
B8Ch

Unimplemented
Read as 0

B7Fh

Common RAM
(Accesses
70h 7Fh)

B80h
Core Registers
(Table 3-2)

B6Fh
B70h

Unimplemented
Read as 0

BANK 22

Unimplemented
Read as 0

AFFh

Common RAM
(Accesses
70h 7Fh)

B0Bh
B0Ch

Common RAM
(Accesses
70h 7Fh)

Core Registers
(Table 3-2)

Unimplemented
Read as 0

Core Registers
(Table 3-2)

AEFh
AF0h

B00h

A8Bh
A8Ch

Common RAM
(Accesses
70h 7Fh)

70Bh
70Ch
70Dh
70Eh
70Fh
710h
711h
712h
713h
714h
715h
716h
717h
718h
719h
71Ah
71Bh
71Ch
71Dh
71Eh
71Fh
720h

BANK 21

Unimplemented
Read as 0

A7Fh

Common RAM
(Accesses
70h 7Fh)

BANK 15
780h

Core Registers
(Table 3-2)

Unimplemented
Read as 0

Core Registers
(Table 3-2)

A6Fh
A70h

CWG1DBR
CWG1DBF
CWG1CON0
CWG1CON1
CWG1CON2

A80h

A0Bh
A0Ch

Common RAM
(Accesses
70h 7Fh)

68Bh
68Ch
68Dh
68Eh
68Fh
690h
691h
692h
693h
694h
695h
696h
697h
698h
699h
69Ah
69Bh
69Ch
69Dh
69Eh
69Fh
6A0h

BANK 20

Unimplemented
Read as 0

9FFh

Common RAM
(Accesses
70h 7Fh)

BANK 14
700h

Core Registers
(Table 3-2)

Unimplemented
Read as 0

Core Registers
(Table 3-2)

9EFh
9F0h

PWM1DCL
PWM1DCH
PWM1CON
PWM2DCL
PWM2DCH
PWM2CON
PWM3DCL
PWM3DCH
PWM3CON
PWM4DCL
PWM4DCH
PWM4CON

A00h

98Bh
98Ch

Common RAM
(Accesses
70h 7Fh)

60Bh
60Ch
60Dh
60Eh
60Fh
610h
611h
612h
613h
614h
615h
616h
617h
618h
619h
61Ah
61Bh
61Ch
61Dh
61Eh
61Fh
620h

BANK 19

Unimplemented
Read as 0

97Fh

Common RAM
(Accesses
70h 7Fh)

BANK 13
680h

Core Registers
(Table 3-2)

Unimplemented
Read as 0

Core Registers
(Table 3-2)

96Fh
970h

980h

90Bh
90Ch

Common RAM
(Accesses
70h 7Fh)

58Bh
58Ch
58Dh
58Eh
58Fh
590h
591h
592h
593h
594h
595h
596h
597h
598h
599h
59Ah
59Bh
59Ch
59Dh
59Eh
59Fh
5A0h

BANK 18

Unimplemented
Read as 0
8EFh
8F0h

Common RAM
(Accesses
70h 7Fh)

BANK 12
600h

Core Registers
(Table 3-2)

Unimplemented
Read as 0

Core Registers
(Table 3-2)

Unimplemented
Read as 0

900h

88Bh
88Ch

86Fh
870h

50Bh
50Ch
50Dh
50Eh
50Fh
510h
511h
512h
513h
514h
515h
516h
517h
518h
519h
51Ah
51Bh
51Ch
51Dh
51Eh
51Fh
520h

BANK 17
880h

80Bh
80Ch

Core Registers
(Table 3-2)

Unimplemented
Read as 0

BANK 16
800h

NCO1ACCL
NCO1ACCH
NCO1ACCU
NCO1INCL
NCO1INCH

NCO1CON
NCO1CLK

BANK 11
580h

Common RAM
(Accesses
70h 7Fh)

Unimplemented
Read as 0
BEFh
BF0h

BFFh

Common RAM
(Accesses
70h 7Fh)

PIC16(L)F1508/9

Common RAM
(Accesses
70h 7Fh)

BANK 10
500h

PIC16(L)F1508/9 MEMORY MAP, BANK 24-31

BANK 24
C00h

BANK 25
C80h

Core Registers
(Table 3-2)

Preliminary

C0Bh
C0Ch
C0Dh
C0Eh
C0Fh
C10h
C11h
C12h
C13h
C14h
C15h
C16h
C17h
C18h
C19h
C1Ah
C1Bh
C1Ch
C1Dh
C1Eh
C1Fh
C20h

Core Registers
(Table 3-2)
C8Bh
C8Ch
C8Dh
C8Eh
C8Fh
C90h
C91h
C92h
C93h
C94h
C95h
C96h
C97h
C98h
C99h
C9Ah
C9Bh
C9Ch
C9Dh
C9Eh
C9Fh
CA0h

Unimplemented
Read as 0
C6Fh
C70h

2011 Microchip Technology Inc.

CFFh
Legend:

Common RAM
(Accesses
70h 7Fh)

BANK 26
D00h

Core Registers
(Table 3-2)
D0Bh
D0Ch
D0Dh
D0Eh
D0Fh
D10h
D11h
D12h
D13h
D14h
D15h
D16h
D17h
D18h
D19h
D1Ah
D1Bh
D1Ch
D1Dh
D1Eh
D1Fh
D20h

Unimplemented
Read as 0
CEFh
CF0h

CFFh

Common RAM
(Accesses
70h 7Fh)

BANK 27
D80h

Core Registers
(Table 3-2)
D8Bh
D8Ch
D8Dh
D8Eh
D8Fh
D90h
D91h
D92h
D93h
D94h
D95h
D96h
D97h
D98h
D99h
D9Ah
D9Bh
D9Ch
D9Dh
D9Eh
D9Fh
DA0h

Unimplemented
Read as 0
D6Fh
D70h

D7Fh

Common RAM
(Accesses
70h 7Fh)

= Unimplemented data memory locations, read as 0.

BANK 28
E00h

Core Registers
(Table 3-2)
E0Bh
E0Ch
E0Dh
E0Eh
E0Fh
E10h
E11h
E12h
E13h
E14h
E15h
E16h
E17h
E18h
E19h
E1Ah
E1Bh
E1Ch
E1Dh
E1Eh
E1Fh
E20h

Unimplemented
Read as 0
DEFh
DF0h

DFFh

Common RAM
(Accesses
70h 7Fh)

BANK 29
E80h

Core Registers
(Table 3-2)
E8Bh
E8Ch
E8Dh
E8Eh
E8Fh
E90h
E91h
E92h
E93h
E94h
E95h
E96h
E97h
E98h
E99h
E9Ah
E9Bh
E9Ch
E9Dh
E9Eh
E9Fh
EA0h

Unimplemented
Read as 0
E6Fh
E70h

E7Fh

Common RAM
(Accesses
70h 7Fh)

BANK 30
F00h

BANK 31
F80h

Core Registers
(Table 3-2)

F0Bh
F0Ch
F0Dh
F0Eh
F0Fh
F10h
F11h
F12h
F13h
F14h
F15h
F16h
F17h
See Table 3-7 for
F18h register mapping
F19h
details
F1Ah
F1Bh
F1Ch
F1Dh
F1Eh
F1Fh
F20h

F8Bh
F8Ch
F8Dh
F8Eh
F8Fh
F90h
F91h
F92h
F93h
F94h
F95h
F96h
F97h
See Table 3-7 for
F98h register mapping
F99h
details
F9Ah
F9Bh
F9Ch
F9Dh
F9Eh
F9Fh
FA0h

F6Fh
F70h

FEFh
FF0h

Unimplemented
Read as 0
EEFh
EF0h

EFFh

Common RAM
(Accesses
70h 7Fh)

F7Fh

Common RAM
(Accesses
70h 7Fh)

FFFh

Common RAM
(Accesses
70h 7Fh)

PIC16(L)F1508/9

DS41609A-page 26

TABLE 3-6:

PIC16(L)F1508/9
TABLE 3-7:

PIC16(L)F1508/9 MEMORY MAP, BANK 30-31

Bank 31

Bank 30
F0Ch
F0Dh
F0Eh
F0Fh
F10h
F11h
F12h
F13h
F14h
F15h
F16h
F17h
F18h
F19h
F1Ah
F1Bh
F1Ch
F1Dh
F1Eh
F1Fh
F20h
F21h
F22h
F23h
F24h
F25h
F26h
F27h
F2Ah
F2Bh
F2Ch
F2Dh
F2Eh
F2Fh
F31h
F31h
F32h
F6Fh

Legend:

F8Ch

CLCDATA
CLC1CON
CLC1POL
CLC1SEL0
CLC1SEL1
CLC1GLS0
CLC1GLS1
CLC1GLS2
CLC1GLS3
CLC2CON
CLC2POL
CLC2SEL0
CLC2SEL1
CLC2GLS0
CLC2GLS1
CLC2GLS2
CLC2GLS3
CLC3CON
CLC3POL
CLC3SEL0
CLC3SEL1
CLC3GLS0
CLC3GLS1
CLC3GLS2
CLC3GLS3
CLC4CON
CLC4POL
CLC4SEL0
CLC4SEL1
CLC4GLS0
CLC4GLS1
CLC4GLS2
CLC4GLS3

Unimplemented
Read as 0
FE3h
FE4h
FE5h
FE6h
FE7h
FE8h
FE9h
FEAh
FEBh
FECh
FEDh
FEEh
FEFh

STATUS_SHAD
WREG_SHAD
BSR_SHAD
PCLATH_SHAD
FSR0L_SHAD
FSR0H_SHAD
FSR1L_SHAD
FSR1H_SHAD

STKPTR
TOSL
TOSH

Unimplemented
Read as 0

= Unimplemented data memory locations, read as 0.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 27

PIC16(L)F1508/9
3.2.6

CORE FUNCTION REGISTERS

SUMMARY

The Core Function registers listed in Table 3-8 can be

addressed from any Bank.

TABLE 3-8:
Addr

Name

CORE FUNCTION REGISTERS SUMMARY

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Value on
POR, BOR

Value on all
other Resets

Bank 0-31
x00h or
INDF0
x80h

Addressing this location uses contents of FSR0H/FSR0L to address data memory

(not a physical register)

xxxx xxxx

uuuu uuuu

x01h or
INDF1
x81h

Addressing this location uses contents of FSR1H/FSR1L to address data memory

(not a physical register)

xxxx xxxx

uuuu uuuu

x02h or
PCL
x82h

Program Counter (PC) Least Significant Byte

0000 0000

---1 1000

---q quuu

x03h or
STATUS
x83h

x04h or
FSR0L
x84h

Indirect Data Memory Address 0 Low Pointer

0000 0000

uuuu uuuu

x05h or
FSR0H
x85h

Indirect Data Memory Address 0 High Pointer

0000 0000

x06h or
FSR1L
x86h

Indirect Data Memory Address 1 Low Pointer

0000 0000

uuuu uuuu

x07h or
FSR1H
x87h

Indirect Data Memory Address 1 High Pointer

0000 0000

---0 0000

0000 0000

uuuu uuuu

-000 0000

0000 0000

x08h or
BSR
x88h

x09h or
WREG
x89h

BSR<4:0>

Working Register

x0Ah or
PCLATH
x8Ah

x0Bh or
INTCON
x8Bh

GIE

Legend:

Write Buffer for the upper 7 bits of the Program Counter

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as 0, r = reserved.

Shaded locations are unimplemented, read as 0.

DS41609A-page 28

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 3-9:
Address

SPECIAL FUNCTION REGISTER SUMMARY

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Value on
POR, BOR

Value on all
other
Resets

Bank 0
00Ch

PORTA

RA5

RA4

RA3

RA2

RA1

RA0

--xx xxxx --xx xxxx

00Dh

PORTB

RB7

RB6

RB5

RB4

xxxx ---- xxxx ----

00Eh

PORTC

RC7

RC6

RC5

RC4

RC3

RC2

RC1

RC0

xxxx xxxx xxxx xxxx

00Fh

Unimplemented

010h

Unimplemented

011h

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

0000 0-00 0000 0-00

012h

PIR2

OSFIF

C2IF

C1IF

BCL1IF

NCO1IF

000- -0-- 000- -0--

013h

PIR3

CLC4IF

CLC3IF

CLC2IF

CLC1IF

---- 0000 ---- 0000

014h

Unimplemented

015h

TMR0

Holding Register for the 8-bit Timer0 Count

xxxx xxxx uuuu uuuu

016h

TMR1L

Holding Register for the Least Significant Byte of the 16-bit TMR1 Count

xxxx xxxx uuuu uuuu

017h

TMR1H

Holding Register for the Most Significant Byte of the 16-bit TMR1 Count

018h

T1CON

019h

T1GCON

01Ah

TMR2

Timer2 Module Register

01Bh

PR2

Timer2 Period Register

01Ch

T2CON

01Dh

Unimplemented

01Eh

Unimplemented

01Fh

Unimplemented

TMR1CS<1:0>
TMR1GE

T1GPOL

T1CKPS<1:0>
T1GTM

T1GSPM

T1OSCEN

T1SYNC

T1GGO/
DONE

T1GVAL

xxxx xxxx uuuu uuuu

TMR1ON
T1GSS<1:0>

0000 00-0 uuuu uu-u

0000 0x00 uuuu uxuu
0000 0000 0000 0000
1111 1111 1111 1111

T2OUTPS<3:0>

TMR2ON

T2CKPS<1:0>

-000 0000 -000 0000

Bank 1
08Ch

TRISA

TRISA5

TRISA4

(2)

TRISA2

TRISA1

TRISA0

--11 1111 --11 1111

08Dh

TRISB

TRISB7

TRISB6

TRISB5

TRISB4

1111 ---- 1111 ----

08Eh

TRISC

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

1111 1111 1111 1111

08Fh

Unimplemented

090h

Unimplemented

091h

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

0000 0-00 0000 0-00

092h

PIE2

OSFIE

C2IE

C1IE

BCL1IE

NCO1IE

000- 00-- 000- 00--

093h

PIE3

CLC4IE

CLC3IE

CLC2IE

CLC1IE

---- 0000 ---- 0000

094h

095h

OPTION_REG

WPUEN

INTEDG

TMR0CS

TMR0SE

PSA

STKOVF

STKUNF

RWDT

Unimplemented

096h

PCON

097h

WDTCON

098h

099h

OSCCON

09Ah

OSCSTAT

SOSCR

09Bh

ADRESL

09Ch

ADRESH

09Dh

ADCON0

09Eh

ADCON1

ADFM

09Fh

ADCON2

RMCLR

PS<2:0>
RI

POR

WDTPS<4:0>

BOR

00-1 11qq qq-q qquu

SWDTEN

--01 0110 --01 0110

Unimplemented

IRCF<3:0>

OSTS

HFIOFR

SCS<1:0>
LFIOFR

1111 1111 1111 1111

-011 1-00 -011 1-00

HFIOFS

0-q0 --00 q-qq --qq

xxxx xxxx uuuu uuuu

A/D Result Register High

xxxx xxxx uuuu uuuu

CHS<4:0>
ADCS<2:0>

TRIGSEL<3:0>

GO/DONE

ADON

ADPREF<1:0>

-000 0000 -000 0000

0000 --00 0000 --00
0000 ---- 0000 ----

Legend:
x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as 0.
Note 1:
PIC16F1508/9 only.
2:
Unimplemented, read as 1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 29

PIC16(L)F1508/9
TABLE 3-9:
Address

SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Value on
POR, BOR

Value on all
other
Resets

Bank 2
10Ch

LATA

LATA5

LATA4

LATA2

LATA1

LATA0

--xx -xxx --uu -uuu

10Dh

LATB

LATB7

LATB6

LATB5

LATB4

xxxx ---- uuuu ----

10Eh

LATC

LATC7

LATC6

LATC5

LATC4

LATC3

LATC2

LATC1

LATC0

xxxx xxxx uuuu uuuu

10Fh

Unimplemented

110h

Unimplemented

111h

CM1CON0

C1ON

C1OUT

112h

CM1CON1

C1INTP

C1INTN

113h

CM2CON0

C2ON

C2OUT

114h

CM2CON1

C2INTP

C2INTN

115h

CMOUT

116h

BORCON

SBOREN

BORFS

117h

FVRCON

FVREN

FVRRDY

TSEN

TSRNG

118h

DACCON0

DACEN

DACOE1

DACOE2

119h

DACCON1

11Ah
to
11Ch

C1OE

C1POL

C1PCH<1:0>
C2OE

C1SP

C2POL

C2PCH<1:0>

C1HYS
C1NCH<2:0>

C2SP

C2HYS
MC2OUT

0000 -000 0000 -000

---- --00 ---- --00

BORRDY

10-- ---q uu-- ---u

DACR<4:0>

0q00 0000 0q00 0000

0-00 -0-- 0-00 -0----0 0000 ---0 0000

Unimplemented

0000 -100 0000 -100

MC1OUT

ADFVR<1:0>

DACPSS

0000 -100 0000 -100

0000 -000 0000 -000

C2SYNC

C2NCH<2:0>

CDAFVR<1:0>

C1SYNC

SSSEL

T1GSEL

CLC1SEL

NCO1SEL

11Dh

APFCON

11Eh

Unimplemented

11Fh

Unimplemented

---0 0-00 ---0 0-00

Bank 3
18Ch

ANSELA

ANSA4

ANSA2

ANSA1

ANSA0

---1 -111 ---1 -111

18Dh

ANSELB

ANSB5

ANSB4

--11 ---- --11 ----

18Eh

ANSELC

ANSC7

ANSC6

ANSC3

ANSC2

ANSC1

ANSC0

11-- 1111 11-- 1111

18Fh

Unimplemented

190h

Unimplemented

191h

PMADRL

Flash Program Memory Address Register Low Byte

192h

PMADRH

193h

PMDATL

194h

PMDATH

195h

PMCON1

(2)

CFGS

196h

PMCON2

197h

VREGCON(1)

0000 0000 0000 0000

Flash Program Memory Address Register High Byte

-000 0000 -000 0000

Flash Program Memory Read Data Register Low Byte

xxxx xxxx uuuu uuuu

Flash Program Memory Read Data Register High Byte

LWLO

FREE

--xx xxxx --uu uuuu

WRERR

WREN

0000 x000 0000 q000

VREGPM

Reserved

---- --01 ---- --01

Flash Program Memory Control Register 2

0000 0000 0000 0000

198h

Unimplemented

199h

RCREG

USART Receive Data Register

0000 0000 0000 0000

19Ah

TXREG

USART Transmit Data Register

0000 0000 0000 0000

19Bh

SPBRGL

Baud Rate Generator Data Register Low

0000 0000 0000 0000

19Ch

SPBRGH

Baud Rate Generator Data Register High

19Dh

RCSTA

SPEN

RX9

SREN

CREN

ADDEN

FERR

OERR

RX9D

0000 000x 0000 000x

19Eh

TXSTA

CSRC

TX9

TXEN

SYNC

SENDB

BRGH

TRMT

TX9D

0000 0010 0000 0010

19Fh

BAUDCON

ABDOVF

RCIDL

SCKP

BRG16

WUE

ABDEN

01-0 0-00 01-0 0-00

0000 0000 0000 0000

DS41609A-page 30

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 3-9:
Address

SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Value on
POR, BOR

Value on all
other
Resets

Bank 4
20Ch

WPUA

WPUA5

WPUA4

WPUA3

WPUA2

WPUA1

WPUA0

--11 1111 --11 1111

20Dh

WPUB

WPUB7

WPUB6

WPUB5

WPUB4

1111 ---- 1111 ----

20Eh
to
210h

Unimplemented

211h

SSP1BUF

Synchronous Serial Port Receive Buffer/Transmit Register

xxxx xxxx uuuu uuuu

212h

SSP1ADD

ADD<7:0>

0000 0000 0000 0000

213h

SSP1MSK

MSK<7:0>

214h

SSP1STAT

SMP

CKE

D/A

215h

SSP1CON1

WCOL

SSPOV

SSPEN

CKP

216h

SSP1CON2

GCEN

ACKSTAT

ACKDT

ACKEN

RCEN

PEN

RSEN

SEN

0000 0000 0000 0000

217h

SSP1CON3

ACKTIM

PCIE

SCIE

BOEN

SDAHT

SBCDE

AHEN

DHEN

0000 0000 0000 0000

218h
to
21Fh

1111 1111 1111 1111

R/W

0000 0000 0000 0000

SSPM<3:0>

0000 0000 0000 0000

Unimplemented

Bank 5
28Ch
to
29Fh

Bank 6
30Ch
to
31Fh

Bank 7
38Ch
to
390h
391h

IOCAP

IOCAP5

IOCAP4

IOCAP3

IOCAP2

IOCAP1

IOCAP0

--00 0000 --00 0000

392h

IOCAN

IOCAN5

IOCAN4

IOCAN3

IOCAN2

IOCAN1

IOCAN0

--00 0000 --00 0000

393h

IOCAF

IOCAF5

IOCAF4

IOCAF3

IOCAF2

IOCAF1

IOCAF0

--00 0000 --00 0000

394h

IOCBP

IOCBP7

IOCBP6

IOCBP5

IOCBP4

0000 ---- 0000 ----

395h

IOCBN

IOCBN7

IOCBN6

IOCBN5

IOCBN4

0000 ---- 0000 ----

396h

IOCBF

IOCBF7

IOCBF6

IOCBF5

IOCBF4

0000 ---- 0000 ----

397h
to
39Fh

Unimplemented

Bank 8
40Ch
to
41Fh

Bank 9
48Ch
to
497h
498h

NCO1ACCL

NCO1ACC<7:0>

0000 0000 0000 0000

499h

NCO1ACCH

NCO1ACC<15:8>

0000 0000 0000 0000

49Ah

NCO1ACCU

NCO1ACC<19:16>

0000 0000 0000 0000

49Bh

NCO1INCL

NCO1INC<7:0>

0000 0000 0000 0000

49Ch

NCO1INCH

NCO1INC<15:8>

0000 0000 0000 0000

49Dh

49Eh

NCO1CON

49Fh

NCO1CLK

Unimplemented
N1EN

N1OE
N1PWS<2:0>

N1OUT

N1POL

N1PFM
N1CKS<1:0>

0000 ---0 0000 ---0

0000 --00 0000 --00

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 31

PIC16(L)F1508/9
TABLE 3-9:
Address

SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)

Name

Value on
POR, BOR

Value on all
other
Resets

Unimplemented

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Bank 10
50Ch
to
51Fh

Bank 11
58Ch
to
59Fh

Bank 12
60Ch
to
610h

611h

PWM1DCL

612h

PWM1DCH

613h

PWM1CON0

614h

PWM2DCL

615h

PWM2DCH

616h

PWM2CON0

617h

PWM3DCL

618h

PWM3DCH

619h

PWM3CON0

61Ah

PWM4DCL

61Bh

PWM4DCH

61Ch

PWM4CON0

61Dh
to
61Fh

PWM1DCL<7:6>

PWM1DCH<7:0>
PWM1EN

xxxx xxxx uuuu uuuu

PWM1OE PWM1OUT PWM1POL

0000 ---- 0000 ----

00-- ---- 00-- ----

0000 ---- 0000 ----

00-- ---- 00-- ----

0000 ---- 0000 ----

00-- ---- 00-- ----

PWM2DCL<7:6>

PWM2DCH<7:0>
PWM2EN

PWM2OE PWM2OUT PWM2POL

PWM3DCL<7:6>

xxxx xxxx uuuu uuuu

PWM3DCH<7:0>
PWM3EN

PWM3OE PWM3OUT PWM3POL

PWM4DCL<7:6>

xxxx xxxx uuuu uuuu

PWM4DCH<7:0>
PWM4EN

00-- ---- 00-- ----

PWM4OE PWM4OUT PWM4POL

xxxx xxxx uuuu uuuu

0000 ---- 0000 ----

Unimplemented

Bank 13
68Ch
to
690h

691h

CWG1DBR

CWG1DBR<5:0>

692h

CWG1DBF

CWG1DBF<5:0>

693h

CWG1CON0

G1EN

G1OEB

694h

CWG1CON1

695h

CWG1CON2

696h
to
69Fh

G1ASDLB<1:0>
G1ASE

G1ARSEN

G1OEA

G1POLB

G1ASDLA<1:0>

G1POLA

G1ASDC2

Unimplemented

--00 0000 --00 0000

--xx xxxx --xx xxxx

G1CS0

G1IS<2:0>

0000 0--0 0000 0--0

0000 -000 0000 -000

G1ASDC1 G1ASDSFLT G1ASDSCLC2 00-- --00 00-- --00

DS41609A-page 32

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 3-9:
Address

Name

SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)

Value on
POR, BOR

Value on all
other
Resets

Unimplemented

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Banks 14-29
x0Ch/
x8Ch

x1Fh/
x9Fh

Bank 30
F0Ch
to
F0Eh

F0Fh

CLCDATA

F10h

CLC1CON

LC1EN

LC1OE

LC1OUT

LC1INTP

F11h

CLC1POL

LC1POL

F12h

CLC1SEL0

LC1D2S<2:0>

LC1D1S<2:0>

F13h

CLC1SEL1

LC1D4S<2:0>

LC1D3S<2:0>

F14h

CLC1GLS0

LC1G1D4T LC1G1D4N LC1G1D3T LC1G1D3N LC1G1D2T LC1G1D2N LC1G1D1T

LC1G1D1N

xxxx xxxx uuuu uuuu

F15h

CLC1GLS1

LC1G2D4T LC1G2D4N LC1G2D3T LC1G2D3N LC1G2D2T LC1G2D2N LC1G2D1T

LC1G2D1N

xxxx xxxx uuuu uuuu

F16h

CLC1GLS2

LC1G3D4T LC1G3D4N LC1G3D3T LC1G3D3N LC1G3D2T LC1G3D2N LC1G3D1T

LC1G3D1N

xxxx xxxx uuuu uuuu

F17h

CLC1GLS3

LC1G4D4T LC1G4D4N LC1G4D3T LC1G4D3N LC1G4D2T LC1G4D2N LC1G4D1T

LC1G4D1N

xxxx xxxx uuuu uuuu

F18h

CLC2CON

LC2EN

LC2OE

LC2OUT

LC2INTP

F19h

CLC2POL

LC2POL

F1Ah

CLC2SEL0

LC2D2S<2:0>

LC2D1S<2:0>

F1Bh

CLC2SEL1

LC2D4S<2:0>

LC2D3S<2:0>

F1Ch

CLC2GLS0

LC2G1D4T LC2G1D4N LC2G1D3T LC2G1D3N LC2G1D2T LC2G1D2N LC2G1D1T

LC2G1D1N

xxxx xxxx uuuu uuuu

F1Dh

CLC2GLS1

LC2G2D4T LC2G2D4N LC2G2D3T LC2G2D3N LC2G2D2T LC2G2D2N LC2G2D1T

LC2G2D1N

xxxx xxxx uuuu uuuu

F1Eh

CLC2GLS2

LC2G3D4T LC2G3D4N LC2G3D3T LC2G3D3N LC2G3D2T LC2G3D2N LC2G3D1T

LC2G3D1N

xxxx xxxx uuuu uuuu

F1Fh

CLC2GLS3

LC2G4D4T LC2G4D4N LC2G4D3T LC2G4D3N LC2G4D2T LC2G4D2N LC2G4D1T

LC2G4D1N

xxxx xxxx uuuu uuuu

F20h

CLC3CON

LC3EN

LC3OE

LC3OUT

LC3INTP

F21h

CLC3POL

LC3POL

F22h

CLC3SEL0

LC3D2S<2:0>

LC3D1S<2:0>

F23h

CLC3SEL1

LC3D4S<2:0>

LC3D3S<2:0>

F24h

CLC3GLS0

LC3G1D4T LC3G1D4N LC3G1D3T LC3G1D3N LC3G1D2T LC3G1D2N LC3G1D1T

LC3G1D1N

xxxx xxxx uuuu uuuu

F25h

CLC3GLS1

LC3G2D4T LC3G2D4N LC3G2D3T LC3G2D3N LC3G2D2T LC3G2D2N LC3G2D1T

LC3G2D1N

xxxx xxxx uuuu uuuu

F26h

CLC3GLS2

LC3G3D4T LC3G3D4N LC3G3D3T LC3G3D3N LC3G3D2T LC3G3D2N LC3G3D1T

LC3G3D1N

xxxx xxxx uuuu uuuu

F27h

CLC3GLS3

LC3G4D4T LC3G4D4N LC3G4D3T LC3G4D3N LC3G4D2T LC3G4D2N LC3G4D1T

LC3G4D1N

xxxx xxxx uuuu uuuu

F28h

CLC4CON

LC4EN

LC4OE

LC4OUT

LC4INTP

F29h

CLC4POL

LC4POL

F2Ah

CLC4SEL0

LC4D2S<2:0>

LC4D1S<2:0>

F2Bh

CLC4SEL1

LC4D4S<2:0>

LC4D3S<2:0>

F2Ch

CLC4GLS0

LC4G1D4T LC4G1D4N LC4G1D3T LC4G1D3N LC4G1D2T LC4G1D2N LC4G1D1T

LC4G1D1N

xxxx xxxx uuuu uuuu

F2Dh

CLC4GLS1

LC4G2D4T LC4G2D4N LC4G2D3T LC4G2D3N LC4G2D2T LC4G2D2N LC4G2D1T

LC4G2D1N

xxxx xxxx uuuu uuuu

F2Eh

CLC4GLS2

LC4G3D4T LC4G3D4N LC4G3D3T LC4G3D3N LC4G3D2T LC4G3D2N LC4G3D1T

LC4G3D1N

xxxx xxxx uuuu uuuu

F2Fh

CLC4GLS3

LC4G4D4T LC4G4D4N LC4G4D3T LC4G4D3N LC4G4D2T LC4G4D2N LC4G4D1T

LC4G4D1N

xxxx xxxx uuuu uuuu

Unimplemented

F30h
to
F6Fh

MLC4OUT MLC3OUT
LC1INTN

MLC2OUT

LC1G4POL LC1G3POL LC1G2POL

LC2INTN

LC4INTN

-xxx -xxx -uuu -uuu

0000 0000 0000 0000

LC2G1POL

0--- xxxx 0--- uuuu

-xxx -xxx -uuu -uuu
-xxx -xxx -uuu -uuu

0000 0000 0000 0000

LC3G1POL

0--- xxxx 0--- uuuu

-xxx -xxx -uuu -uuu
-xxx -xxx -uuu -uuu

LC4MODE<2:0>

LC4G4POL LC4G3POL LC4G2POL

0--- xxxx 0--- uuuu

-xxx -xxx -uuu -uuu

LC3MODE<2:0>

LC3G4POL LC3G3POL LC3G2POL

---- 0000 ---- 0000

0000 0000 0000 0000

LC1G1POL

LC2MODE<2:0>

LC2G4POL LC2G3POL LC2G2POL

LC3INTN

MLC1OUT

LC1MODE<2:0>

0000 0000 0000 0000

LC4G1POL

0--- xxxx 0--- uuuu

-xxx -xxx -uuu -uuu
-xxx -xxx -uuu -uuu

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 33

PIC16(L)F1508/9
TABLE 3-9:
Address

Name

SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Value on
POR, BOR

Value on all
other
Resets

Bank 31
F8Ch

FE3h

FE4h

STATUS_

Unimplemented

Z_SHAD

DC_SHAD

C_SHAD

---- -xxx ---- -uuu

SHAD
FE5h

WREG_

Working Register Shadow

xxxx xxxx uuuu uuuu

SHAD
FE6h

BSR_

Bank Select Register Shadow

---x xxxx ---u uuuu

SHAD
FE7h

PCLATH_

Program Counter Latch High Register Shadow

-xxx xxxx uuuu uuuu

SHAD
FE8h

FSR0L_

Indirect Data Memory Address 0 Low Pointer Shadow

xxxx xxxx uuuu uuuu

Indirect Data Memory Address 0 High Pointer Shadow

xxxx xxxx uuuu uuuu

Indirect Data Memory Address 1 Low Pointer Shadow

xxxx xxxx uuuu uuuu

Indirect Data Memory Address 1 High Pointer Shadow

xxxx xxxx uuuu uuuu

SHAD
FE9h

FSR0H_
SHAD

FEAh

FSR1L_
SHAD

FEBh

FSR1H_
SHAD

FECh

FEDh

STKPTR

FEEh

TOSL

FEFh

TOSH

Unimplemented

Current Stack Pointer

Top-of-Stack Low byte

---1 1111 ---1 1111

xxxx xxxx uuuu uuuu

Top-of-Stack High byte

-xxx xxxx -uuu uuuu

DS41609A-page 34

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
3.3

PCL and PCLATH

3.3.2

The Program Counter (PC) is 15 bits wide. The low byte

comes from the PCL register, which is a readable and
writable register. The high byte (PC<14:8>) is not directly
readable or writable and comes from PCLATH. On any
Reset, the PC is cleared. Figure 3-4 shows the five
situations for the loading of the PC.

FIGURE 3-4:

LOADING OF PC IN
DIFFERENT SITUATIONS
PCH

PCL

PC
6

PCLATH

Instruction with
PCL as
Destination

ALU Result

PCH

PCL

PC
6 4

PCLATH

GOTO, CALL

PCH

PCL

CALLW

PCH

PCL

BRW
15

PC + W

PCH

PCL

If using BRW, load the W register with the desired

unsigned address and execute BRW. The entire PC will
be loaded with the address PC + 1 + W.

BRA
15

PC + OPCODE <8:0>

3.3.1

BRANCHING

The branching instructions add an offset to the PC.

This allows relocatable code and code that crosses
page boundaries. There are two forms of branching,
BRW and BRA. The PC will have incremented to fetch
the next instruction in both cases. When using either
branching instruction, a PCL memory boundary may be
crossed.

COMPUTED FUNCTION CALLS

A computed function CALL allows programs to maintain

tables of functions and provide another way to execute
state machines or look-up tables. When performing a
table read using a computed function CALL, care
should be exercised if the table location crosses a PCL
memory boundary (each 256-byte block).

3.3.4

PCLATH

3.3.3

The CALLW instruction enables computed calls by combining PCLATH and W to form the destination address.
A computed CALLW is accomplished by loading the W
register with the desired address and executing CALLW.
The PCL register is loaded with the value of W and
PCH is loaded with PCLATH.

OPCODE <10:0>

A computed GOTO is accomplished by adding an offset to

the program counter (ADDWF PCL). When performing a
table read using a computed GOTO method, care should
be exercised if the table location crosses a PCL memory
boundary (each 256-byte block). Refer to Application
Note AN556, Implementing a Table Read (DS00556).

If using the CALL instruction, the PCH<2:0> and PCL

registers are loaded with the operand of the CALL
instruction. PCH<6:3> is loaded with PCLATH<6:3>.

COMPUTED GOTO

If using BRA, the entire PC will be loaded with PC + 1 +,

the signed value of the operand of the BRA instruction.

MODIFYING PCL

Executing any instruction with the PCL register as the

destination simultaneously causes the Program Counter PC<14:8> bits (PCH) to be replaced by the contents
of the PCLATH register. This allows the entire contents
of the program counter to be changed by writing the
desired upper 7 bits to the PCLATH register. When the
lower 8 bits are written to the PCL register, all 15 bits of
the program counter will change to the values contained in the PCLATH register and those being written
to the PCL register.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 35

PIC16(L)F1508/9
3.4

Stack

3.4.1

The stack is available through the TOSH, TOSL and

STKPTR registers. STKPTR is the current value of the
Stack Pointer. TOSH:TOSL register pair points to the
TOP of the stack. Both registers are read/writable. TOS
is split into TOSH and TOSL due to the 15-bit size of the
PC. To access the stack, adjust the value of STKPTR,
which will position TOSH:TOSL, then read/write to
TOSH:TOSL. STKPTR is 5 bits to allow detection of
overflow and underflow.

All devices have a 16-level x 15-bit wide hardware

stack (refer to Figures 3-5 through 3-8). The stack
space is not part of either program or data space. The
PC is PUSHed onto the stack when CALL or CALLW
instructions are executed or an interrupt causes a
branch. The stack is POPed in the event of a RETURN,
RETLW or a RETFIE instruction execution. PCLATH is
not affected by a PUSH or POP operation.
The stack operates as a circular buffer if the STVREN
bit is programmed to 0 (Configuration Words). This
means that after the stack has been PUSHed sixteen
times, the seventeenth PUSH overwrites the value that
was stored from the first PUSH. The eighteenth PUSH
overwrites the second PUSH (and so on). The
STKOVF and STKUNF flag bits will be set on an Overflow/Underflow, regardless of whether the Reset is
enabled.

Note:

Care should be taken when modifying the

STKPTR while interrupts are enabled.

During normal program operation, CALL, CALLW and

Interrupts will increment STKPTR while RETLW,
RETURN, and RETFIE will decrement STKPTR. At any
time STKPTR can be inspected to see how much stack
is left. The STKPTR always points at the currently used
place on the stack. Therefore, a CALL or CALLW will
increment the STKPTR and then write the PC, and a
return will unload the PC and then decrement the
STKPTR.

Note 1: There are no instructions/mnemonics

called PUSH or POP. These are actions
that occur from the execution of the
CALL, CALLW, RETURN, RETLW and
RETFIE instructions or the vectoring to
an interrupt address.

FIGURE 3-5:

ACCESSING THE STACK

Reference Figure 3-5 through Figure 3-8 for examples

of accessing the stack.

ACCESSING THE STACK EXAMPLE 1

TOSH:TOSL

0x0F

STKPTR = 0x1F

Stack Reset Disabled

(STVREN = 0)

0x0E
0x0D
0x0C
0x0B
0x0A

Initial Stack Configuration:

0x09

After Reset, the stack is empty. The

empty stack is initialized so the Stack
Pointer is pointing at 0x1F. If the Stack
Overflow/Underflow Reset is enabled, the
TOSH/TOSL registers will return 0. If
the Stack Overflow/Underflow Reset is
disabled, the TOSH/TOSL registers will
return the contents of stack address 0x0F.

0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
0x00
TOSH:TOSL

DS41609A-page 36

0x1F

0x0000

Preliminary

STKPTR = 0x1F

Stack Reset Enabled

(STVREN = 1)

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 3-6:

ACCESSING THE STACK EXAMPLE 2

0x0F
0x0E
0x0D
0x0C
0x0B
0x0A
0x09

This figure shows the stack configuration

after the first CALL or a single interrupt.
If a RETURN instruction is executed, the
return address will be placed in the
Program Counter and the Stack Pointer
decremented to the empty state (0x1F).

0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
TOSH:TOSL

FIGURE 3-7:

0x00

Return Address

STKPTR = 0x00

ACCESSING THE STACK EXAMPLE 3

0x0F
0x0E
0x0D
0x0C

After seven CALLs or six CALLs and an

interrupt, the stack looks like the figure
on the left. A series of RETURN instructions
will repeatedly place the return addresses
into the Program Counter and pop the stack.

0x0B
0x0A
0x09
0x08
0x07
TOSH:TOSL

2011 Microchip Technology Inc.

0x06

Return Address

0x05

Return Address

0x04

Return Address

0x03

Return Address

0x02

Return Address

0x01

Return Address

0x00

Return Address

Preliminary

STKPTR = 0x06

DS41609A-page 37

PIC16(L)F1508/9
FIGURE 3-8:

ACCESSING THE STACK EXAMPLE 4

TOSH:TOSL

3.4.2

0x0F

Return Address

0x0E

Return Address

0x0D

Return Address

0x0C

Return Address

0x0B

Return Address

0x0A

Return Address

0x09

Return Address

0x08

Return Address

0x07

Return Address

0x06

Return Address

0x05

Return Address

0x04

Return Address

0x03

Return Address

0x02

Return Address

0x01

Return Address

0x00

Return Address

When the stack is full, the next CALL or

an interrupt will set the Stack Pointer to
0x10. This is identical to address 0x00
so the stack will wrap and overwrite the
return address at 0x00. If the Stack
Overflow/Underflow Reset is enabled, a
Reset will occur and location 0x00 will
not be overwritten.

STKPTR = 0x10

OVERFLOW/UNDERFLOW RESET

If the STVREN bit in Configuration Words is

programmed to 1, the device will be reset if the stack
is PUSHed beyond the sixteenth level or POPed
beyond the first level, setting the appropriate bits
(STKOVF or STKUNF, respectively) in the PCON
register.

3.5

Indirect Addressing

The INDFn registers are not physical registers. Any

instruction that accesses an INDFn register actually
accesses the register at the address specified by the
File Select Registers (FSR). If the FSRn address
specifies one of the two INDFn registers, the read will
return 0 and the write will not occur (though Status bits
may be affected). The FSRn register value is created
by the pair FSRnH and FSRnL.
The FSR registers form a 16-bit address that allows an
addressing space with 65536 locations. These locations
are divided into three memory regions:
Traditional Data Memory
Linear Data Memory
Program Flash Memory

DS41609A-page 38

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 3-9:

INDIRECT ADDRESSING
0x0000

0x0000

Traditional
Data Memory

0x0FFF

0x0FFF
0x1000

Reserved

0x1FFF
0x2000

Linear
Data Memory

0x29AF
0x29B0
FSR
Address
Range

Reserved

0x7FFF
0x8000

0x0000

Program
Flash Memory

0xFFFF

Note:

0x7FFF

Not all memory regions are completely implemented. Consult device memory tables for memory limits.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 39

PIC16(L)F1508/9
3.5.1

TRADITIONAL DATA MEMORY

The traditional data memory is a region from FSR

address 0x000 to FSR address 0xFFF. The addresses
correspond to the absolute addresses of all SFR, GPR
and common registers.

FIGURE 3-10:

TRADITIONAL DATA MEMORY MAP

Direct Addressing
4

BSR

Indirect Addressing

From Opcode

7
0

Bank Select

Location Select
0x00

FSRxH
0

FSRxL

0
Bank Select

00000 00001 00010

11111

Bank 0 Bank 1 Bank 2

Bank 31

Location Select

0x7F

DS41609A-page 40

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
3.5.2

3.5.3

LINEAR DATA MEMORY

The linear data memory is the region from FSR

address 0x2000 to FSR address 0x29AF. This region is
a virtual region that points back to the 80-byte blocks of
GPR memory in all the banks.
Unimplemented memory reads as 0x00. Use of the
linear data memory region allows buffers to be larger
than 80 bytes because incrementing the FSR beyond
one bank will go directly to the GPR memory of the next
bank.
The 16 bytes of common memory are not included in
the linear data memory region.

FIGURE 3-11:

7
FSRnH
0 0 1

LINEAR DATA MEMORY

MAP
0

FSRnL

To make constant data access easier, the entire

program Flash memory is mapped to the upper half of
the FSR address space. When the MSB of FSRnH is
set, the lower 15 bits are the address in program
memory which will be accessed through INDF. Only the
lower 8 bits of each memory location is accessible via
INDF. Writing to the program Flash memory cannot be
accomplished via the FSR/INDF interface. All
instructions that access program Flash memory via the
FSR/INDF interface will require one additional
instruction cycle to complete.

FIGURE 3-12:
7
1

PROGRAM FLASH MEMORY

FSRnH

PROGRAM FLASH
MEMORY MAP
0

Location Select
Location Select

0x2000

FSRnL

0x8000

0x0000

0x020
Bank 0
0x06F
0x0A0
Bank 1
0x0EF
0x120

Program
Flash
Memory
(low 8
bits)

Bank 2
0x16F

0xF20
Bank 30
0x29AF

2011 Microchip Technology Inc.

0xF6F

Preliminary

0xFFFF

0x7FFF

DS41609A-page 41

PIC16(L)F1508/9
NOTES:

DS41609A-page 42

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
4.0

DEVICE CONFIGURATION

Device configuration consists of Configuration Words,

Code Protection and Device ID.

4.1

Configuration Words

There are several Configuration Word bits that allow

different oscillator and memory protection options.
These are implemented as Configuration Word 1 at
8007h and Configuration Word 2 at 8008h.
Note:

The DEBUG bit in Configuration Words is

managed
automatically
by
device
development tools including debuggers
and programmers. For normal device
operation, this bit should be maintained as
a '1'.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 43

PIC16(L)F1508/9
REGISTER 4-1:

CONFIG1: CONFIGURATION WORD 1

R/P-1

FCMEN

IESO

CLKOUTEN

R/P-1

BOREN<1:0>

U-1

bit 13
R/P-1

R/P-1

MCLRE

PWRTE

bit 8
R/P-1

R/P-1

WDTE<1:0>

R/P-1

FOSC<2:0>

bit 7

bit 0

Legend:
R = Readable bit

P = Programmable bit

U = Unimplemented bit, read as 1

0 = Bit is cleared

1 = Bit is set

-n = Value when blank or after Bulk Erase

bit 13

FCMEN: Fail-Safe Clock Monitor Enable bit

1 = Fail-Safe Clock Monitor is enabled
0 = Fail-Safe Clock Monitor is disabled

bit 12

IESO: Internal External Switchover bit

1 = Internal/External Switchover mode is enabled
0 = Internal/External Switchover mode is disabled

bit 11

CLKOUTEN: Clock Out Enable bit

1 = CLKOUT function is disabled. I/O function on the CLKOUT pin
0 = CLKOUT function is enabled on the CLKOUT pin

bit 10-9

BOREN<1:0>: Brown-out Reset Enable bits(1)

11 = BOR enabled
10 = BOR enabled during operation and disabled in Sleep
01 = BOR controlled by SBOREN bit of the BORCON register
00 = BOR disabled

bit 8

Unimplemented: Read as 1

bit 7

CP: Code Protection bit(2)

1 = Program memory code protection is disabled
0 = Program memory code protection is enabled

bit 6

MCLRE: MCLR/VPP Pin Function Select bit

If LVP bit = 1:
This bit is ignored.
If LVP bit = 0:
1 = MCLR/VPP pin function is MCLR; Weak pull-up enabled.
0 = MCLR/VPP pin function is digital input; MCLR internally disabled; Weak pull-up under control of
WPUE3 bit.

bit 5

PWRTE: Power-Up Timer Enable bit

1 = PWRT disabled
0 = PWRT enabled

bit 4-3

WDTE<1:0>: Watchdog Timer Enable bits

11 = WDT enabled
10 = WDT enabled while running and disabled in Sleep
01 = WDT controlled by the SWDTEN bit in the WDTCON register
00 = WDT disabled

bit 2-0

FOSC<2:0>: Oscillator Selection bits

111 = ECH:External clock, High-Power mode: on CLKIN pin
110 = ECM: External clock, Medium-Power mode: on CLKIN pin
101 = ECL: External clock, Low-Power mode: on CLKIN pin
100 = INTOSC oscillator: I/O function on CLKIN pin
011 = EXTRC oscillator: External RC circuit connected to CLKIN pin
010 = HS oscillator: High-speed crystal/resonator connected between OSC1 and OSC2 pins
001 = XT oscillator: Crystal/resonator connected between OSC1 and OSC2 pins
000 = LP oscillator: Low-power crystal connected between OSC1 and OSC2 pins

Note

1:
2:

Enabling Brown-out Reset does not automatically enable Power-up Timer.

Once enabled, code-protect can only be disabled by bulk erasing the device.

DS41609A-page 44

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 4-2:

CONFIG2: CONFIGURATION WORD 2

R/P-1
LVP

R/P-1
DEBUG

(3)

R/P-1

U-1

LPBOR

BORV

STVREN

bit 13

bit 8

U-1

R/P-1

WRT<1:0>

bit 7

bit 0

Legend:
R = Readable bit

P = Programmable bit

U = Unimplemented bit, read as 1

0 = Bit is cleared

1 = Bit is set

-n = Value when blank or after Bulk Erase

bit 13

LVP: Low-Voltage Programming Enable bit(1)

1 = Low-voltage programming enabled
0 = High-voltage on MCLR must be used for programming

bit 12

DEBUG: In-Circuit Debugger Mode bit(3)

1 = In-Circuit Debugger disabled, ICSPCLK and ICSPDAT are general purpose I/O pins
0 = In-Circuit Debugger enabled, ICSPCLK and ICSPDAT are dedicated to the debugger

bit 11

LPBOR: Low-Power BOR Enable bit

1 = Low-Power Brown-out Reset is disabled
0 = Low-Power Brown-out Reset is enabled

bit 10

BORV: Brown-out Reset Voltage Selection bit(2)

1 = Brown-out Reset voltage (Vbor), low trip point selected.
0 = Brown-out Reset voltage (Vbor), high trip point selected.

bit 9

STVREN: Stack Overflow/Underflow Reset Enable bit

1 = Stack Overflow or Underflow will cause a Reset
0 = Stack Overflow or Underflow will not cause a Reset

bit 8-2

Unimplemented: Read as 1

bit 1-0

WRT<1:0>: Flash Memory Self-Write Protection bits

2 kW Flash memory:
11 = Write protection off
10 = 000h to 1FFh write-protected, 200h to 7FFh may be modified
01 = 000h to 3FFh write-protected, 400h to 7FFh may be modified
00 = 000h to 7FFh write-protected, no addresses may be modified

Note 1:
2:
3:

The LVP bit cannot be programmed to 0 when Programming mode is entered via LVP.
See Vbor parameter for specific trip point voltages.
The DEBUG bit in Configuration Words is managed automatically by device development tools including
debuggers and programmers. For normal device operation, this bit should be maintained as a '1'.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 45

PIC16(L)F1508/9
4.2

Code Protection

Code protection allows the device to be protected from

unauthorized access. Internal access to the program
memory is unaffected by any code protection setting.

4.2.1

PROGRAM MEMORY PROTECTION

The entire program memory space is protected from

external reads and writes by the CP bit in Configuration
Words. When CP = 0, external reads and writes of
program memory are inhibited and a read will return all
0s. The CPU can continue to read program memory,
regardless of the protection bit settings. Writing the
program memory is dependent upon the write
protection
setting.
See
Section 4.3
Write
Protection for more information.

4.3

Write Protection

Write protection allows the device to be protected from

unintended self-writes. Applications, such as
bootloader software, can be protected while allowing
other regions of the program memory to be modified.
The WRT<1:0> bits in Configuration Words define the
size of the program memory block that is protected.

4.4

User ID

Four memory locations (8000h-8003h) are designated as

ID locations where the user can store checksum or other
code identification numbers. These locations are
readable and writable during normal execution. See
Section 10.4 User ID, Device ID and Configuration
Word Access for more information on accessing these
memory locations. For more information on checksum
calculation, see the PIC12(L)F1501/PIC16(L)F150X
Memory Programming Specification (DS41573).

DS41609A-page 46

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
4.5

Device ID and Revision ID

The memory location 8006h is where the Device ID and

Revision ID are stored. The upper nine bits hold the
Device ID. The lower five bits hold the Revision ID. See
Section 10.4 User ID, Device ID and Configuration
Word Access for more information on accessing
these memory locations.
Development tools, such as device programmers and
debuggers, may be used to read the Device ID and
Revision ID.

DEVICEID: DEVICE ID REGISTER

DEV<8:3>
bit 13
R

bit 8
R

DEV<2:0>

REV<4:0>

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 1

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

P = Programmable bit

bit 13-5

DEV<8:0>: Device ID bits

Device

bit 4-0

DEVICEID<13:0> Values
DEV<8:0>

REV<4:0>

PIC16F1508

10 1101 001

x xxxx

PIC16LF1508

10 1101 111

x xxxx

PIC16F1509

10 1101 010

x xxxx

PIC16LF1509

10 1101 000

x xxxx

REV<4:0>: Revision ID bits

These bits are used to identify the revision (see Table under DEV<8:0> above).

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 47

PIC16(L)F1508/9
NOTES:

DS41609A-page 48

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
5.0

OSCILLATOR MODULE (WITH

FAIL-SAFE CLOCK MONITOR)

5.1

Overview

The oscillator module has a wide variety of clock

sources and selection features that allow it to be used
in a wide range of applications while maximizing performance and minimizing power consumption. Figure 5-1
illustrates a block diagram of the oscillator module.
Clock sources can be supplied from external oscillators,
quartz crystal resonators, ceramic resonators and
Resistor-Capacitor (RC) circuits. In addition, the system
clock source can be supplied from one of two internal
oscillators, with a choice of speeds selectable via
software. Additional clock features include:
Selectable system clock source between external
or internal sources via software.
Two-Speed Start-up mode, which minimizes
latency between external oscillator start-up and
code execution.
Fail-Safe Clock Monitor (FSCM) designed to
detect a failure of the external clock source (LP,
XT, HS, EC or RC modes) and switch
automatically to the internal oscillator.
Oscillator Start-up Timer (OST) ensures stability
of crystal oscillator sources
Fast start-up oscillator allows internal circuits to
power-up and stabilize before switching to the 16
MHz HFINTOSC

2011 Microchip Technology Inc.

The oscillator module can be configured in one of eight

clock modes.
1.
2.
3.
4.
5.
6.
7.
8.

ECL External Clock Low-Power mode

(0 MHz to 0.5 MHz)
ECM External Clock Medium-Power mode
(0.5 MHz to 4 MHz)
ECH External Clock High-Power mode
(4 MHz to 20 MHz)
LP 32 kHz Low-Power Crystal mode.
XT Medium Gain Crystal or Ceramic Resonator
Oscillator mode (up to 4 MHz)
HS High Gain Crystal or Ceramic Resonator
mode (4 MHz to 20 MHz)
RC External Resistor-Capacitor (RC)
INTOSC Internal oscillator (31 kHz to 16 MHz)

Clock Source modes are selected by the FOSC<2:0>

bits in the Configuration Words. The FOSC bits
determine the type of oscillator that will be used when
the device is first powered.
The EC clock mode relies on an external logic level
signal as the device clock source. The LP, XT, and HS
clock modes require an external crystal or resonator to
be connected to the device. Each mode is optimized for
a different frequency range. The RC clock mode
requires an external resistor and capacitor to set the
oscillator frequency.
The INTOSC internal oscillator block produces a low
and high-frequency clock source, designated
LFINTOSC and HFINTOSC. (See Internal Oscillator
Block, Figure 5-1). A wide selection of device clock
frequencies may be derived from these two clock
sources.

Preliminary

DS41609A-page 49

PIC16(L)F1508/9
FIGURE 5-1:

SIMPLIFIED PIC MCU CLOCK SOURCE BLOCK DIAGRAM

CLKIN/ OSC1/
SOSCI/ T1CKI
Primary Clock

Primary
Oscillator
(OSC)

Sleep
Secondary Clock

Secondary
Oscillator
(SOSC)

IRCF<3:0>

CPU and

MUX

CLKOUT / OSC2
SOSCO/ T1G

Peripherals

INTOSC

16 MHz
Primary OSC
Start-Up
OSC

31 kHz
Source

DS41609A-page 50

Postscaler

Start-up
Control Logic

MUX

4
16 MHz
8 MHz
4 MHz
2 MHz
1 MHz
500 kHz
250 kHz
125 kHz
62.5 kHz
31.25 kHz
31 kHz

Clock
Control
3
FOSC<2:0>

2
SCS<1:0>

WDT, PWRT and other Modules

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
5.2

Clock Source Types

Clock sources can be classified as external or internal.

External clock sources rely on external circuitry for the
clock source to function. Examples are: oscillator modules (EC mode), quartz crystal resonators or ceramic
resonators (LP, XT and HS modes) and Resistor-Capacitor (RC) mode circuits.
Internal clock sources are contained within the oscillator
module. The internal oscillator block has two internal
oscillators that are used to generate the internal system
clock sources: the 16 MHz High-Frequency Internal
Oscillator and the 31 kHz Low-Frequency Internal
Oscillator (LFINTOSC).

The Oscillator Start-up Timer (OST) is disabled when

EC mode is selected. Therefore, there is no delay in
operation after a Power-on Reset (POR) or wake-up
from Sleep. Because the PIC MCU design is fully
static, stopping the external clock input will have the
effect of halting the device while leaving all data intact.
Upon restarting the external clock, the device will
resume operation as if no time had elapsed.

FIGURE 5-2:

5.2.1

An external clock source can be used as the device

system clock by performing one of the following
actions:
Program the FOSC<2:0> bits in the Configuration
Words to select an external clock source that will
be used as the default system clock upon a
device Reset.
Write the SCS<1:0> bits in the OSCCON register
to switch the system clock source to:
- Secondary oscillator during run-time, or
- An external clock source determined by the
value of the FOSC bits.
See Section 5.3 Clock Switchingfor more information.

5.2.1.1

EC Mode

The External Clock (EC) mode allows an externally

generated logic level signal to be the system clock
source. When operating in this mode, an external clock
source is connected to the OSC1 input.
OSC2/CLKOUT is available for general purpose I/O or
CLKOUT. Figure 5-2 shows the pin connections for EC
mode.
EC mode has 3 power modes to select from through
Configuration Words:

PIC MCU

FOSC/4 or I/O(1)
Note 1:

EXTERNAL CLOCK SOURCES

OSC1/CLKIN

Clock from
Ext. System

The system clock can be selected between external or

internal clock sources via the System Clock Select
(SCS) bits in the OSCCON register. See Section 5.3
Clock Switching for additional information.

5.2.1.2

EXTERNAL CLOCK (EC)

MODE OPERATION

OSC2/CLKOUT

Output depends upon CLKOUTEN bit of the

Configuration Words.

LP, XT, HS Modes

The LP, XT and HS modes support the use of quartz

crystal resonators or ceramic resonators connected to
OSC1 and OSC2 (Figure 5-3). The three modes select
a low, medium or high gain setting of the internal
inverter-amplifier to support various resonator types
and speed.
LP Oscillator mode selects the lowest gain setting of the
internal inverter-amplifier. LP mode current consumption
is the least of the three modes. This mode is designed to
drive only 32.768 kHz tuning-fork type crystals (watch
crystals).
XT Oscillator mode selects the intermediate gain
setting of the internal inverter-amplifier. XT mode
current consumption is the medium of the three modes.
This mode is best suited to drive resonators with a
medium drive level specification.
HS Oscillator mode selects the highest gain setting of the
internal inverter-amplifier. HS mode current consumption
is the highest of the three modes. This mode is best
suited for resonators that require a high drive setting.
Figure 5-3 and Figure 5-4 show typical circuits for
quartz crystal and ceramic resonators, respectively.

High power, 4-20 MHz (FOSC = 111)

Medium power, 0.5-4 MHz (FOSC = 110)
Low power, 0-0.5 MHz (FOSC = 101)

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 51

PIC16(L)F1508/9
FIGURE 5-3:

QUARTZ CRYSTAL
OPERATION (LP, XT OR
HS MODE)

FIGURE 5-4:

CERAMIC RESONATOR
OPERATION
(XT OR HS MODE)

PIC MCU

OSC1/CLKIN
C1

To Internal
Logic
Quartz
Crystal

OSC1/CLKIN

RS(1)

RF(2)

Sleep

RP(3)

OSC2/CLKOUT

A series resistor (RS) may be required for

quartz crystals with low drive level.

The value of RF varies with the Oscillator mode

selected (typically between 2 M to 10 M.

DS41609A-page 52

RF(2)

C2 Ceramic
RS(1)
Resonator

Note 1:

AN826, Crystal Oscillator Basics and

Crystal Selection for rfPIC and PIC
Devices (DS00826)
AN849, Basic PIC Oscillator Design
(DS00849)
AN943, Practical PIC Oscillator
Analysis and Design (DS00943)
AN949, Making Your Oscillator Work
(DS00949)

To Internal
Logic

Note 1:

Sleep

OSC2/CLKOUT

A series resistor (RS) may be required for

ceramic resonators with low drive level.

2: The value of RF varies with the Oscillator mode

selected (typically between 2 M to 10 M.
3: An additional parallel feedback resistor (RP)
may be required for proper ceramic resonator
operation.

5.2.1.3

Oscillator Start-up Timer (OST)

If the oscillator module is configured for LP, XT or HS

modes, the Oscillator Start-up Timer (OST) counts
1024 oscillations from OSC1. This occurs following a
Power-on Reset (POR) and when the Power-up Timer
(PWRT) has expired (if configured), or a wake-up from
Sleep. During this time, the program counter does not
increment and program execution is suspended. The
OST ensures that the oscillator circuit, using a quartz
crystal resonator or ceramic resonator, has started and
is providing a stable system clock to the oscillator
module.
In order to minimize latency between external oscillator
start-up and code execution, the Two-Speed Clock
Start-up mode can be selected (see Section 5.4
Two-Speed Clock Start-up Mode).

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
5.2.1.4

5.2.1.5

Secondary Oscillator

External RC Mode

The secondary oscillator is a separate crystal oscillator

that is associated with the Timer1 peripheral. It is optimized for timekeeping operations with a 32.768 kHz
crystal connected between the SOSCO and SOSCI
device pins.

The external Resistor-Capacitor (RC) modes support

the use of an external RC circuit. This allows the
designer maximum flexibility in frequency choice while
keeping costs to a minimum when clock accuracy is not
required.

The secondary oscillator can be used as an alternate

system clock source and can be selected during
run-time using clock switching. Refer to Section 5.3
Clock Switching for more information.

The RC circuit connects to OSC1. OSC2/CLKOUT is

available for general purpose I/O or CLKOUT. The
function of the OSC2/CLKOUT pin is determined by the
CLKOUTEN bit in Configuration Words.

FIGURE 5-5:

Figure 5-6 shows the external RC mode connections.

QUARTZ CRYSTAL
OPERATION
(SECONDARY
OSCILLATOR)

FIGURE 5-6:
VDD

OSC1/CLKIN

SOSCI

VSS
FOSC/4 or I/O(1)

SOSCO

OSC2/CLKOUT

Recommended values: 10 k REXT 100 k, <3V

3 k REXT 100 k, 3-5V
CEXT > 20 pF, 2-5V

Note 1: Quartz
crystal
characteristics
vary
according to type, package and
manufacturer. The user should consult the
manufacturer data sheets for specifications
and recommended application.
2: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
3: For oscillator design assistance, reference
the following Microchip Applications Notes:
AN826, Crystal Oscillator Basics and
Crystal Selection for rfPIC and PIC
Devices (DS00826)
AN849, Basic PIC Oscillator Design
(DS00849)
AN943, Practical PIC Oscillator
Analysis and Design (DS00943)
AN949, Making Your Oscillator Work
(DS00949)
TB097, Interfacing a Micro Crystal
MS1V-T1K 32.768 kHz Tuning Fork
Crystal to a PIC16F690/SS (DS91097)
AN1288, Design Practices for
Low-Power External Oscillators
(DS01288)

2011 Microchip Technology Inc.

Internal
Clock

CEXT
To Internal
Logic

32.768 kHz
Quartz
Crystal

PIC MCU

REXT

PIC MCU

EXTERNAL RC MODES

Note 1:

Output depends upon CLKOUTEN bit of the

Configuration Words.

The RC oscillator frequency is a function of the supply

voltage, the resistor (REXT) and capacitor (CEXT) values
and the operating temperature. Other factors affecting
the oscillator frequency are:
threshold voltage variation
component tolerances
packaging variations in capacitance
The user also needs to take into account variation due
to tolerance of external RC components used.

Preliminary

DS41609A-page 53

PIC16(L)F1508/9
5.2.2

INTERNAL CLOCK SOURCES

5.2.2.2

The device may be configured to use the internal oscillator block as the system clock by performing one of the
following actions:
Program the FOSC<2:0> bits in Configuration
Words to select the INTOSC clock source, which
will be used as the default system clock upon a
device Reset.
Write the SCS<1:0> bits in the OSCCON register
to switch the system clock source to the internal
oscillator during run-time. See Section 5.3
Clock Switchingfor more information.
In INTOSC mode, OSC1/CLKIN is available for general
purpose I/O. OSC2/CLKOUT is available for general
purpose I/O or CLKOUT.
The function of the OSC2/CLKOUT pin is determined
by the CLKOUTEN bit in Configuration Words.
The internal oscillator block has two independent
oscillators that provides the internal system clock
source.
1.

The HFINTOSC (High-Frequency Internal

Oscillator) is factory calibrated and operates at
16 MHz.
The LFINTOSC (Low-Frequency Internal
Oscillator) is uncalibrated and operates at
31 kHz.

5.2.2.1

HFINTOSC

The High-Frequency Internal Oscillator (HFINTOSC) is

a factory calibrated 16 MHz internal clock source.

LFINTOSC

The Low-Frequency Internal Oscillator (LFINTOSC) is

an uncalibrated 31 kHz internal clock source.
The output of the LFINTOSC connects to a postscaler
and multiplexer (see Figure 5-1). Select 31 kHz, via
software, using the IRCF<3:0> bits of the OSCCON
register. See Section 5.2.2.4 Internal Oscillator
Clock Switch Timing for more information. The
LFINTOSC is also the frequency for the Power-up Timer
(PWRT), Watchdog Timer (WDT) and Fail-Safe Clock
Monitor (FSCM).
The LFINTOSC is enabled by selecting 31 kHz
(IRCF<3:0> bits of the OSCCON register = 000) as the
system clock source (SCS bits of the OSCCON
register = 1x), or when any of the following are
enabled:
Configure the IRCF<3:0> bits of the OSCCON
register for the desired LF frequency, and
FOSC<2:0> = 100, or
Set the System Clock Source (SCS) bits of the
OSCCON register to 1x
Peripherals that use the LFINTOSC are:
Power-up Timer (PWRT)
Watchdog Timer (WDT)
Fail-Safe Clock Monitor (FSCM)
The Low-Frequency Internal Oscillator Ready bit
(LFIOFR) of the OSCSTAT register indicates when the
LFINTOSC is running.

The output of the HFINTOSC connects to a postscaler

and multiplexer (see Figure 5-1). The frequency derived
from the HFINTOSC can be selected via software using
the IRCF<3:0> bits of the OSCCON register. See
Section 5.2.2.4 Internal Oscillator Clock Switch
Timing for more information.
The HFINTOSC is enabled by:
Configure the IRCF<3:0> bits of the OSCCON
register for the desired HF frequency, and
FOSC<2:0> = 100, or
Set the System Clock Source (SCS) bits of the
OSCCON register to 1x.
A fast start-up oscillator allows internal circuits to
power-up and stabilize before switching to HFINTOSC.
The High-Frequency Internal Oscillator Ready bit
(HFIOFR) of the OSCSTAT register indicates when the
HFINTOSC is running.
The High-Frequency Internal Oscillator Stable bit
(HFIOFS) of the OSCSTAT register indicates when the
HFINTOSC is running within 0.5% of its final value.

DS41609A-page 54

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
5.2.2.3

Internal Oscillator Frequency

Selection

5.2.2.4

The system clock speed can be selected via software

using the Internal Oscillator Frequency Select bits
IRCF<3:0> of the OSCCON register.
The output of the 16 MHz HFINTOSC and 31 kHz
LFINTOSC connects to a postscaler and multiplexer
(see Figure 5-1). The Internal Oscillator Frequency
Select bits IRCF<3:0> of the OSCCON register select
the frequency output of the internal oscillators. One of
the following frequencies can be selected via software:

Note:

2.
3.
4.

5.
6.
7.

IRCF<3:0> bits of the OSCCON register are

modified.
If the new clock is shut down, a clock start-up
delay is started.
Clock switch circuitry waits for a falling edge of
the current clock.
The current clock is held low and the clock
switch circuitry waits for a rising edge in the new
clock.
The new clock is now active.
The OSCSTAT register is updated as required.
Clock switch is complete.

See Figure 5-7 for more details.

Following any Reset, the IRCF<3:0> bits

of the OSCCON register are set to 0111
and the frequency selection is set to
500 kHz. The user can modify the IRCF
bits to select a different frequency.

The IRCF<3:0> bits of the OSCCON register allow

duplicate selections for some frequencies. These duplicate choices can offer system design trade-offs. Lower
power consumption can be obtained when changing
oscillator sources for a given frequency. Faster transition times can be obtained between frequency changes
that use the same oscillator source.

2011 Microchip Technology Inc.

When switching between the HFINTOSC and the

LFINTOSC, the new oscillator may already be shut
down to save power (see Figure 5-7). If this is the case,
there is a delay after the IRCF<3:0> bits of the
OSCCON register are modified before the frequency
selection takes place. The OSCSTAT register will
reflect the current active status of the HFINTOSC and
LFINTOSC oscillators. The sequence of a frequency
selection is as follows:
1.

HFINTOSC
- 16 MHz
- 8 MHz
- 4 MHz
- 2 MHz
- 1 MHz
- 500 kHz (default after Reset)
- 250 kHz
- 125 kHz
- 62.5 kHz
- 31.25 kHz
LFINTOSC
- 31 kHz

Internal Oscillator Clock Switch

Timing

If the internal oscillator speed is switched between two

clocks of the same source, there is no start-up delay
before the new frequency is selected. Clock switching
time delays are shown in Table 5-1.
Start-up delay specifications are located in the
oscillator tables of Section 29.0 Electrical
Specifications.

Preliminary

DS41609A-page 55

PIC16(L)F1508/9
FIGURE 5-7:

HFINTOSC

INTERNAL OSCILLATOR SWITCH TIMING

LFINTOSC (FSCM and WDT disabled)

HFINTOSC
Start-up Time

2-cycle Sync

Running

LFINTOSC
IRCF <3:0>

System Clock

HFINTOSC

LFINTOSC (Either FSCM or WDT enabled)

HFINTOSC
2-cycle Sync

Running

LFINTOSC

IRCF <3:0>

System Clock

LFINTOSC

HFINTOSC

LFINTOSC turns off unless WDT or FSCM is enabled

LFINTOSC
Start-up Time

2-cycle Sync

Running

HFINTOSC
IRCF <3:0>

System Clock

DS41609A-page 56

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
5.3

Clock Switching

5.3.3

SECONDARY OSCILLATOR

The system clock source can be switched between

external and internal clock sources via software using
the System Clock Select (SCS) bits of the OSCCON
register. The following clock sources can be selected
using the SCS bits:

The secondary oscillator is a separate crystal oscillator

associated with the Timer1 peripheral. It is optimized
for timekeeping operations with a 32.768 kHz crystal
connected between the SOSCO and SOSCI device
pins.

Default system oscillator determined by FOSC

bits in Configuration Words
Secondary oscillator 32 kHz crystal
Internal Oscillator Block (INTOSC)

The secondary oscillator is enabled using the

T1OSCEN control bit in the T1CON register. See
Section 19.0 Timer1 Module with Gate Control for
more information about the Timer1 peripheral.

5.3.1

5.3.4

SYSTEM CLOCK SELECT (SCS)

BITS

The System Clock Select (SCS) bits of the OSCCON

register selects the system clock source that is used for
the CPU and peripherals.
When the SCS bits of the OSCCON register = 00,
the system clock source is determined by value of
the FOSC<2:0> bits in the Configuration Words.
When the SCS bits of the OSCCON register = 01,
the system clock source is the secondary
oscillator.
When the SCS bits of the OSCCON register = 1x,
the system clock source is chosen by the internal
oscillator frequency selected by the IRCF<3:0>
bits of the OSCCON register. After a Reset, the
SCS bits of the OSCCON register are always
cleared.
Note:

SECONDARY OSCILLATOR READY

(SOSCR) BIT

The user must ensure that the secondary oscillator is

ready to be used before it is selected as a system clock
source. The Secondary Oscillator Ready (SOSCR) bit
of the OSCSTAT register indicates whether the
secondary oscillator is ready to be used. After the
SOSCR bit is set, the SCS bits can be configured to
select the secondary oscillator.

Any automatic clock switch, which may

occur from Two-Speed Start-up or
Fail-Safe Clock Monitor, does not update
the SCS bits of the OSCCON register. The
user can monitor the OSTS bit of the
OSCSTAT register to determine the current
system clock source.

When switching between clock sources, a delay is

required to allow the new clock to stabilize. These oscillator delays are shown in Table 5-1.

5.3.2

OSCILLATOR START-UP TIME-OUT

STATUS (OSTS) BIT

The Oscillator Start-up Time-out Status (OSTS) bit of

the OSCSTAT register indicates whether the system
clock is running from the external clock source, as
defined by the FOSC<2:0> bits in the Configuration
Words, or from the internal clock source. In particular,
OSTS indicates that the Oscillator Start-up Timer
(OST) has timed out for LP, XT or HS modes. The OST
does not reflect the status of the secondary oscillator.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 57

PIC16(L)F1508/9
5.4

Two-Speed Clock Start-up Mode

5.4.1

Two-Speed Start-up mode provides additional power

savings by minimizing the latency between external
oscillator start-up and code execution. In applications
that make heavy use of the Sleep mode, Two-Speed
Start-up will remove the external oscillator start-up
time from the time spent awake and can reduce the
overall power consumption of the device. This mode
allows the application to wake-up from Sleep, perform
a few instructions using the INTOSC internal oscillator
block as the clock source and go back to Sleep without
waiting for the external oscillator to become stable.
Two-Speed Start-up provides benefits when the oscillator module is configured for LP, XT, or HS modes.
The Oscillator Start-up Timer (OST) is enabled for
these modes and must count 1024 oscillations before
the oscillator can be used as the system clock source.

TWO-SPEED START-UP MODE

CONFIGURATION

Two-Speed Start-up mode is configured by the

following settings:
IESO (of the Configuration Words) = 1; Internal/External Switchover bit (Two-Speed Start-up
mode enabled).
SCS (of the OSCCON register) = 00.
FOSC<2:0> bits in the Configuration Words
configured for LP, XT or HS mode.
Two-Speed Start-up mode is entered after:
Power-on Reset (POR) and, if enabled, after
Power-up Timer (PWRT) has expired, or
Wake-up from Sleep.

If the oscillator module is configured for any mode

other than LP, XT or HS mode, then Two-Speed
Start-up is disabled. This is because the external clock
oscillator does not require any stabilization time after
POR or an exit from Sleep.
If the OST count reaches 1024 before the device
enters Sleep mode, the OSTS bit of the OSCSTAT register is set and program execution switches to the
external oscillator. However, the system may never
operate from the external oscillator if the time spent
awake is very short.
Note:

Executing a SLEEP instruction will abort

the oscillator start-up time and will cause
the OSTS bit of the OSCSTAT register to
remain clear.

TABLE 5-1:

OSCILLATOR SWITCHING DELAYS

Switch From

Switch To

Frequency

Oscillator Delay

Sleep/POR

LFINTOSC
HFINTOSC

31 kHz
31.25 kHz-16 MHz

Oscillator Warm-up Delay (TWARM)

Sleep/POR

EC, RC

DC 20 MHz

2 cycles

LFINTOSC

EC, RC

DC 20 MHz

1 cycle of each

Sleep/POR

Secondary Oscillator,
32 kHz-20 MHz
LP, XT, HS

1024 Clock Cycles (OST)

Any clock source

HFINTOSC

31.25 kHz-16 MHz

2 s (approx.)

Any clock source

LFINTOSC

31 kHz

1 cycle of each

Any clock source

Secondary Oscillator 32 kHz

DS41609A-page 58

Preliminary

1024 Clock Cycles (OST)

2011 Microchip Technology Inc.

PIC16(L)F1508/9
5.4.2
1.
2.

3.
4.
5.
6.
7.

TWO-SPEED START-UP
SEQUENCE

5.4.3

Wake-up from Power-on Reset or Sleep.

Instructions begin execution by the internal
oscillator at the frequency set in the IRCF<3:0>
bits of the OSCCON register.
OST enabled to count 1024 clock cycles.
OST timed out, wait for falling edge of the
internal oscillator.
OSTS is set.
System clock held low until the next falling edge
of new clock (LP, XT or HS mode).
System clock is switched to external clock
source.

FIGURE 5-8:

CHECKING TWO-SPEED CLOCK

STATUS

Checking the state of the OSTS bit of the OSCSTAT

register will confirm if the microcontroller is running
from the external clock source, as defined by the
FOSC<2:0> bits in the Configuration Words, or the
internal oscillator.

TWO-SPEED START-UP

INTOSC
TOST
OSC1

1022 1023

OSC2
Program Counter

PC - N

PC + 1

System Clock

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 59

PIC16(L)F1508/9
5.5

Fail-Safe Clock Monitor

5.5.3

The Fail-Safe Clock Monitor (FSCM) allows the device

to continue operating should the external oscillator fail.
The FSCM can detect oscillator failure any time after
the Oscillator Start-up Timer (OST) has expired. The
FSCM is enabled by setting the FCMEN bit in the
Configuration Words. The FSCM is applicable to all
external Oscillator modes (LP, XT, HS, EC, RC and
secondary oscillator).

FIGURE 5-9:

FSCM BLOCK DIAGRAM

External
Clock

LFINTOSC
Oscillator

31 kHz
(~32 s)

488 Hz
(~2 ms)

Sample Clock

5.5.1

The Fail-Safe condition is cleared after a Reset,

executing a SLEEP instruction or changing the SCS bits
of the OSCCON register. When the SCS bits are
changed, the OST is restarted. While the OST is
running, the device continues to operate from the
INTOSC selected in OSCCON. When the OST times
out, the Fail-Safe condition is cleared and the device
will be operating from the external clock source. The
Fail-Safe condition must be cleared before the OSFIF
flag can be cleared.

5.5.4

Clock Monitor
Latch

RESET OR WAKE-UP FROM SLEEP

The FSCM is designed to detect an oscillator failure

after the Oscillator Start-up Timer (OST) has expired.
The OST is used after waking up from Sleep and after
any type of Reset. The OST is not used with the EC or
RC Clock modes so that the FSCM will be active as
soon as the Reset or wake-up has completed. When
the FSCM is enabled, the Two-Speed Start-up is also
enabled. Therefore, the device will always be executing
code while the OST is operating.
Clock
Failure
Detected

Note:

FAIL-SAFE DETECTION

The FSCM module detects a failed oscillator by

comparing the external oscillator to the FSCM sample
clock. The sample clock is generated by dividing the
LFINTOSC by 64. See Figure 5-9. Inside the fail
detector block is a latch. The external clock sets the
latch on each falling edge of the external clock. The
sample clock clears the latch on each rising edge of the
sample clock. A failure is detected when an entire
half-cycle of the sample clock elapses before the
external clock goes low.

5.5.2

FAIL-SAFE CONDITION CLEARING

Due to the wide range of oscillator start-up

times, the Fail-Safe circuit is not active
during oscillator start-up (i.e., after exiting
Reset or Sleep). After an appropriate
amount of time, the user should check the
Status bits in the OSCSTAT register to
verify the oscillator start-up and that the
system clock switchover has successfully
completed.

FAIL-SAFE OPERATION

When the external clock fails, the FSCM switches the

device clock to an internal clock source and sets the bit
flag OSFIF of the PIR2 register. Setting this flag will
generate an interrupt if the OSFIE bit of the PIE2
register is also set. The device firmware can then take
steps to mitigate the problems that may arise from a
failed clock. The system clock will continue to be
sourced from the internal clock source until the device
firmware successfully restarts the external oscillator
and switches back to external operation.
The internal clock source chosen by the FSCM is
determined by the IRCF<3:0> bits of the OSCCON
register. This allows the internal oscillator to be
configured before a failure occurs.

DS41609A-page 60

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 5-10:

FSCM TIMING DIAGRAM

Sample Clock
Oscillator
Failure

System
Clock
Output
Clock Monitor Output
(Q)

Failure
Detected

OSCFIF

Test
Note:

Test

The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in
this example have been chosen for clarity.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 61

PIC16(L)F1508/9
5.6

Oscillator Control Registers

OSCCON: OSCILLATOR CONTROL REGISTER

R/W-0/0

R/W-1/1

IRCF<3:0>

U-0

R/W-0/0

SCS<1:0>

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

Unimplemented: Read as 0

bit 6-3

IRCF<3:0>: Internal Oscillator Frequency Select bits

1111 = 16 MHz
1110 = 8 MHz
1101 = 4 MHz
1100 = 2 MHz
1011 = 1 MHz
1010 = 500 kHz(1)
1001 = 250 kHz(1)
1000 = 125 kHz(1)
0111 = 500 kHz (default upon Reset)
0110 = 250 kHz
0101 = 125 kHz
0100 = 62.5 kHz
001x = 31.25 kHz
000x = 31 kHz LF

bit 2

Unimplemented: Read as 0

bit 1-0

SCS<1:0>: System Clock Select bits

1x = Internal oscillator block
01 = Secondary oscillator
00 = Clock determined by FOSC<2:0> in Configuration Words.

Note 1:

Duplicate frequency derived from HFINTOSC.

DS41609A-page 62

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 5-2:

OSCSTAT: OSCILLATOR STATUS REGISTER

R-1/q

U-0

R-q/q

R-0/q

U-0

R-0/q

SOSCR

OSTS

HFIOFR

LFIOFR

HFIOFS

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Conditional

bit 7

SOSCR: Secondary Oscillator Ready bit

If T1OSCEN = 1:
1 = Secondary oscillator is ready
0 = Secondary oscillator is not ready
If T1OSCEN = 0:
1 = Timer1 clock source is always ready

bit 6

Unimplemented: Read as 0

bit 5

OSTS: Oscillator Start-up Time-out Status bit

1 = Running from the clock defined by the FOSC<2:0> bits of the Configuration Words
0 = Running from an internal oscillator (FOSC<2:0> = 100)

bit 4

HFIOFR: High-Frequency Internal Oscillator Ready bit

1 = HFINTOSC is ready
0 = HFINTOSC is not ready

bit 3-2

Unimplemented: Read as 0

bit 1

LFIOFR: Low-Frequency Internal Oscillator Ready bit

1 = LFINTOSC is ready
0 = LFINTOSC is not ready

bit 0

HFIOFS: High-Frequency Internal Oscillator Stable bit

1 = HFINTOSC 16 MHz Oscillator is stable and is driving the INTOSC
0 = HFINTOSC 16 MHz is not stable, the Start-up Oscillator is driving INTOSC

TABLE 5-2:

SUMMARY OF REGISTERS ASSOCIATED WITH CLOCK SOURCES

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

OSCCON

OSCSTAT

SOSCR

OSTS

HFIOFR

LFIOFR

HFIOFS

PIE2

OSFIE

C2IE

C1IE

BCL1IE

NCO1IE

PIR2

OSFIF

C2IF

C1IF

BCL1IF

NCO1IF

T1OSCEN

T1SYNC

TMR1ON

175

TMR1CS<1:0>

T1CON
Legend:

CONFIG1
Legend:

T1CKPS<1:0>

SCS<1:0>

= unimplemented location, read as 0. Shaded cells are not used by clock sources.

TABLE 5-3:
Name

IRCF<3:0>

Bits

SUMMARY OF CONFIGURATION WORD WITH CLOCK SOURCES

Bit -/7

Bit -/6

Bit 13/5

Bit 12/4

Bit 11/3

IESO

CLKOUTEN

13:8

FCMEN

7:0

MCLRE

PWRTE

Bit 10/2

Bit 9/1

BOREN<1:0>

WDTE<1:0>

FOSC<2:0>

Bit 8/0

= unimplemented location, read as 0. Shaded cells are not used by clock sources.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 63

PIC16(L)F1508/9
NOTES:

DS41609A-page 64

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
6.0

RESETS

There are multiple ways to reset this device:

Power-on Reset (POR)

Brown-out Reset (BOR)
Low-Power Brown-out Reset (LPBOR)
MCLR Reset
WDT Reset
RESET instruction
Stack Overflow
Stack Underflow
Programming mode exit

To allow VDD to stabilize, an optional Power-up Timer

can be enabled to extend the Reset time after a BOR
or POR event.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 6-1.

FIGURE 6-1:

SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT

ICSP Programming Mode Exit

RESET Instruction
Stack
Pointer

MCLRE
MCLR

Sleep

WDT
Time-out

Device
Reset

Power-on
Reset
VDD

Brown-out
Reset

PWRT
Done

LPBOR
Reset

PWRTE
LFINTOSC
BOR
Active(1)

Note 1:

See Table 6-1 for BOR active conditions.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 65

PIC16(L)F1508/9
6.1

Power-on Reset (POR)

6.2

Brown-Out Reset (BOR)

The POR circuit holds the device in Reset until VDD has
reached an acceptable level for minimum operation.
Slow rising VDD, fast operating speeds or analog
performance may require greater than minimum VDD.
The PWRT, BOR or MCLR features can be used to
extend the start-up period until all device operation
conditions have been met.

The BOR circuit holds the device in Reset when VDD

reaches a selectable minimum level. Between the
POR and BOR, complete voltage range coverage for
execution protection can be implemented.

6.1.1

POWER-UP TIMER (PWRT)

The Power-up Timer provides a nominal 64 ms timeout on POR or Brown-out Reset.

The device is held in Reset as long as PWRT is active.
The PWRT delay allows additional time for the VDD to
rise to an acceptable level. The Power-up Timer is
enabled by clearing the PWRTE bit in Configuration
Words.
The Power-up Timer starts after the release of the POR
and BOR.
For additional information, refer to Application Note
AN607, Power-up Trouble Shooting (DS00607).

TABLE 6-1:

The Brown-out Reset module has four operating

modes controlled by the BOREN<1:0> bits in Configuration Words. The four operating modes are:
BOR is always on
BOR is off when in Sleep
BOR is controlled by software
BOR is always off

Refer to Table 6-1 for more information.

The Brown-out Reset voltage level is selectable by
configuring the BORV bit in Configuration Words.
A VDD noise rejection filter prevents the BOR from triggering on small events. If VDD falls below VBOR for a
duration greater than parameter TBORDC, the device
will reset. See Figure 6-2 for more information.

BOR OPERATING MODES

Instruction Execution upon:
Release of POR or Wake-up from Sleep

BOREN<1:0>

SBOREN

Device Mode

BOR Mode

Active

Waits for BOR ready(1)

(BORRDY = 1)

Awake

Active

Sleep

Disabled

Waits for BOR ready

(BORRDY = 1)

1
01
00

Active

Waits for BOR ready(1)

(BORRDY = 1)
Begins immediately
(BORRDY = x)

Disabled

Note 1: In these specific cases, release of POR and wake-up from Sleep, there is no delay in start-up. The BOR
ready flag, (BORRDY = 1), will be set before the CPU is ready to execute instructions because the BOR
circuit is forced on by the BOREN<1:0> bits.

6.2.1

BOR IS ALWAYS ON

When the BOREN bits of Configuration Words are programmed to 11, the BOR is always on. The device
start-up will be delayed until the BOR is ready and VDD
is higher than the BOR threshold.
BOR protection is active during Sleep. The BOR does
not delay wake-up from Sleep.

6.2.2

BOR IS OFF IN SLEEP

When the BOREN bits of Configuration Words are programmed to 10, the BOR is on, except in Sleep. The
device start-up will be delayed until the BOR is ready
and VDD is higher than the BOR threshold.

DS41609A-page 66

BOR protection is not active during Sleep. The device

wake-up will be delayed until the BOR is ready.

6.2.3

BOR CONTROLLED BY SOFTWARE

When the BOREN bits of Configuration Words are

programmed to 01, the BOR is controlled by the
SBOREN bit of the BORCON register. The device
start-up is not delayed by the BOR ready condition or
the VDD level.
BOR protection begins as soon as the BOR circuit is
ready. The status of the BOR circuit is reflected in the
BORRDY bit of the BORCON register.
BOR protection is unchanged by Sleep.

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 6-2:

BROWN-OUT SITUATIONS
VDD

VBOR

Internal
Reset

TPWRT(1)

VDD

VBOR

Internal
Reset

< TPWRT

TPWRT(1)

VDD

VBOR

Internal
Reset

Note 1:

TPWRT(1)

TPWRT delay only if PWRTE bit is programmed to 0.

BORCON: BROWN-OUT RESET CONTROL REGISTER

R/W-1/u

R/W-0/u

U-0

R-q/u

SBOREN

BORFS

BORRDY

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7

SBOREN: Software Brown-out Reset Enable bit

If BOREN <1:0> in Configuration Words 01:
SBOREN is read/write, but has no effect on the BOR.
If BOREN <1:0> in Configuration Words = 01:
1 = BOR Enabled
0 = BOR Disabled

bit 6

BORFS: Brown-out Reset Fast Start bit(1)

If BOREN<1:0> = 11 (Always on) or BOREN<1:0> = 00 (Always off)
BORFS is Read/Write, but has no effect.
If BOREN <1:0> = 10 (Disabled in Sleep) or BOREN<1:0> = 01 (Under software control):
1 = Band gap is forced on always (covers sleep/wake-up/operating cases)
0 = Band gap operates normally, and may turn off

bit 5-1

Unimplemented: Read as 0

bit 0

BORRDY: Brown-out Reset Circuit Ready Status bit

1 = The Brown-out Reset circuit is active
0 = The Brown-out Reset circuit is inactive

Note 1:

BOREN<1:0> bits are located in Configuration Words.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 67

PIC16(L)F1508/9
6.3

Low-Power Brown-out Reset

(LPBOR)

6.5

The Low-Power Brown-Out Reset (LPBOR) is an

essential part of the Reset subsystem. Refer to
Figure 6-1 to see how the BOR interacts with other
modules.
The LPBOR is used to monitor the external VDD pin.
When too low of a voltage is detected, the device is
held in Reset. When this occurs, a register bit (BOR) is
changed to indicate that a BOR Reset has occurred.
The same bit is set for both the BOR and the LPBOR.
Refer to Register 6-2.

6.3.1

ENABLING LPBOR

The LPBOR is controlled by the LPBOR bit of

Configuration Words. When the device is erased, the
LPBOR module defaults to disabled.

6.3.1.1

LPBOR Module Output

The output of the LPBOR module is a signal indicating

whether or not a Reset is to be asserted. This signal is
ORd together with the Reset signal of the BOR module to provide the generic BOR signal which goes to
the PCON register and to the power control block.

6.4

MCLR

Watchdog Timer (WDT) Reset

The Watchdog Timer generates a Reset if the firmware

does not issue a CLRWDT instruction within the time-out
period. The TO and PD bits in the STATUS register are
changed to indicate the WDT Reset. See Section 9.0
Watchdog Timer for more information.

6.6

RESET Instruction

A RESET instruction will cause a device Reset. The RI

bit in the PCON register will be set to 0. See Table 6-4
for default conditions after a RESET instruction has
occurred.

6.7

Stack Overflow/Underflow Reset

The device can reset when the Stack Overflows or

Underflows. The STKOVF or STKUNF bits of the PCON
register indicate the Reset condition. These Resets are
enabled by setting the STVREN bit in Configuration
Words. See Section 3.4.2 Overflow/Underflow
Reset for more information.

6.8

Programming Mode Exit

Upon exit of Programming mode, the device will

behave as if a POR had just occurred.

The MCLR is an optional external input that can reset

the device. The MCLR function is controlled by the
MCLRE bit of Configuration Words and the LVP bit of
Configuration Words (Table 6-2).

6.9

TABLE 6-2:

The Power-up Timer is controlled by the PWRTE bit of

Configuration Words.

MCLR CONFIGURATION

MCLRE

LVP

MCLR

Disabled

Enabled

6.4.1

MCLR ENABLED

A Reset does not drive the MCLR pin low.

MCLR DISABLED

When MCLR is disabled, the pin functions as a general

purpose input and the internal weak pull-up is under
software control. See Section 11.2 PORTA Registers for more information.

DS41609A-page 68

Start-up Sequence

Upon the release of a POR or BOR, the following must

occur before the device will begin executing:

The device has a noise filter in the MCLR Reset path.

The filter will detect and ignore small pulses.

6.4.2

The Power-up Timer optionally delays device execution

after a BOR or POR event. This timer is typically used to
allow VDD to stabilize before allowing the device to start
running.

6.10

When MCLR is enabled and the pin is held low, the

device is held in Reset. The MCLR pin is connected to
VDD through an internal weak pull-up.

Note:

Power-Up Timer

1.
2.

Power-up Timer runs to completion (if enabled).

MCLR must be released (if enabled).

The total time-out will vary based on oscillator configuration and Power-up Timer configuration. See
Section 5.0 Oscillator Module (With Fail-Safe
Clock Monitor) for more information.
The Power-up Timer runs independently of MCLR
Reset. If MCLR is kept low long enough, the Power-up
Timer will expire. Upon bringing MCLR high, the device
will begin execution immediately (see Figure 6-3). This
is useful for testing purposes or to synchronize more
than one device operating in parallel.

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 6-3:

RESET START-UP SEQUENCE

VDD
Internal POR
TPWRT
Power-Up Timer
MCLR
TMCLR
Internal RESET

Internal Oscillator
Oscillator
FOSC

External Clock (EC)

CLKIN

FOSC

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 69

PIC16(L)F1508/9
6.11

Determining the Cause of a Reset

Upon any Reset, multiple bits in the STATUS and

PCON registers are updated to indicate the cause of
the Reset. Table 6-3 and Table 6-4 show the Reset
conditions of these registers.

TABLE 6-3:

RESET STATUS BITS AND THEIR SIGNIFICANCE

STKOVF STKUNF RWDT

RMCLR

POR

BOR

Condition

Power-on Reset

Illegal, TO is set on POR

Illegal, PD is set on POR

Brown-out Reset

WDT Reset

WDT Wake-up from Sleep

Interrupt Wake-up from Sleep

MCLR Reset during normal operation

MCLR Reset during Sleep

RESET Instruction Executed

Stack Overflow Reset (STVREN = 1)

Stack Underflow Reset (STVREN = 1)

TABLE 6-4:

RESET CONDITION FOR SPECIAL REGISTERS(2)

Program
Counter

STATUS
Register

PCON
Register

Power-on Reset

0000h

---1 1000

00-- 110x

MCLR Reset during normal operation

0000h

---u uuuu

uu-- 0uuu

MCLR Reset during Sleep

0000h

---1 0uuu

uu-- 0uuu

WDT Reset

0000h

---0 uuuu

uu-- uuuu

WDT Wake-up from Sleep

PC + 1

---0 0uuu

uu-- uuuu

Brown-out Reset

0000h

---1 1uuu

00-- 11u0

---1 0uuu

uu-- uuuu

---u uuuu

uu-- u0uu

Condition

Interrupt Wake-up from Sleep

RESET Instruction Executed

PC + 1

(1)

0000h

Stack Overflow Reset (STVREN = 1)

0000h

---u uuuu

1u-- uuuu

Stack Underflow Reset (STVREN = 1)

0000h

---u uuuu

u1-- uuuu

Legend: u = unchanged, x = unknown, - = unimplemented bit, reads as 0.

Note 1: When the wake-up is due to an interrupt and Global Interrupt Enable bit (GIE) is set, the return address is
pushed on the stack and PC is loaded with the interrupt vector (0004h) after execution of PC + 1.
2: If a Status bit is not implemented, that bit will be read as 0.

DS41609A-page 70

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
6.12

Power Control (PCON) Register

The Power Control (PCON) register contains flag bits

to differentiate between a:

Power-on Reset (POR)

Brown-out Reset (BOR)
Reset Instruction Reset (RI)
MCLR Reset (RMCLR)
Watchdog Timer Reset (RWDT)
Stack Underflow Reset (STKUNF)
Stack Overflow Reset (STKOVF)

The PCON register bits are shown in Register 6-2.

PCON: POWER CONTROL REGISTER

R/W/HS-0/q

U-0

STKOVF

STKUNF

R/W/HC-1/q R/W/HC-1/q
RWDT

R/W/HC-1/q

R/W/HC-q/u

POR

BOR

RMCLR

bit 7

bit 0

Legend:
HC = Bit is cleared by hardware

HS = Bit is set by hardware

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7

STKOVF: Stack Overflow Flag bit

1 = A Stack Overflow occurred
0 = A Stack Overflow has not occurred or cleared by firmware

bit 6

STKUNF: Stack Underflow Flag bit

1 = A Stack Underflow occurred
0 = A Stack Underflow has not occurred or cleared by firmware

bit 5

Unimplemented: Read as 0

bit 4

RWDT: Watchdog Timer Reset Flag bit

1 = A Watchdog Timer Reset has not occurred or set by firmware
0 = A Watchdog Timer Reset has occurred (cleared by hardware)

bit 3

RMCLR: MCLR Reset Flag bit

1 = A MCLR Reset has not occurred or set by firmware
0 = A MCLR Reset has occurred (cleared by hardware)

bit 2

RI: RESET Instruction Flag bit

1 = A RESET instruction has not been executed or set by firmware
0 = A RESET instruction has been executed (cleared by hardware)

bit 1

POR: Power-on Reset Status bit

1 = No Power-on Reset occurred
0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)

bit 0

BOR: Brown-out Reset Status bit

1 = No Brown-out Reset occurred
0 = A Brown-out Reset occurred (must be set in software after a Power-on Reset or Brown-out Reset
occurs)

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DS41609A-page 71

PIC16(L)F1508/9
TABLE 6-5:

SUMMARY OF REGISTERS ASSOCIATED WITH RESETS

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

BORCON

SBOREN

BORFS

BORRDY

PCON

STKOVF

STKUNF

RWDT

RMCLR

POR

BOR

STATUS

WDTCON

SWDTEN

WDTPS<4:0>

Legend: = unimplemented bit, reads as 0. Shaded cells are not used by Resets.
Note 1: Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.

TABLE 6-6:
Name
CONFIG1
CONFIG2

Legend:

Bits

SUMMARY OF CONFIGURATION WORD WITH RESETS

Bit -/7

Bit -/6

Bit 13/5

Bit 12/4

Bit 11/3

CLKOUTEN

Bit 10/2

13:8

7:0

MCLRE

PWRTE

13:8

LVP

DEBUG

LPBOR

BORV

7:0

Bit 9/1

BOREN<1:0>

WDTE<1:0>

Bit 8/0

FOSC<2:0>

STVREN

WRT<1:0>

= unimplemented location, read as 0. Shaded cells are not used by Resets.

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Preliminary

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PIC16(L)F1508/9
7.0

INTERRUPTS

The interrupt feature allows certain events to preempt

normal program flow. Firmware is used to determine
the source of the interrupt and act accordingly. Some
interrupts can be configured to wake the MCU from
Sleep mode.
This chapter contains the following information for
Interrupts:

Operation
Interrupt Latency
Interrupts During Sleep
INT Pin
Automatic Context Saving

Many peripherals produce interrupts. Refer to the

corresponding chapters for details.
A block diagram of the interrupt logic is shown in
Figure 7-1.

FIGURE 7-1:

INTERRUPT LOGIC

TMR0IF
TMR0IE

Peripheral Interrupts
(TMR1IF) PIR1<0>
(TMR1IF) PIR1<0>

Wake-up
(If in Sleep mode)

INTF
INTE
IOCIF
IOCIE

Interrupt
to CPU

PEIE
PIRn<7>
PIEn<7>

2011 Microchip Technology Inc.

GIE

Preliminary

DS41609A-page 73

PIC16(L)F1508/9
7.1

Operation

7.2

Interrupts are disabled upon any device Reset. They

are enabled by setting the following bits:
GIE bit of the INTCON register
Interrupt Enable bit(s) for the specific interrupt
event(s)
PEIE bit of the INTCON register (if the Interrupt
Enable bit of the interrupt event is contained in the
PIE1, PIE2 and PIE3 registers)

Interrupt Latency

Interrupt latency is defined as the time from when the

interrupt event occurs to the time code execution at the
interrupt vector begins. The latency for synchronous
interrupts is 3 or 4 instruction cycles. For asynchronous
interrupts, the latency is 3 to 5 instruction cycles,
depending on when the interrupt occurs. See Figure 7-2
and Figure 7.3 for more details.

The INTCON, PIR1, PIR2 and PIR3 registers record

individual interrupts via interrupt flag bits. Interrupt flag
bits will be set, regardless of the status of the GIE, PEIE
and individual interrupt enable bits.
The following events happen when an interrupt event
occurs while the GIE bit is set:
Current prefetched instruction is flushed
GIE bit is cleared
Current Program Counter (PC) is pushed onto the
stack
Critical registers are automatically saved to the
Shadow registers (See Section 7.5 Automatic
Context Saving.)
PC is loaded with the interrupt vector 0004h
The firmware within the Interrupt Service Routine (ISR)
should determine the source of the interrupt by polling
the interrupt flag bits. The interrupt flag bits must be
cleared before exiting the ISR to avoid repeated
interrupts. Because the GIE bit is cleared, any interrupt
that occurs while executing the ISR will be recorded
through its interrupt flag, but will not cause the
processor to redirect to the interrupt vector.
The RETFIE instruction exits the ISR by popping the
previous address from the stack, restoring the saved
context from the Shadow registers and setting the GIE
bit.
For additional information on a specific interrupts
operation, refer to its peripheral chapter.
Note 1: Individual interrupt flag bits are set,
regardless of the state of any other
enable bits.
2: All interrupts will be ignored while the GIE
bit is cleared. Any interrupt occurring
while the GIE bit is clear will be serviced
when the GIE bit is set again.

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PIC16(L)F1508/9
FIGURE 7-2:

INTERRUPT LATENCY

Fosc
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

CLKR

Interrupt Sampled
during Q1

Interrupt
GIE

PC
Execute

PC-1

1 Cycle Instruction at PC

PC+1

0004h

0005h

Inst(PC)

NOP

Inst(0004h)

PC+1/FSR
ADDR

New PC/
PC+1

0004h

0005h

Inst(PC)

NOP

Inst(0004h)

FSR ADDR

PC+1

PC+2

0004h

0005h

INST(PC)

NOP

Inst(0004h)

Inst(0005h)

FSR ADDR

PC+1

0004h

0005h

INST(PC)

NOP

Inst(0004h)

Interrupt
GIE

PC
Execute

PC-1

2 Cycle Instruction at PC

Interrupt
GIE

PC
Execute

PC-1

3 Cycle Instruction at PC

Interrupt
GIE

PC
Execute

PC-1

3 Cycle Instruction at PC

2011 Microchip Technology Inc.

Preliminary

PC+2
NOP

NOP

DS41609A-page 75

PIC16(L)F1508/9
FIGURE 7-3:

INT PIN INTERRUPT TIMING

FOSC
CLKOUT

(3)

INT pin

(1)
(1)

INTF

Interrupt Latency (2)

(4)

GIE

INSTRUCTION FLOW
PC
Instruction
Fetched
Instruction
Executed

Note 1:

Inst (PC)
Inst (PC 1)

PC + 1
Inst (PC + 1)
Inst (PC)

PC + 1

Forced NOP

0004h

0005h

Inst (0004h)

Inst (0005h)

Forced NOP

Inst (0004h)

INTF flag is sampled here (every Q1).

Asynchronous interrupt latency = 3-5 TCY. Synchronous latency = 3-4 TCY, where TCY = instruction cycle time.
Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction.

For minimum width of INT pulse, refer to AC specifications in Section 29.0 Electrical Specifications.

INTF is enabled to be set any time during the Q4-Q1 cycles.

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PIC16(L)F1508/9
7.3

Interrupts During Sleep

Some interrupts can be used to wake from Sleep. To

wake from Sleep, the peripheral must be able to
operate without the system clock. The interrupt source
must have the appropriate Interrupt Enable bit(s) set
prior to entering Sleep.
On waking from Sleep, if the GIE bit is also set, the
processor will branch to the interrupt vector. Otherwise,
the processor will continue executing instructions after
the SLEEP instruction. The instruction directly after the
SLEEP instruction will always be executed before
branching to the ISR. Refer to Section 8.0 PowerDown Mode (Sleep) for more details.

7.4

INT Pin

The INT pin can be used to generate an asynchronous

edge-triggered interrupt. This interrupt is enabled by
setting the INTE bit of the INTCON register. The
INTEDG bit of the OPTION_REG register determines on
which edge the interrupt will occur. When the INTEDG
bit is set, the rising edge will cause the interrupt. When
the INTEDG bit is clear, the falling edge will cause the
interrupt. The INTF bit of the INTCON register will be set
when a valid edge appears on the INT pin. If the GIE and
INTE bits are also set, the processor will redirect
program execution to the interrupt vector.

7.5

Automatic Context Saving

Upon entering an interrupt, the return PC address is

saved on the stack. Additionally, the following registers
are automatically saved in the Shadow registers:

W register
STATUS register (except for TO and PD)
BSR register
FSR registers
PCLATH register

Upon exiting the Interrupt Service Routine, these registers are automatically restored. Any modifications to
these registers during the ISR will be lost. If modifications to any of these registers are desired, the corresponding Shadow register should be modified and the
value will be restored when exiting the ISR. The
Shadow registers are available in Bank 31 and are
readable and writable. Depending on the users application, other registers may also need to be saved.

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Preliminary

DS41609A-page 77

PIC16(L)F1508/9
7.6

Interrupt Control Registers

7.6.1

Note:

INTCON REGISTER

The INTCON register is a readable and writable

register, that contains the various enable and flag bits
for TMR0 register overflow, interrupt-on-change and
external INT pin interrupts.

Interrupt flag bits are set when an interrupt

condition occurs, regardless of the state of
its corresponding enable bit or the Global
Interrupt Enable bit, GIE, of the INTCON
register. User software should ensure the
appropriate interrupt flag bits are clear
prior to enabling an interrupt.

INTCON: INTERRUPT CONTROL REGISTER

R/W-0/0

R-0/0

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF(1)

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

GIE: Global Interrupt Enable bit

1 = Enables all active interrupts
0 = Disables all interrupts

bit 6

PEIE: Peripheral Interrupt Enable bit

1 = Enables all active peripheral interrupts
0 = Disables all peripheral interrupts

bit 5

TMR0IE: Timer0 Overflow Interrupt Enable bit

1 = Enables the Timer0 interrupt
0 = Disables the Timer0 interrupt

bit 4

INTE: INT External Interrupt Enable bit

1 = Enables the INT external interrupt
0 = Disables the INT external interrupt

bit 3

IOCIE: Interrupt-on-Change Enable bit

1 = Enables the interrupt-on-change
0 = Disables the interrupt-on-change

bit 2

TMR0IF: Timer0 Overflow Interrupt Flag bit

1 = TMR0 register has overflowed
0 = TMR0 register did not overflow

bit 1

INTF: INT External Interrupt Flag bit

1 = The INT external interrupt occurred
0 = The INT external interrupt did not occur

bit 0

IOCIF: Interrupt-on-Change Interrupt Flag bit(1)

1 = When at least one of the interrupt-on-change pins changed state
0 = None of the interrupt-on-change pins have changed state

Note 1:

The IOCIF Flag bit is read-only and cleared when all the interrupt-on-change flags in the IOCBF register
have been cleared by software.

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PIC16(L)F1508/9
7.6.2

PIE1 REGISTER

The PIE1 register contains the interrupt enable bits, as

shown in Register 7-2.

Note:

Bit PEIE of the INTCON register must be

set to enable any peripheral interrupt.

PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1

R/W-0/0

U-0

R/W-0/0

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

TMR1GIE: Timer1 Gate Interrupt Enable bit

1 = Enables the Timer1 gate acquisition interrupt
0 = Disables the Timer1 gate acquisition interrupt

bit 6

ADIE: A/D Converter (ADC) Interrupt Enable bit

1 = Enables the ADC interrupt
0 = Disables the ADC interrupt

bit 5

RCIE: USART Receive Interrupt Enable bit

1 = Enables the USART receive interrupt
0 = Disables the USART receive interrupt

bit 4

TXIE: USART Transmit Interrupt Enable bit

1 = Enables the USART transmit interrupt
0 = Disables the USART transmit interrupt

bit 3

SSP1IE: Synchronous Serial Port (MSSP) Interrupt Enable bit

1 = Enables the MSSP interrupt
0 = Disables the MSSP interrupt

bit 2

Unimplemented: Read as 0

bit 1

TMR2IE: TMR2 to PR2 Match Interrupt Enable bit

1 = Enables the Timer2 to PR2 match interrupt
0 = Disables the Timer2 to PR2 match interrupt

bit 0

TMR1IE: Timer1 Overflow Interrupt Enable bit

1 = Enables the Timer1 overflow interrupt
0 = Disables the Timer1 overflow interrupt

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DS41609A-page 79

PIC16(L)F1508/9
7.6.3

PIE2 REGISTER

The PIE2 register contains the interrupt enable bits, as

shown in Register 7-3.

Note:

Bit PEIE of the INTCON register must be

set to enable any peripheral interrupt.

PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2

R/W-0/0

U-0

R/W-0/0

U-0

OSFIE

C2IE

C1IE

BCL1IE

NCO1IE

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

OSFIE: Oscillator Fail Interrupt Enable bit

1 = Enables the Oscillator Fail interrupt
0 = Disables the Oscillator Fail interrupt

bit 6

C2IE: Comparator C2 Interrupt Enable bit

1 = Enables the Comparator C2 interrupt
0 = Disables the Comparator C2 interrupt

bit 5

C1IE: Comparator C1 Interrupt Enable bit

1 = Enables the Comparator C1 interrupt
0 = Disables the Comparator C1 interrupt

bit 4

Unimplemented: Read as 0

bit 3

BCL1IE: MSSP Bus Collision Interrupt Enable bit

1 = Enables the MSSP Bus Collision Interrupt
0 = Disables the MSSP Bus Collision Interrupt

bit 2

NCO1IE: Numerically Controlled Oscillator Interrupt Enable bit

1 = Enables the NCO interrupt
0 = Disables the NCO interrupt

bit 1-0

Unimplemented: Read as 0

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PIC16(L)F1508/9
7.6.4

PIE3 REGISTER

The PIE3 register contains the interrupt enable bits, as

shown in Register 7-4.

Note:

Bit PEIE of the INTCON register must be

set to enable any peripheral interrupt.

PIE3: PERIPHERAL INTERRUPT ENABLE REGISTER 3

U-0

R/W-0/0

CLC4IE

CLC3IE

CLC2IE

CLC1IE

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

Unimplemented: Read as 0

bit 3

CLC4IE: Configurable Logic Block 4 Interrupt Enable bit

1 = Enables the CLC 4 interrupt
0 = Disables the CLC 4 interrupt

bit 2

CLC3IE: Configurable Logic Block 3 Interrupt Enable bit

1 = Enables the CLC 3 interrupt
0 = Disables the CLC 3 interrupt

bit 1

CLC2IE: Configurable Logic Block 2 Interrupt Enable bit

1 = Enables the CLC 2 interrupt
0 = Disables the CLC 2 interrupt

bit 0

CLC1IE: Configurable Logic Block 1 Interrupt Enable bit

1 = Enables the CLC 1 interrupt
0 = Disables the CLC 1 interrupt

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Preliminary

DS41609A-page 81

PIC16(L)F1508/9
7.6.5

PIR1 REGISTER

The PIR1 register contains the interrupt flag bits, as

shown in Register 7-5.

Note:

Interrupt flag bits are set when an interrupt

PIR1: PERIPHERAL INTERRUPT REQUEST REGISTER 1

R/W-0/0

U-0

R/W-0/0

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

TMR1GIF: Timer1 Gate Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 6

ADIF: A/D Converter Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 5

RCIF: USART Receive Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 4

TXIF: USART Transmit Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 3

SSP1IF: Synchronous Serial Port (MSSP) Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 2

Unimplemented: Read as 0

bit 1

TMR2IF: Timer2 to PR2 Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 0

TMR1IF: Timer1 Overflow Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

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PIC16(L)F1508/9
7.6.6

PIR2 REGISTER

The PIR2 register contains the interrupt flag bits, as

shown in Register 7-6.

Note:

Interrupt flag bits are set when an interrupt

PIR2: PERIPHERAL INTERRUPT REQUEST REGISTER 2

R/W-0/0

U-0

R/W-0/0

U-0

OSFIF

C2IF

C1IF

BCL1IF

NCO1IF

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

OSFIF: Oscillator Fail Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 6

C2IF: Numerically Controlled Oscillator Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 5

C1IF: Numerically Controlled Oscillator Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 4

Unimplemented: Read as 0

bit 3

BCL1IF: MSSP Bus Collision Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 2

NCO1IF: Numerically Controlled Oscillator Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 1-0

Unimplemented: Read as 0

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Preliminary

DS41609A-page 83

PIC16(L)F1508/9
7.6.7

PIR3 REGISTER

The PIR3 register contains the interrupt flag bits, as

shown in Register 7-7.

Note:

Interrupt flag bits are set when an interrupt

condition occurs, regardless of the state of
its corresponding enable bit or the Global
Enable bit, GIE, of the INTCON register.
User software should ensure the
appropriate interrupt flag bits are clear prior
to enabling an interrupt.

PIR3: PERIPHERAL INTERRUPT REQUEST REGISTER 3

U-0

R/W-0/0

CLC4IF

CLC3IF

CLC2IF

CLC1IF

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

Unimplemented: Read as 0

bit 3

CLC4IF: Configurable Logic Block 4 Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 2

CLC3IF: Configurable Logic Block 3 Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 1

CLC2IF: Configurable Logic Block 2 Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

bit 0

CLC1IF: Configurable Logic Block 1 Interrupt Flag bit

1 = Interrupt is pending
0 = Interrupt is not pending

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PIC16(L)F1508/9
TABLE 7-1:
Name
INTCON

SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPTS

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

OPTION_REG WPUEN

INTEDG TMR0CS TMR0SE

PIE1

TMR1GIE

ADIE

RCIE

TXIE

PSA

PS<2:0>

SSP1IE

TMR2IE

165
TMR1IE

PIE2

OSFIE

C2IE

C1IE

BCL1IE

NCO1IE

PIE3

CLC4IE

CLC2IE

CLC1IE

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

PIR2

OSFIF

C2IF

C1IF

BCL1IF

NCO1IF

PIR3

CLC4IF

CLC3IF

CLC2IF

CLC1IF

Legend: = unimplemented location, read as 0. Shaded cells are not used by interrupts.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 85

PIC16(L)F1508/9
NOTES:

DS41609A-page 86

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
8.0

POWER-DOWN MODE (SLEEP)

The Power-Down mode is entered by executing a

SLEEP instruction.
Upon entering Sleep mode, the following conditions exist:
1.
2.
3.
4.
5.

6.
7.

WDT will be cleared but keeps running, if

enabled for operation during Sleep.
PD bit of the STATUS register is cleared.
TO bit of the STATUS register is set.
CPU clock is disabled.
31 kHz LFINTOSC is unaffected and peripherals
that operate from it may continue operation in
Sleep.
ADC is unaffected, if the dedicated FRC clock is
selected.
I/O ports maintain the status they had before
SLEEP was executed (driving high, low or highimpedance).
Resets other than WDT are not affected by
Sleep mode.

Refer to individual chapters for more details on

peripheral operation during Sleep.
To minimize current consumption, the following
conditions should be considered:

I/O pins should not be floating

External circuitry sinking current from I/O pins
Internal circuitry sourcing current from I/O pins
Current draw from pins with internal weak pull-ups
Modules using 31 kHz LFINTOSC
CWG, NCO and CLC modules using HFINTOSC

I/O pins that are high-impedance inputs should be

pulled to VDD or VSS externally to avoid switching
currents caused by floating inputs.
Examples of internal circuitry that might be sourcing
current include the FVR module. See Section 13.0
Fixed Voltage Reference (FVR) for more
information on this module.

2011 Microchip Technology Inc.

8.1

Wake-up from Sleep

The device can wake-up from Sleep through one of the

following events:
1. External Reset input on MCLR pin, if enabled
2. BOR Reset, if enabled
3. POR Reset
4. Watchdog Timer, if enabled
5. Any external interrupt
6. Interrupts by peripherals capable of running during Sleep (see individual peripheral for more
information)
The first three events will cause a device Reset. The
last three events are considered a continuation of program execution. To determine whether a device Reset
or wake-up event occurred, refer to Section 6.11
Determining the Cause of a Reset.
When the SLEEP instruction is being executed, the next
instruction (PC + 1) is prefetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be enabled. Wake-up will
occur regardless of the state of the GIE bit. If the GIE
bit is disabled, the device continues execution at the
instruction after the SLEEP instruction. If the GIE bit is
enabled, the device executes the instruction after the
SLEEP instruction, the device will then call the Interrupt
Service Routine. In cases where the execution of the
instruction following SLEEP is not desirable, the user
should have a NOP after the SLEEP instruction.
The WDT is cleared when the device wakes up from
Sleep, regardless of the source of wake-up.

8.1.1

WAKE-UP USING INTERRUPTS

When global interrupts are disabled (GIE cleared) and

any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
If the interrupt occurs before the execution of a
SLEEP instruction
- SLEEP instruction will execute as a NOP.
- WDT and WDT prescaler will not be cleared
- TO bit of the STATUS register will not be set
- PD bit of the STATUS register will not be
cleared.
If the interrupt occurs during or after the execution of a SLEEP instruction
- SLEEP instruction will be completely executed
- Device will immediately wake-up from Sleep
- WDT and WDT prescaler will be cleared
- TO bit of the STATUS register will be set
- PD bit of the STATUS register will be cleared

Preliminary

DS41609A-page 87

PIC16(L)F1508/9
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.

FIGURE 8-1:

WAKE-UP FROM SLEEP THROUGH INTERRUPT

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

CLKIN(1)
T1OSC(3)

CLKOUT(2)

Interrupt Latency (4)

Interrupt flag
GIE bit
(INTCON reg.)

Processor in
Sleep

Instruction Flow
PC
Instruction
Fetched
Instruction
Executed
Note

1:
2:
3:
4:

PC
Inst(PC) = Sleep
Inst(PC - 1)

PC + 1

PC + 2

Inst(PC + 1)

Inst(PC + 2)

Sleep

Inst(PC + 1)

PC + 2

Forced NOP

0004h

0005h

Inst(0004h)

Inst(0005h)

Forced NOP

Inst(0004h)

External clock. High, Medium, Low mode assumed.

CLKOUT is shown here for timing reference.
T1OSC; See Section 29.0 Electrical Specifications.
GIE = 1 assumed. In this case after wake-up, the processor calls the ISR at 0004h. If GIE = 0, execution will continue in-line.

DS41609A-page 88

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
8.2

Low-Power Sleep Mode

8.2.2

The PIC16F1508/9 device contains an internal Low

Dropout (LDO) voltage regulator, which allows the
device I/O pins to operate at voltages up to 5.5V while
the internal device logic operates at a lower voltage.
The LDO and its associated reference circuitry must
remain active when the device is in Sleep mode. The
PIC16F1508/9 allows the user to optimize the
operating current in Sleep, depending on the
application requirements.
A Low-Power Sleep mode can be selected by setting
the VREGPM bit of the VREGCON register. With this
bit set, the LDO and reference circuitry are placed in a
low-power state when the device is in Sleep.

8.2.1

SLEEP CURRENT VS. WAKE-UP

TIME

In the default operating mode, the LDO and reference

circuitry remain in the normal configuration while in
Sleep. The device is able to exit Sleep mode quickly
since all circuits remain active. In Low-Power Sleep
mode, when waking up from Sleep, an extra delay time
is required for these circuits to return to the normal configuration and stabilize.
The Low-Power Sleep mode is beneficial for applications that stay in Sleep mode for long periods of time.
The Normal mode is beneficial for applications that
need to wake from Sleep quickly and frequently.

2011 Microchip Technology Inc.

PERIPHERAL USAGE IN SLEEP

Some peripherals that can operate in Sleep mode will

not operate properly with the Low-Power Sleep mode
selected. The LDO will remain in the Normal Power
mode when those peripherals are enabled. The LowPower Sleep mode is intended for use with these
peripherals:

Brown-Out Reset (BOR)

Watchdog Timer (WDT)
External interrupt pin/Interrupt-on-change pins
Timer1 (with external clock source)

The Complementary Waveform Generator (CWG), the

Numerically Controlled Oscillator (NCO) and the Configurable Logic Cell (CLC) modules can utilize the
HFINTOSC oscillator as either a clock source or as an
input source. Under certain conditions, when the
HFINTOSC is selected for use with the CWG, NCO or
CLC modules, the HFINTOSC will remain active
during Sleep. This will have a direct effect on the
Sleep mode current.
Please refer to sections 24.5 Operation During
Sleep, 25.7 Operation In Sleep and 26.10 Operation During Sleep for more information.
Note:

Preliminary

The PIC16LF1508/9 does not have a configurable Low-Power Sleep mode.

PIC16LF1508/9 is an unregulated device
and is always in the lowest power state
when in Sleep, with no wake-up time penalty. This device has a lower maximum
VDD and I/O voltage than the
PIC16F1508/9. See Section 29.0 Electrical Specifications for more information.

DS41609A-page 89

PIC16(L)F1508/9
VREGCON: VOLTAGE REGULATOR CONTROL REGISTER(1)

U-0

R/W-0/0

R/W-1/1

VREGPM

Reserved

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-2

Unimplemented: Read as 0

bit 1

VREGPM: Voltage Regulator Power Mode Selection bit

1 = Low-Power Sleep mode enabled in Sleep
Draws lowest current in Sleep, slower wake-up
0 = Normal Power mode enabled in Sleep
Draws higher current in Sleep, faster wake-up

bit 0

Reserved: Read as 1. Maintain this bit set.

Note 1:

PIC16F1508/9 only.

TABLE 8-1:

SUMMARY OF REGISTERS ASSOCIATED WITH POWER-DOWN MODE

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

INTCON

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

IOCAF

IOCAF5

IOCAF4

IOCAF3

IOCAF2

IOCAF1

IOCAF0

127

IOCAN

IOCAN5

IOCAN4

IOCAN3

IOCAN2

IOCAN1

IOCAN0

127

IOCAP

IOCAP5

IOCAP4

IOCAP3

IOCAP2

IOCAP1

IOCAP0

127

IOCBF

IOCBF7

IOCBF6

IOCBF5

IOCBF4

128

IOCBN

IOCBN7

IOCBN6

IOCBN5

IOCBN4

128

IOCBP

IOCBP7

IOCBP6

IOCBP5

IOCBP4

128

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

PIE2

OSFIE

C2IE

C1IE

BCL1IE

NCO1IE

PIE3

CLC4IE

CLC2IE

CLC1IE

TMR2IF

TMR1IF

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

PIR2

OSFIF

C2IF

C1IF

BCL1IF

NCO1IF

PIR3

CLC4IF

CLC3IF

CLC2IF

CLC1IF

STATUS

WDTCON

SWDTEN

WDTPS<4:0>

Legend: = unimplemented, read as 0. Shaded cells are not used in Power-Down mode.

DS41609A-page 90

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
9.0

WATCHDOG TIMER

The Watchdog Timer is a system timer that generates

a Reset if the firmware does not issue a CLRWDT
instruction within the time-out period. The Watchdog
Timer is typically used to recover the system from
unexpected events.
The WDT has the following features:
Independent clock source
Multiple operating modes
- WDT is always on
- WDT is off when in Sleep
- WDT is controlled by software
- WDT is always off
Configurable time-out period is from 1 ms to 256
seconds (typical)
Multiple Reset conditions
Operation during Sleep

FIGURE 9-1:

WATCHDOG TIMER BLOCK DIAGRAM

WDTE<1:0> = 01
SWDTEN
WDTE<1:0> = 11

LFINTOSC

23-bit Programmable
Prescaler WDT

WDT Time-out

WDTE<1:0> = 10
Sleep

2011 Microchip Technology Inc.

WDTPS<4:0>

Preliminary

DS41609A-page 91

PIC16(L)F1508/9
9.1

Independent Clock Source

9.3

Time-Out Period

The WDT derives its time base from the 31 kHz

LFINTOSC internal oscillator. Time intervals in this
chapter are based on a nominal interval of 1 ms. See
Section 29.0 Electrical Specifications for the
LFINTOSC tolerances.

The WDTPS bits of the WDTCON register set the

time-out period from 1 ms to 256 seconds (nominal).
After a Reset, the default time-out period is 2 seconds.

9.2

The WDT is cleared when any of the following conditions occur:

WDT Operating Modes

The Watchdog Timer module has four operating modes

controlled by the WDTE<1:0> bits in Configuration
Words. See Table 9-1.

9.4

Clearing the WDT

When the WDTE bits of Configuration Words are set to

11, the WDT is always on.

WDT protection is active during Sleep.

See Table 9-2 for more information.

9.2.2

9.5

9.2.1

WDT IS ALWAYS ON

WDT IS OFF IN SLEEP

When the WDTE bits of Configuration Words are set to

10, the WDT is on, except in Sleep.
WDT protection is not active during Sleep.

9.2.3

WDT CONTROLLED BY SOFTWARE

When the WDTE bits of Configuration Words are set to

01, the WDT is controlled by the SWDTEN bit of the
WDTCON register.
WDT protection is unchanged by Sleep. See Table 9-1
for more details.

TABLE 9-1:

WDT OPERATING MODES

WDTE<1:0>

SWDTEN

Device
Mode

WDT
Mode

Active

Awake

Active

Sleep

Disabled

TABLE 9-2:

X
X

Any Reset
CLRWDT instruction is executed
Device enters Sleep
Device wakes up from Sleep
Oscillator fail
WDT is disabled

Operation During Sleep

When the device enters Sleep, the WDT is cleared. If

the WDT is enabled during Sleep, the WDT resumes
counting.
When the device exits Sleep, the WDT is cleared
again. The WDT remains clear until the OST, if
enabled, completes. See Section 5.0 Oscillator
Module (With Fail-Safe Clock Monitor) for more
information on the OST.
When a WDT time-out occurs while the device is in
Sleep, no Reset is generated. Instead, the device
wakes up and resumes operation. The TO and PD bits
in the STATUS register are changed to indicate the
event. The RWDT bit in the PCON register can also be
used. See Section 3.0 Memory Organization for
more information.

Active
Disabled
Disabled

WDT CLEARING CONDITIONS

Conditions

WDT

WDTE<1:0> = 00
WDTE<1:0> = 01 and SWDTEN = 0
WDTE<1:0> = 10 and enter Sleep

Cleared

CLRWDT Command
Oscillator Fail Detected
Exit Sleep + System Clock = INTOSC, EXTCLK
Change INTOSC divider (IRCF bits)

DS41609A-page 92

Unaffected

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
9.6

Watchdog Control Register

WDTCON: WATCHDOG TIMER CONTROL REGISTER

U-0

R/W-0/0

R/W-1/1

R/W-0/0

R/W-1/1

WDTPS<4:0>

bit 7

R/W-0/0
SWDTEN
bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-1

WDTPS<4:0>: Watchdog Timer Period Select bits(1)

Bit Value = Prescale Rate
00000 = 1:32 (Interval 1 ms nominal)
00001 = 1:64 (Interval 2 ms nominal)
00010 = 1:128 (Interval 4 ms nominal)
00011 = 1:256 (Interval 8 ms nominal)
00100 = 1:512 (Interval 16 ms nominal)
00101 = 1:1024 (Interval 32 ms nominal)
00110 = 1:2048 (Interval 64 ms nominal)
00111 = 1:4096 (Interval 128 ms nominal)
01000 = 1:8192 (Interval 256 ms nominal)
01001 = 1:16384 (Interval 512 ms nominal)
01010 = 1:32768 (Interval 1s nominal)
01011 = 1:65536 (Interval 2s nominal) (Reset value)
01100 = 1:131072 (217) (Interval 4s nominal)
01101 = 1:262144 (218) (Interval 8s nominal)
01110 = 1:524288 (219) (Interval 16s nominal)
01111 = 1:1048576 (220) (Interval 32s nominal)
10000 = 1:2097152 (221) (Interval 64s nominal)
10001 = 1:4194304 (222) (Interval 128s nominal)
10010 = 1:8388608 (223) (Interval 256s nominal)
10011 = Reserved. Results in minimum interval (1:32)

11111 = Reserved. Results in minimum interval (1:32)

bit 0

Note 1:

SWDTEN: Software Enable/Disable for Watchdog Timer bit

If WDTE<1:0> = 00:
This bit is ignored.
If WDTE<1:0> = 01:
1 = WDT is turned on
0 = WDT is turned off
If WDTE<1:0> = 1x:
This bit is ignored.
Times are approximate. WDT time is based on 31 kHz LFINTOSC.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 93

PIC16(L)F1508/9
TABLE 9-3:

SUMMARY OF REGISTERS ASSOCIATED WITH WATCHDOG TIMER

Name

Bit 7

OSCCON

Bit 6

PCON

Bit 5

Bit 4

Bit 3

IRCF<3:0>
STKUNF

RWDT

STATUS

WDTCON

CONFIG1

Legend:

Bit 0

SCS<1:0>

RMCLR

POR

WDTPS<4:0>

BOR

SWDTEN

x = unknown, u = unchanged, = unimplemented locations read as 0. Shaded cells are not used by Watchdog Timer.

TABLE 9-4:
Name

Bit 1

STKOVF

Legend:

Bit 2

SUMMARY OF CONFIGURATION WORD WITH WATCHDOG TIMER

Bits

Bit -/7

Bit -/6

Bit 13/5

Bit 12/4

Bit 11/3

13:8

FCMEN

IESO

CLKOUTEN

7:0

MCLRE

PWRTE

WDTE<1:0>

Bit 10/2

Bit 9/1

BOREN<1:0>
FOSC<2:0>

Bit 8/0

= unimplemented location, read as 0. Shaded cells are not used by Watchdog Timer.

DS41609A-page 94

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
10.0

FLASH PROGRAM MEMORY

CONTROL

The Flash program memory is readable and writable

during normal operation over the full VDD range.
Program memory is indirectly addressed using Special
Function Registers (SFRs). The SFRs used to access
program memory are:

PMCON1
PMCON2
PMDATL
PMDATH
PMADRL
PMADRH

Control bits RD and WR initiate read and write,

respectively. These bits cannot be cleared, only set, in
software. They are cleared by hardware at completion
of the read or write operation. The inability to clear the
WR bit in software prevents the accidental, premature
termination of a write operation.
The WREN bit, when set, will allow a write operation to
occur. On power-up, the WREN bit is clear. The
WRERR bit is set when a write operation is interrupted
by a Reset during normal operation. In these situations,
following Reset, the user can check the WRERR bit
and execute the appropriate error handling routine.
The PMCON2 register is a write-only register. Attempting
to read the PMCON2 register will return all 0s.

When accessing the program memory, the

PMDATH:PMDATL register pair forms a 2-byte word
that holds the 14-bit data for read/write, and the
PMADRH:PMADRL register pair forms a 2-byte word
that holds the 15-bit address of the program memory
location being read.
The write time is controlled by an on-chip timer. The write/
erase voltages are generated by an on-chip charge
pump.
The Flash program memory can be protected in two
ways; by code protection (CP bit in Configuration Words)
and write protection (WRT<1:0> bits in Configuration
Words).
0)(1),

disables access, reading

Code protection (CP =
and writing, to the Flash program memory via external
device programmers. Code protection does not affect
the self-write and erase functionality. Code protection
can only be reset by a device programmer performing
a Bulk Erase to the device, clearing all Flash program
memory, Configuration bits and User IDs.

To enable writes to the program memory, a specific

pattern (the unlock sequence), must be written to the
PMCON2 register. The required unlock sequence
prevents inadvertent writes to the program memory
write latches and Flash program memory.

10.2

It is important to understand the Flash program memory

structure for erase and programming operations. Flash
program memory is arranged in rows. A row consists of
a fixed number of 14-bit program memory words. A row
is the minimum size that can be erased by user software.
After a row has been erased, the user can reprogram
all or a portion of this row. Data to be written into the
program memory row is written to 14-bit wide data write
latches. These write latches are not directly accessible
to the user, but may be loaded via sequential writes to
the PMDATH:PMDATL register pair.
Note:

Write protection prohibits self-write and erase to a

portion or all of the Flash program memory as defined
by the bits WRT<1:0>. Write protection does not affect
a device programmers ability to read, write or erase the
device.
Note 1: Code protection of the entire Flash
program memory array is enabled by
clearing the CP bit of Configuration Words.

10.1

PMADRL and PMADRH Registers

The PMADRH:PMADRL register pair can address up

to a maximum of 32K words of program memory. When
selecting a program address value, the MSB of the
address is written to the PMADRH register and the LSB
is written to the PMADRL register.

10.1.1

If the user wants to modify only a portion

of a previously programmed row, then the
contents of the entire row must be read
and saved in RAM prior to the erase.
Then, new data and retained data can be
written into the write latches to reprogram
the row of Flash program memory. However, any unprogrammed locations can be
written without first erasing the row. In this
case, it is not necessary to save and
rewrite the other previously programmed
locations.

See Table 10-1 for Erase Row size and the number of
write latches for Flash program memory.

TABLE 10-1:

FLASH MEMORY
ORGANIZATION BY DEVICE

Device

PMCON1 AND PMCON2

REGISTERS

PMCON1 is the control register for Flash program

memory accesses.

2011 Microchip Technology Inc.

Flash Program Memory Overview

PIC16(L)F1508
PIC16(L)F1509

Preliminary

Row Erase
(words)

Write
Latches
(words)

DS41609A-page 95

PIC16(L)F1508/9
FIGURE 10-1:
10.2.1

READING THE FLASH PROGRAM

MEMORY

FLASH PROGRAM
MEMORY READ
FLOWCHART

To read a program memory location, the user must:

1.
2.
3.

Write
the
desired
address
to
the
PMADRH:PMADRL register pair.
Clear the CFGS bit of the PMCON1 register.
Then, set control bit RD of the PMCON1 register.

Once the read control bit is set, the program memory

Flash controller will use the second instruction cycle to
read the data. This causes the second instruction
immediately following the BSF PMCON1,RD instruction
to be ignored. The data is available in the very next cycle,
in the PMDATH:PMDATL register pair; therefore, it can
be read as two bytes in the following instructions.
PMDATH:PMDATL register pair will hold this value until
another read or until it is written to by the user.
Note:

The two instructions following a program

memory read are required to be NOPs.
This prevents the user from executing a
two-cycle instruction on the next
instruction after the RD bit is set.

Start
Read Operation

Select
Program or Configuration Memory
(CFGS)

Select
Word Address
(PMADRH:PMADRL)

Initiate Read operation

(RD = 1)

Instruction Fetched ignored

NOP execution forced

Instruction Fetched ignored

NOP execution forced

Data read now in

PMDATH:PMDATL

End
Read Operation

DS41609A-page 96

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 10-2:

FLASH PROGRAM MEMORY READ CYCLE EXECUTION

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Flash ADDR

Flash Data

PC + 1

INSTR (PC)

INSTR(PC - 1)
executed here

PC
+3
PC+3

PMADRH,PMADRL

INSTR (PC + 1)

BSF PMCON1,RD
executed here

PMDATH,PMDATL

INSTR(PC + 1)
instruction ignored
Forced NOP
executed here

PC + 4

INSTR (PC + 3)

INSTR(PC + 2)
instruction ignored
Forced NOP
executed here

PC + 5

INSTR (PC + 4)

INSTR(PC + 3)
executed here

INSTR(PC + 4)
executed here

RD bit

PMDATH
PMDATL
Register

EXAMPLE 10-1:

FLASH PROGRAM MEMORY READ

* This code block will read 1 word of program

* memory at the memory address:
PROG_ADDR_HI : PROG_ADDR_LO
*
data will be returned in the variables;
*
PROG_DATA_HI, PROG_DATA_LO
BANKSEL
MOVLW
MOVWF
MOVLW
MOVWF

PMADRL
PROG_ADDR_LO
PMADRL
PROG_ADDR_HI
PMADRH

; Select Bank for PMCON registers

;
; Store LSB of address
;
; Store MSB of address

BCF
BSF
NOP
NOP

PMCON1,CFGS
PMCON1,RD

;
;
;
;

Do not select Configuration Space

Initiate read
Ignored (Figure 10-2)
Ignored (Figure 10-2)

MOVF
MOVWF
MOVF
MOVWF

PMDATL,W
PROG_DATA_LO
PMDATH,W
PROG_DATA_HI

;
;
;
;

Get LSB of word

Store in user location
Get MSB of word
Store in user location

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 97

PIC16(L)F1508/9
10.2.2

FLASH MEMORY UNLOCK

SEQUENCE

FIGURE 10-3:

The unlock sequence is a mechanism that protects the

Flash program memory from unintended self-write programming or erasing. The sequence must be executed
and completed without interruption to successfully
complete any of the following operations:
Row Erase
Load program memory write latches
Write of program memory write latches to program memory
Write of program memory write latches to User
IDs

FLASH PROGRAM
MEMORY UNLOCK
SEQUENCE FLOWCHART
Start
Unlock Sequence

Write 055h to
PMCON2

The unlock sequence consists of the following steps:

Write 0AAh to
PMCON2

1. Write 55h to PMCON2

Initiate
Write or Erase operation
(WR = 1)

2. Write AAh to PMCON2

3. Set the WR bit in PMCON1
4. NOP instruction
5. NOP instruction
Once the WR bit is set, the processor will always force
two NOP instructions. When an Erase Row or Program
Row operation is being performed, the processor will stall
internal operations (typical 2 ms), until the operation is
complete and then resume with the next instruction.
When the operation is loading the program memory write
latches, the processor will always force the two NOP
instructions and continue uninterrupted with the next
instruction.

Instruction Fetched ignored

NOP execution forced

Instruction Fetched ignored

NOP execution forced

End
Unlock Sequence

Since the unlock sequence must not be interrupted,

global interrupts should be disabled prior to the unlock
sequence and re-enabled after the unlock sequence is
completed.

DS41609A-page 98

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
10.2.3

ERASING FLASH PROGRAM

MEMORY

FIGURE 10-4:

While executing code, program memory can only be

erased by rows. To erase a row:
1.
2.
3.
4.
5.

Load the PMADRH:PMADRL register pair with

any address within the row to be erased.
Clear the CFGS bit of the PMCON1 register.
Set the FREE and WREN bits of the PMCON1
register.
Write 55h, then AAh, to PMCON2 (Flash
programming unlock sequence).
Set control bit WR of the PMCON1 register to
begin the erase operation.

See Example 10-2.

After the BSF PMCON1,WR instruction, the processor
requires two cycles to set up the erase operation. The
user must place two NOP instructions immediately following the WR bit set instruction. The processor will
halt internal operations for the typical 2 ms erase time.
This is not Sleep mode as the clocks and peripherals
will continue to run. After the erase cycle, the processor
will resume operation with the third instruction after the
PMCON1 write instruction.

FLASH PROGRAM
MEMORY ERASE
FLOWCHART
Start
Erase Operation

Disable Interrupts
(GIE = 0)

Select
Program or Configuration Memory
(CFGS)

Select Row Address

(PMADRH:PMADRL)

Select Erase Operation

(FREE = 1)

Enable Write/Erase Operation

(WREN = 1)

Unlock Sequence
Figure 10-3
(FIGURE
x-x)

CPU stalls while

Erase operation completes
(2ms typical)

Disable Write/Erase Operation

(WREN = 0)

Re-enable Interrupts
(GIE = 1)

End
Erase Operation

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 99

PIC16(L)F1508/9
EXAMPLE 10-2:

ERASING ONE ROW OF PROGRAM MEMORY

Required
Sequence

; This row erase routine assumes the following:

; 1. A valid address within the erase row is loaded in ADDRH:ADDRL
; 2. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F (common RAM)

BCF
BANKSEL
MOVF
MOVWF
MOVF
MOVWF
BCF
BSF
BSF

INTCON,GIE
PMADRL
ADDRL,W
PMADRL
ADDRH,W
PMADRH
PMCON1,CFGS
PMCON1,FREE
PMCON1,WREN

MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
NOP

55h
PMCON2
0AAh
PMCON2
PMCON1,WR

BCF
BSF

DS41609A-page 100

PMCON1,WREN
INTCON,GIE

; Disable ints so required sequences will execute properly

; Load lower 8 bits of erase address boundary
; Load upper 6 bits of erase address boundary
; Not configuration space
; Specify an erase operation
; Enable writes
;
;
;
;
;
;
;
;
;
;

Start of required sequence to initiate erase

Write 55h
Write AAh
Set WR bit to begin erase
NOP instructions are forced as processor starts
row erase of program memory.
The processor stalls until the erase process is complete
after erase processor continues with 3rd instruction

; Disable writes
; Enable interrupts

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
10.2.4

WRITING TO FLASH PROGRAM

MEMORY

Program memory is programmed using the following

steps:
1.
2.
3.
4.

Load the address in PMADRH:PMADRL of the

row to be programmed.
Load each write latch with data.
Initiate a programming operation.
Repeat steps 1 through 3 until all data is written.

The following steps should be completed to load the

write latches and program a row of program memory.
These steps are divided into two parts. First, each write
latch is loaded with data from the PMDATH:PMDATL
using the unlock sequence with LWLO = 1. When the
last word to be loaded into the write latch is ready, the
LWLO bit is cleared and the unlock sequence
executed. This initiates the programming operation,
writing all the latches into Flash program memory.
Note:

Before writing to program memory, the word(s) to be

written must be erased or previously unwritten. Program memory can only be erased one row at a time. No
automatic erase occurs upon the initiation of the write.
Program memory can be written one or more words at
a time. The maximum number of words written at one
time is equal to the number of write latches. See
Figure 10-5 (row writes to program memory with 32
write latches) for more details.
The write latches are aligned to the Flash row address
boundary defined by the upper 10-bits of
PMADRH:PMADRL, (PMADRH<6:0>:PMADRL<7:5>)
with the lower 5-bits of PMADRL, (PMADRL<4:0>)
determining the write latch being loaded. Write operations do not cross these boundaries. At the completion
of a program memory write operation, the data in the
write latches is reset to contain 0x3FFF.

The special unlock sequence is required

to load a write latch with data or initiate a
Flash programming operation. If the
unlock sequence is interrupted, writing to
the latches or program memory will not be
initiated.

1.
2.
3.

Set the WREN bit of the PMCON1 register.

Clear the CFGS bit of the PMCON1 register.
Set the LWLO bit of the PMCON1 register.
When the LWLO bit of the PMCON1 register is
1, the write sequence will only load the write
latches and will not initiate the write to Flash
program memory.
4. Load the PMADRH:PMADRL register pair with
the address of the location to be written.
5. Load the PMDATH:PMDATL register pair with
the program memory data to be written.
6. Execute the unlock sequence (Section 10.2.2
Flash Memory Unlock Sequence). The write
latch is now loaded.
7. Increment the PMADRH:PMADRL register pair
to point to the next location.
8. Repeat steps 5 through 7 until all but the last
write latch has been loaded.
9. Clear the LWLO bit of the PMCON1 register.
When the LWLO bit of the PMCON1 register is
0, the write sequence will initiate the write to
Flash program memory.
10. Load the PMDATH:PMDATL register pair with
the program memory data to be written.
11. Execute the unlock sequence (Section 10.2.2
Flash Memory Unlock Sequence). The
entire program memory latch content is now
written to Flash program memory.
Note:

The program memory write latches are

reset to the blank state (0x3FFF) at the
completion of every write or erase
operation. As a result, it is not necessary
to load all the program memory write
latches. Unloaded latches will remain in
the blank state.

An example of the complete write sequence is shown in

Example 10-3. The initial address is loaded into the
PMADRH:PMADRL register pair; the data is loaded
using indirect addressing.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 101

BLOCK WRITES TO FLASH PROGRAM MEMORY WITH 32 WRITE LATCHES

0 7

5 4

PMADRH
-

0
PMADRL

5
-

PMDATH
6

0
PMDATL
8

14
10

Program Memory Write Latches

14
Write Latch #0
00h

PMADRL<4:0>

Preliminary

CFGS = 0

2011 Microchip Technology Inc.

PMADRH<6:0>
:PMADRL<7:5>

Row
Address
Decode

Write Latch #1
01h

Write Latch #30 Write Latch #31

1Eh
1Fh

Row

Addr

000h

0000h

0001h

001Eh

001Fh

001h

0020h

0021h

003Eh

003Fh

002h

0040h

0041h

005Eh

005Fh

3FEh

7FC0h

7FC1h

7FDEh

7FDFh

3FFh

7FE0h

7FE1h

7FFEh

7FFFh

Flash Program Memory

400h

CFGS = 1

8000h - 8003h

8004h - 8005h

8006h

8007h - 8008h

8009h - 801Fh

USER ID 0 - 3

reserved

DEVICEID
REVID

Configuration
Words

reserved

Configuration Memory

PIC16(L)F1508/9

DS41609A-page 102

FIGURE 10-5:

PIC16(L)F1508/9
FIGURE 10-6:

FLASH PROGRAM MEMORY WRITE FLOWCHART

Start
Write Operation

Determine number of words

to be written into Program or
Configuration Memory.
The number of words cannot
exceed the number of words
per row.
(word_cnt)

Disable Interrupts
(GIE = 0)

Select
Program or Config. Memory
(CFGS)

Select Row Address

(PMADRH:PMADRL)

Enable Write/Erase
Operation (WREN = 1)

Load the value to write

(PMDATH:PMDATL)

Update the word counter

(word_cnt--)

Last word to
write ?

Yes

No
Unlock Sequence
(Figure10-3
x-x)
Figure

Select Write Operation

(FREE = 0)
No delay when writing to
Program Memory Latches
Load Write Latches Only
(LWLO = 1)

Increment Address
(PMADRH:PMADRL++)

Write Latches to Flash

(LWLO = 0)

Unlock Sequence
(Figure10-3
x-x)
Figure

CPU stalls while Write

operation completes
(2ms typical)

Disable
Write/Erase Operation
(WREN = 0)

Re-enable Interrupts
(GIE = 1)

End
Write Operation

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 103

PIC16(L)F1508/9
EXAMPLE 10-3:
;
;
;
;
;
;
;

WRITING TO FLASH PROGRAM MEMORY

This write routine assumes the following:

1. 64 bytes of data are loaded, starting at the address in DATA_ADDR
2. Each word of data to be written is made up of two adjacent bytes in DATA_ADDR,
stored in little endian format
3. A valid starting address (the least significant bits = 00000) is loaded in ADDRH:ADDRL
4. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F (common RAM)
BCF
BANKSEL
MOVF
MOVWF
MOVF
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
BCF
BSF
BSF

INTCON,GIE
PMADRH
ADDRH,W
PMADRH
ADDRL,W
PMADRL
LOW DATA_ADDR
FSR0L
HIGH DATA_ADDR
FSR0H
PMCON1,CFGS
PMCON1,WREN
PMCON1,LWLO

;
;
;
;
;
;
;
;
;
;
;
;
;

Disable ints so required sequences will execute properly

Bank 3
Load initial address

MOVIW
MOVWF
MOVIW
MOVWF

FSR0++
PMDATL
FSR0++
PMDATH

; Load first data byte into lower

;
; Load second data byte into upper
;

MOVF
XORLW
ANDLW
BTFSC
GOTO

PMADRL,W
0x1F
0x1F
STATUS,Z
START_WRITE

; Check if lower bits of address are '00000'

; Check if we're on the last of 32 addresses
;
; Exit if last of 32 words,
;

MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP

55h
PMCON2
0AAh
PMCON2
PMCON1,WR

;
;
;
;
;
;
;
;

PMADRL,F
LOOP

; Still loading latches Increment address

; Write next latches

PMCON1,LWLO

; No more loading latches - Actually start Flash program

; memory write

55h
PMCON2
0AAh
PMCON2
PMCON1,WR

;
;
;
;
;
;
;
;
;
;
;
;
;

Load initial data address

Load initial data address
Not configuration space
Enable writes
Only Load Write Latches

Required
Sequence

LOOP

NOP
INCF
GOTO

Required
Sequence

START_WRITE
BCF

MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
NOP

BCF
BSF

DS41609A-page 104

PMCON1,WREN
INTCON,GIE

Start of required write sequence:

Write 55h
Write AAh
Set WR bit to begin write
NOP instructions are forced as processor
loads program memory write latches

Start of required write sequence:

Write 55h
Write AAh
Set WR bit to begin write
NOP instructions are forced as processor writes
all the program memory write latches simultaneously
to program memory.
After NOPs, the processor
stalls until the self-write process in complete
after write processor continues with 3rd instruction
Disable writes
Enable interrupts

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
10.3

Modifying Flash Program Memory

FIGURE 10-7:

When modifying existing data in a program memory

row, and data within that row must be preserved, it must
first be read and saved in a RAM image. Program
memory is modified using the following steps:
1.
2.
3.
4.
5.
6.
7.

Load the starting address of the row to be

modified.
Read the existing data from the row into a RAM
image.
Modify the RAM image to contain the new data
to be written into program memory.
Load the starting address of the row to be
rewritten.
Erase the program memory row.
Load the write latches with data from the RAM
image.
Initiate a programming operation.

FLASH PROGRAM
MEMORY MODIFY
FLOWCHART

Start
Modify Operation

Read Operation
(Figure10-2
x.x)
Figure

An image of the entire row read

must be stored in RAM

Modify Image
The words to be modified are
changed in the RAM image

Erase Operation
(Figure10-4
x.x)
Figure

WRITE Operation
use RAM image
(Figure10-5
x.x)
Figure

End
Modify Operation

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 105

PIC16(L)F1508/9
10.4

User ID, Device ID and

Configuration Word Access

Instead of accessing program memory, the User IDs,

Device ID/Revision ID and Configuration Words can be
accessed when CFGS = 1 in the PMCON1 register.
This is the region that would be pointed to by
PC<15> = 1, but not all addresses are accessible.
Different access may exist for reads and writes. Refer
to Table 10-2.
When read access is initiated on an address outside
the
parameters
listed
in
Table 10-2,
the
PMDATH:PMDATL register pair is cleared, reading
back 0s.

TABLE 10-2:

USER ID, DEVICE ID AND CONFIGURATION WORD ACCESS (CFGS = 1)

Address

Function

Read Access

Write Access

8000h-8003h
8006h
8007h-8008h

User IDs
Device ID/Revision ID
Configuration Words 1 and 2

Yes
Yes
Yes

Yes
No
No

EXAMPLE 10-4:

CONFIGURATION WORD AND DEVICE ID ACCESS

* This code block will read 1 word of program memory at the memory address:
*
PROG_ADDR_LO (must be 00h-08h) data will be returned in the variables;
*
PROG_DATA_HI, PROG_DATA_LO
BANKSEL
MOVLW
MOVWF
CLRF

PMADRL
PROG_ADDR_LO
PMADRL
PMADRH

; Select correct Bank

;
; Store LSB of address
; Clear MSB of address

BSF
BCF
BSF
NOP
NOP
BSF

PMCON1,CFGS
INTCON,GIE
PMCON1,RD

INTCON,GIE

;
;
;
;
;
;

Select Configuration Space

Disable interrupts
Initiate read
Executed (See Figure 10-2)
Ignored (See Figure 10-2)
Restore interrupts

MOVF
MOVWF
MOVF
MOVWF

PMDATL,W
PROG_DATA_LO
PMDATH,W
PROG_DATA_HI

;
;
;
;

Get LSB of word

Store in user location
Get MSB of word
Store in user location

DS41609A-page 106

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
10.5

Write Verify

It is considered good programming practice to verify that

program memory writes agree with the intended value.
Since program memory is stored as a full page then the
stored program memory contents are compared with the
intended data stored in RAM after the last write is
complete.

FIGURE 10-8:

FLASH PROGRAM
MEMORY VERIFY
FLOWCHART
Start
Verify Operation

This routine assumes that the last row

of data written was from an image
saved in RAM. This image will be used
to verify the data currently stored in
Flash Program Memory.

Read Operation
(Figure
x.x)
Figure
10-2

PMDAT =
RAM image
?
Yes

Fail
Verify Operation

Last
Word ?
Yes
End
Verify Operation

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 107

PIC16(L)F1508/9
10.6

Flash Program Memory Control Registers

PMDATL: PROGRAM MEMORY DATA LOW BYTE REGISTER

R/W-x/u

PMDAT<7:0>
bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

PMDAT<7:0>: Read/write value for Least Significant bits of program memory

PMDATH: PROGRAM MEMORY DATA HIGH BYTE REGISTER

U-0

R/W-x/u

PMDAT<13:8>

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-0

PMDAT<13:8>: Read/write value for Most Significant bits of program memory

PMADRL: PROGRAM MEMORY ADDRESS LOW BYTE REGISTER

R/W-0/0

PMADR<7:0>
bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

PMADR<7:0>: Specifies the Least Significant bits for program memory address

PMADRH: PROGRAM MEMORY ADDRESS HIGH BYTE REGISTER

R/W-0/0

PMADR<14:8>

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

Unimplemented: Read as 1

bit 6-0

PMADR<14:8>: Specifies the Most Significant bits for program memory address

DS41609A-page 108

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 10-5:

PMCON1: PROGRAM MEMORY CONTROL 1 REGISTER

U-1(1)

R/W-0/0

R/W/HC-0/0

R/W/HC-x/q(2)

R/W-0/0

R/S/HC-0/0

CFGS

LWLO

FREE

WRERR

WREN

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

S = Bit can only be set

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

HC = Bit is cleared by hardware

bit 7

Unimplemented: Read as 1

bit 6

CFGS: Configuration Select bit

1 = Access Configuration, User ID and Device ID Registers
0 = Access Flash program memory

bit 5

LWLO: Load Write Latches Only bit(3)

1 = Only the addressed program memory write latch is loaded/updated on the next WR command
0 = The addressed program memory write latch is loaded/updated and a write of all program memory write latches
will be initiated on the next WR command

bit 4

FREE: Program Flash Erase Enable bit

1 = Performs an erase operation on the next WR command (hardware cleared upon completion)
0 = Performs a write operation on the next WR command

bit 3

WRERR: Program/Erase Error Flag bit

1 = Condition indicates an improper program or erase sequence attempt or termination (bit is set automatically
on any set attempt (write 1) of the WR bit).
0 = The program or erase operation completed normally.

bit 2

WREN: Program/Erase Enable bit

1 = Allows program/erase cycles
0 = Inhibits programming/erasing of program Flash

bit 1

WR: Write Control bit

1 = Initiates a program Flash program/erase operation.
The operation is self-timed and the bit is cleared by hardware once operation is complete.
The WR bit can only be set (not cleared) in software.
0 = Program/erase operation to the Flash is complete and inactive.

bit 0

RD: Read Control bit

1 = Initiates a program Flash read. Read takes one cycle. RD is cleared in hardware. The RD bit can only be set
(not cleared) in software.
0 = Does not initiate a program Flash read.

Note 1:
2:
3:

Unimplemented bit, read as 1.

The WRERR bit is automatically set by hardware when a program memory write or erase operation is started (WR = 1).
The LWLO bit is ignored during a program memory erase operation (FREE = 1).

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 109

PIC16(L)F1508/9
REGISTER 10-6:
W-0/0

PMCON2: PROGRAM MEMORY CONTROL 2 REGISTER

W-0/0

Program Memory Control Register 2

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

S = Bit can only be set

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

Flash Memory Unlock Pattern bits

To unlock writes, a 55h must be written first, followed by an AAh, before setting the WR bit of the
PMCON1 register. The value written to this register is used to unlock the writes. There are specific
timing requirements on these writes.

TABLE 10-3:

SUMMARY OF REGISTERS ASSOCIATED WITH FLASH PROGRAM MEMORY

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

INTCON

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

PMCON1

CFGS

LWLO

FREE

WRERR

WREN

109

PMCON2

Program Memory Control Register 2

110

PMADRL

PMADRL<7:0>

108

PMADRH

PMADRH<6:0>

PMDATL

PMDATH

Legend:

CONFIG1
CONFIG2
Legend:

108

PMDATH<5:0>

108

= unimplemented location, read as 0. Shaded cells are not used by Flash program memory module.

TABLE 10-4:
Name

108

PMDATL<7:0>

SUMMARY OF CONFIGURATION WORD WITH FLASH PROGRAM MEMORY

Bits

Bit -/7

Bit -/6

Bit 13/5

Bit 12/4

Bit 11/3

IESO

CLKOUTEN

Bit 10/2

13:8

FCMEN

7:0

MCLRE

PWRTE

13:8

LVP

DEBUG

LPBOR

BORV

7:0

Bit 9/1

Bit 8/0

BOREN<1:0>

WDTE<1:0>

FOSC<2:0>
STVREN
WRT<1:0>

44
45

= unimplemented location, read as 0. Shaded cells are not used by Flash program memory.

DS41609A-page 110

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
11.0

I/O PORTS

FIGURE 11-1:

GENERIC I/O PORT

OPERATION

Each port has three standard registers for its operation.

These registers are:
TRISx registers (data direction)
PORTx registers (reads the levels on the pins of
the device)
LATx registers (output latch)

Read LATx
D

Some ports may have one or more of the following

additional registers. These registers are:

Write LATx
Write PORTx

ANSELx (analog select)

WPUx (weak pull-up)

VDD

Data Register

In general, when a peripheral is enabled on a port pin,

that pin cannot be used as a general purpose output.
However, the pin can still be read.

Data Bus
I/O pin
Read PORTx
To peripherals
ANSELx

Device

PORTB

PORTC

PORT AVAILABILITY PER

DEVICE
PORTA

TABLE 11-1:

TRISx

PIC16(L)F1508/9

VSS

The Data Latch (LATx registers) is useful for

read-modify-write operations on the value that the I/O
pins are driving.
A write operation to the LATx register has the same
effect as a write to the corresponding PORTx register.
A read of the LATx register reads of the values held in
the I/O PORT latches, while a read of the PORTx
register reads the actual I/O pin value.
Ports that support analog inputs have an associated
ANSELx register. When an ANSEL bit is set, the digital
input buffer associated with that bit is disabled.
Disabling the input buffer prevents analog signal levels
on the pin between a logic high and low from causing
excessive current in the logic input circuitry. A
simplified model of a generic I/O port, without the
interfaces to other peripherals, is shown in Figure 11-1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 111

PIC16(L)F1508/9
11.1

Alternate Pin Function

The Alternate Pin Function Control register is used to

steer specific peripheral input and output functions
between different pins. The APFCON register is shown
in Register 11-1. For this device family, the following
functions can be moved between different pins.

SS
T1G
CLC1
NCO1

These bits have no effect on the values of any TRIS

APFCON: ALTERNATE PIN FUNCTION CONTROL REGISTER

U-0

R/W-0/0

U-0

R/W-0/0

SSSEL

T1GSEL

CLC1SEL

NCO1SEL

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-5

Unimplemented: Read as 0

bit 4

SSSEL: Pin Selection bit

1 = SS function is on RA3
0 = SS function is on RC6

bit 3

T1GSEL: Pin Selection bit

1 = T1G function is on RA3
0 = T1G function is on RA4

bit 2

Unimplemented: Read as 0

bit 1

CLC1SEL: Pin Selection bit

1 = CLC1 function is on RC5
0 = CLC1 function is on RA2

bit 0

NCO1SEL: Pin Selection bit

1 = NCO1 function is on RA6
0 = NCO1 function is on RC1

DS41609A-page 112

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
11.2

PORTA Registers

11.2.2

PORTA is a 6-bit wide, bidirectional port. The

corresponding data direction register is TRISA
(Register 11-3). Setting a TRISA bit (= 1) will make the
corresponding PORTA pin an input (i.e., disable the
output driver). Clearing a TRISA bit (= 0) will make the
corresponding PORTA pin an output (i.e., enables
output driver and puts the contents of the output latch
on the selected pin). The exception is RA3, which is
input only and its TRIS bit will always read as 1.
Example 11-1 shows how to initialize an I/O port.
Reading the PORTA register (Register 11-2) reads the
status of the pins, whereas writing to it will write to the
PORT latch. All write operations are read-modify-write
operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then
written to the PORT data latch (LATA).

Each PORTA pin is multiplexed with other functions. The

pins, their combined functions and their output priorities
are shown in Table 11-2.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the highest priority.
Analog input functions, such as ADC and comparator
inputs, are not shown in the priority lists. These inputs
are active when the I/O pin is set for Analog mode using
the ANSELx registers. Digital output functions may
control the pin when it is in Analog mode with the
priority shown below in Table 11-2.

TABLE 11-2:

Function Priority(1)

RA0

ICSPDAT
DACOUT1
RA0

RA1

RA2

DACOUT2
CLC1(2)
C1OUT
PWM3
RA2

RA3

None

RA4

CLKOUT
SOSCO
RA4

RA5

SOSCI
RA5

ANSELA REGISTER

The ANSELA register (Register 11-5) is used to

configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELA bit high will cause all
digital reads on the pin to be read as 0 and allow
analog functions on the pin to operate correctly.
The state of the ANSELA bits has no effect on digital
output functions. A pin with TRIS clear and ANSEL set
will still operate as a digital output, but the Input mode
will be analog. This can cause unexpected behavior
when executing read-modify-write instructions on the
affected port.
Note:

Note 1:
2:
3:

Priority listed from highest to lowest.

Default pin (see APFCON register).
Alternate pin (see APFCON register).

The ANSELA bits default to the Analog

mode after Reset. To use any pins as
digital general purpose or peripheral
inputs, the corresponding ANSEL bits
must be initialized to 0 by user software.

EXAMPLE 11-1:
BANKSEL
CLRF
BANKSEL
CLRF
BANKSEL
CLRF
BANKSEL
MOVLW
MOVWF

PORTA OUTPUT PRIORITY

Pin Name

The TRISA register (Register 11-3) controls the

PORTA pin output drivers, even when they are being
used as analog inputs. The user should ensure the bits
in the TRISA register are maintained set when using
them as analog inputs. I/O pins configured as analog
input always read 0.

11.2.1

PORTA FUNCTIONS AND OUTPUT

PRIORITIES

INITIALIZING PORTA

PORTA
PORTA
LATA
LATA
ANSELA
ANSELA
TRISA
B'00111000'
TRISA

;
;Init PORTA
;Data Latch
;
;
;digital I/O
;
;Set RA<5:3> as inputs
;and set RA<2:0> as
;outputs

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 113

PIC16(L)F1508/9
REGISTER 11-2:

PORTA: PORTA REGISTER

U-0

R/W-x/x

R-x/x

R/W-x/x

RA5

RA4

RA3

RA2

RA1

RA0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-0

RA<5:0>: PORTA I/O Value bits(1)

1 = Port pin is > VIH
0 = Port pin is < VIL

Note 1:

Writes to PORTA are actually written to corresponding LATA register. Reads from PORTA register is return
of actual I/O pin values.

TRISA: PORTA TRI-STATE REGISTER

U-0

R/W-1/1

U-1

R/W-1/1

TRISA5

TRISA4

(1)

TRISA2

TRISA1

TRISA0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-4

TRISA<5:4>: PORTA Tri-State Control bit

1 = PORTA pin configured as an input (tri-stated)
0 = PORTA pin configured as an output

bit 3

Unimplemented: Read as 1

bit 2-0

TRISA<2:0>: PORTA Tri-State Control bit

1 = PORTA pin configured as an input (tri-stated)
0 = PORTA pin configured as an output

Note 1:

Unimplemented, read as 1.

DS41609A-page 114

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 11-4:

LATA: PORTA DATA LATCH REGISTER

U-0

R/W-x/u

U-0

R/W-x/u

LATA5

LATA4

LATA2

LATA1

LATA0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-4

LATA<5:4>: RA<5:4> Output Latch Value bits(1)

bit 3

Unimplemented: Read as 0

bit 2-0

LATA<2:0>: RA<2:0> Output Latch Value bits(1)

Note 1:

Writes to PORTA are actually written to corresponding LATA register. Reads from PORTA register is return
of actual I/O pin values.

ANSELA: PORTA ANALOG SELECT REGISTER

U-0

R/W-1/1

U-0

R/W-1/1

ANSA4

ANSA2

ANSA1

ANSA0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-5

Unimplemented: Read as 0

bit 4

ANSA4: Analog Select between Analog or Digital Function on pins RA4, respectively
1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled.
0 = Digital I/O. Pin is assigned to port or digital special function.

bit 3

Unimplemented: Read as 0

bit 2-0

ANSA<2:0>: Analog Select between Analog or Digital Function on pins RA<2:0>, respectively
1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled.
0 = Digital I/O. Pin is assigned to port or digital special function.

Note 1:

When setting a pin to an analog input, the corresponding TRIS bit must be set to Input mode in order to
allow external control of the voltage on the pin.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 115

PIC16(L)F1508/9
REGISTER 11-6:

WPUA: WEAK PULL-UP PORTA REGISTER

U-0

R/W-1/1

WPUA5

WPUA4

WPUA3

WPUA2

WPUA1

WPUA0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-0

WPUA<5:0>: Weak Pull-up Register bits(3)

1 = Pull-up enabled
0 = Pull-up disabled

Note 1:
2:
3:

Global WPUEN bit of the OPTION_REG register must be cleared for individual pull-ups to be enabled.
The weak pull-up device is automatically disabled if the pin is configured as an output.
For the WPUA3 bit, when MCLRE = 1, weak pull-up is internally enabled, but not reported here.

TABLE 11-3:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH PORTA

Bit 7

Bit 6

Bit 5

Bit 4

ANSELA

APFCON

LATA

Bit 0

ANSA1

ANSA0

115

CLC1SEL

NCO1SEL

112

Bit 3

Bit 2

Bit 1

ANSA4

ANSA2

SSSEL

T1GSEL

LATA2

LATA1

LATA0

LATA5

LATA4

WPUEN

INTEDG

TMR0CS

TMR0SE

PSA

PORTA

RA5

RA4

RA3

RA2

RA1

RA0

114

TRISA

TRISA5

TRISA4

(1)

TRISA2

TRISA1

TRISA0

114

WPUA5

WPUA4

WPUA3

WPUA2

WPUA1

WPUA0

116

OPTION_REG

WPUA

Legend:
Note 1:

CONFIG1
Legend:

165

x = unknown, u = unchanged, = unimplemented locations read as 0. Shaded cells are not used by PORTA.
Unimplemented, read as 1.

TABLE 11-4:
Name

115

PS<2:0>

SUMMARY OF CONFIGURATION WORD WITH PORTA

Bits

Bit -/7

Bit -/6

Bit 13/5

Bit 12/4

Bit 11/3

IESO

CLKOUTEN

13:8

FCMEN

7:0

MCLRE

PWRTE

Bit 10/2

WDTE<1:0>

Bit 9/1

BOREN<1:0>
FOSC<2:0>

Bit 8/0

= unimplemented location, read as 0. Shaded cells are not used by PORTA.

DS41609A-page 116

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
11.3

PORTB Registers

11.3.2

PORTB is a 4-bit wide, bidirectional port. The

corresponding data direction register is TRISB
(Register 11-3). Setting a TRISB bit (= 1) will make the
corresponding PORTB pin an input (i.e., disable the
output driver). Clearing a TRISB bit (= 0) will make the
corresponding PORTB pin an output (i.e., enables
output driver and puts the contents of the output latch
on the selected pin). Example 11-1 shows how to
initialize an I/O port.
Reading the PORTB register (Register 11-2) reads the
status of the pins, whereas writing to it will write to the
PORT latch. All write operations are read-modify-write
operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then
written to the PORT data latch (LATB).

Each PORTB pin is multiplexed with other functions. The

TABLE 11-5:
Pin Name

The TRISB register (Register 11-3) controls the

PORTB pin output drivers, even when they are being
used as analog inputs. The user should ensure the bits
in the TRISB register are maintained set when using
them as analog inputs. I/O pins configured as analog
input always read 0.

11.3.1

ANSELB REGISTER

The ANSELB register (Register 11-5) is used to

configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELB bit high will cause all
digital reads on the pin to be read as 0 and allow
analog functions on the pin to operate correctly.

PORTB FUNCTIONS AND OUTPUT

PRIORITIES

Note 1:
2:
3:

PORTB OUTPUT PRIORITY

Function Priority(1)

RB4

SDA
RB4

RB5

RB6

SCL
SCK
RB6

RB7

CLC3
TX
RB7

Priority listed from highest to lowest.

Default pin (see APFCON register).
Alternate pin (see APFCON register).

The state of the ANSELB bits has no effect on digital

output functions. A pin with TRIS clear and ANSEL set
will still operate as a digital output, but the Input mode
will be analog. This can cause unexpected behavior
when executing read-modify-write instructions on the
affected port.
Note:

The ANSELB bits default to the Analog

mode after Reset. To use any pins as
digital general purpose or peripheral
inputs, the corresponding ANSEL bits
must be initialized to 0 by user software.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 117

PIC16(L)F1508/9
REGISTER 11-7:

PORTB: PORTB REGISTER

R/W-x/x

U-0

RB7

RB6

RB5

RB4

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

RB<7:4>: PORTB I/O Value bits(1)

1 = Port pin is > VIH
0 = Port pin is < VIL

bit 3-0

Unimplemented: Read as 0

Note 1:

Writes to PORTB are actually written to corresponding LATB register. Reads from PORTB register is
return of actual I/O pin values.

TRISB: PORTB TRI-STATE REGISTER

R/W-1/1

U-0

TRISB7

TRISB6

TRISB5

TRISB4

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

RB<7:4>: PORTB Tri-State Control bits

1 = PORTB pin configured as an input (tri-stated)
0 = PORTB pin configured as an output

bit 3-0

Unimplemented: Read as 0

DS41609A-page 118

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 11-9:

LATB: PORTB DATA LATCH REGISTER

R/W-x/u

U-0

LATB7

LATB6

LATB5

LATB4

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

LATB<7:4>: RB<7:4> Output Latch Value bits(1)

bit 3-0

Unimplemented: Read as 0

Note 1:

Writes to PORTB are actually written to corresponding LATB register. Reads from PORTB register is
return of actual I/O pin values.

REGISTER 11-10: ANSELB: PORTB ANALOG SELECT REGISTER

U-0

R/W-1/1

U-0

ANSB5

ANSB4

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-4

ANSB<5:4>: Analog Select between Analog or Digital Function on pins RB<5:4>, respectively
1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled.
0 = Digital I/O. Pin is assigned to port or digital special function.

bit 3-0

Unimplemented: Read as 0

Note 1:

When setting a pin to an analog input, the corresponding TRIS bit must be set to Input mode in order to
allow external control of the voltage on the pin.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 119

PIC16(L)F1508/9
REGISTER 11-11: WPUB: WEAK PULL-UP PORTB REGISTER
R/W-1/1

R/W-1/1

U-0

WPUB7

WPUB6

WPUB5

WPUB4

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

WPUB<7:4>: Weak Pull-up Register bits

1 = Pull-up enabled
0 = Pull-up disabled

bit 3-0

Unimplemented: Read as 0

Note 1:
2:

Global WPUEN bit of the OPTION_REG register must be cleared for individual pull-ups to be enabled.
The weak pull-up device is automatically disabled if the pin is configured as an output.

TABLE 11-6:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH PORTB

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ANSB5

ANSB4

119

ANSELB
APFCON
LATB
OPTION_REG
PORTB

SSSEL

T1GSEL

CLC1SEL

NCO1SEL

112

LATB7

LATB6

LATB5

LATB4

119

WPUEN

INTEDG

TMR0CS

TMR0SE

PSA

RB7

RB6

RB5

RB4

PS<2:0>

165
118

TRISB

TRISB7

TRISB6

TRISB5

TRISB4

118

WPUB

WPUB7

WPUB6

WPUB5

WPUB4

120

Legend:
Note 1:

x = unknown, u = unchanged, = unimplemented locations read as 0. Shaded cells are not used by PORTB.
Unimplemented, read as 1.

TABLE 11-7:
Name

CONFIG1
Legend:

SUMMARY OF CONFIGURATION WORD WITH PORTB

Bits

Bit -/7

Bit -/6

Bit 13/5

Bit 12/4

Bit 11/3

IESO

CLKOUTEN

13:8

FCMEN

7:0

MCLRE

PWRTE

Bit 10/2

WDTE<1:0>

Bit 9/1

BOREN<1:0>
FOSC<2:0>

Bit 8/0

= unimplemented location, read as 0. Shaded cells are not used by PORTB.

DS41609A-page 120

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
11.4

PORTC Registers

11.4.2

PORTC is a 8-bit wide, bidirectional port. The

corresponding data direction register is TRISC
(Register 11-13). Setting a TRISC bit (= 1) will make
the corresponding PORTC pin an input (i.e., put the
corresponding output driver in a High-Impedance
mode). Clearing a TRISC bit (= 0) will make the
corresponding PORTC pin an output (i.e., enable the
output driver and put the contents of the output latch
on the selected pin). Example 11-1 shows how to
initialize an I/O port.
Reading the PORTC register (Register 11-12) reads the
status of the pins, whereas writing to it will write to the
PORT latch. All write operations are read-modify-write
operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then written
to the PORT data latch (LATC).

Each PORTC pin is multiplexed with other functions. The

pins, their combined functions and their output priorities
are shown in Table 11-8.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the highest priority.
Analog input and some digital input functions are not
included in the output priority list. These input functions
can remain active when the pin is configured as an
output. Certain digital input functions override other
port functions and are included in the output priority list.

TABLE 11-8:
Pin Name

The TRISC register (Register 11-13) controls the

PORTC pin output drivers, even when they are being
used as analog inputs. The user should ensure the bits in
the TRISC register are maintained set when using them
as analog inputs. I/O pins configured as analog input
always read 0.

11.4.1

ANSELC REGISTER

The ANSELC register (Register 11-15) is used to

configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELC bit high will cause all
digital reads on the pin to be read as 0 and allow
analog functions on the pin to operate correctly.
The state of the ANSELC bits has no effect on digital output functions. A pin with TRIS clear and ANSELC set will
still operate as a digital output, but the Input mode will be
analog. This can cause unexpected behavior when executing read-modify-write instructions on the affected
port.
Note:

The ANSELC bits default to the Analog

mode after Reset. To use any pins as
digital general purpose or peripheral
inputs, the corresponding ANSEL bits
must be initialized to 0 by user software.

2011 Microchip Technology Inc.

PORTC FUNCTIONS AND OUTPUT

PRIORITIES

Function Priority(1)

RC0

CLC2
RC0

RC1

NCO1(2)
PWM4
RC1

RC2

RC3

PWM2
RC3

RC4

CWG1B
CLC4
C2OUT
RC4

RC5

CWG1A
CLC1(3)
PWM1
RC5

RC6

NCO1(3)
RC6

RC7

SDO
RC7

Note 1:
2:
3:

Preliminary

PORTC OUTPUT PRIORITY

Priority listed from highest to lowest.

Default pin (see APFCON register).
Alternate pin (see APFCON register).

DS41609A-page 121

PIC16(L)F1508/9
REGISTER 11-12: PORTC: PORTC REGISTER
R/W-x/u

R/W-x/u

RC7

RC6

RC5

RC4

RC3

RC2

RC1

RC0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

RC<7:0>: PORTC General Purpose I/O Pin bits

1 = Port pin is > VIH
0 = Port pin is < VIL

REGISTER 11-13: TRISC: PORTC TRI-STATE REGISTER

R/W-1/1

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

TRISC<7:0>: PORTC Tri-State Control bits

1 = PORTC pin configured as an input (tri-stated)
0 = PORTC pin configured as an output

REGISTER 11-14: LATC: PORTC DATA LATCH REGISTER

R/W-x/u

LATC7

LATC6

LATC5

LATC4

LATC3

LATC2

LATC1

LATC0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0
Note 1:

LATC<7:0>: PORTC Output Latch Value bits(1)

Writes to PORTC are actually written to corresponding LATC register. Reads from PORTC register is
return of actual I/O pin values.

DS41609A-page 122

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 11-15: ANSELC: PORTC ANALOG SELECT REGISTER
R/W-1/1

R/W-1/1

U-0

R/W-1/1

ANSC7

ANSC6

ANSC3

ANSC2

ANSC1

ANSC0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

ANSC<7:6>: Analog Select between Analog or Digital Function on pins RC<7:6>, respectively
1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled.
0 = Digital I/O. Pin is assigned to port or digital special function.

bit 5-4

Unimplemented: Read as 0

bit 3-0

ANSC<3:0>: Analog Select between Analog or Digital Function on pins RC<3:0>, respectively
1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled.
0 = Digital I/O. Pin is assigned to port or digital special function.

Note 1:

When setting a pin to an analog input, the corresponding TRIS bit must be set to Input mode in order to
allow external control of the voltage on the pin.

TABLE 11-9:

SUMMARY OF REGISTERS ASSOCIATED WITH PORTC

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ANSELC

ANSC7

ANSC6

ANSC3

ANSC2

ANSC1

ANSC0

123

LATC

LATC7

LATC6

LATC5

LATC4

LATC3

LATC2

LATC1

LATC0

122

RC7

RC6

RC5

RC4

RC3

RC2

RC1

RC0

122

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

Name

PORTC
TRISC
Legend:

x = unknown, u = unchanged, - = unimplemented locations read as 0. Shaded cells are not used by PORTC.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 123

PIC16(L)F1508/9
NOTES:

DS41609A-page 124

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
12.0

INTERRUPT-ON-CHANGE

12.3

The PORTA and PORTB pins can be configured to

operate as Interrupt-On-Change (IOC) pins. An interrupt
can be generated by detecting a signal that has either a
rising edge or a falling edge. Any individual port pin, or
combination of port pins, can be configured to generate
an interrupt. The interrupt-on-change module has the
following features:

Interrupt-on-Change enable (Master Switch)

Individual pin configuration
Rising and falling edge detection
Individual pin interrupt flags

The IOCAFx and IOCBFx bits located in the IOCAF and

IOCBF registers, respectively, are status flags that
correspond to the interrupt-on-change pins of the
associated port. If an expected edge is detected on an
appropriately enabled pin, then the status flag for that pin
will be set, and an interrupt will be generated if the IOCIE
bit is set. The IOCIF bit of the INTCON register reflects
the status of all IOCAFx and IOCBFx bits.

12.4

Clearing Interrupt Flags

The individual status flags, (IOCAFx and IOCBFx bits),

can be cleared by resetting them to zero. If another edge
is detected during this clearing operation, the associated
status flag will be set at the end of the sequence,
regardless of the value actually being written.

Figure 12-1 is a block diagram of the IOC module.

12.1

Interrupt Flags

Enabling the Module

To allow individual port pins to generate an interrupt, the

IOCIE bit of the INTCON register must be set. If the
IOCIE bit is disabled, the edge detection on the pin will
still occur, but an interrupt will not be generated.

In order to ensure that no detected edge is lost while

clearing flags, only AND operations masking out known
changed bits should be performed. The following
sequence is an example of what should be performed.

12.2

Individual Pin Configuration

EXAMPLE 12-1:

For each port pin, a rising edge detector and a falling

edge detector are present. To enable a pin to detect a
rising edge, the associated bit of the IOCxP register is
set. To enable a pin to detect a falling edge, the
associated bit of the IOCxN register is set.

MOVLW
XORWF
ANDWF

A pin can be configured to detect rising and falling

edges simultaneously by setting both associated bits of
the IOCxP and IOCxN registers, respectively.

12.5

CLEARING INTERRUPT
FLAGS
(PORTA EXAMPLE)

0xff
IOCAF, W
IOCAF, F

Operation in Sleep

The interrupt-on-change interrupt sequence will wake

the device from Sleep mode, if the IOCIE bit is set.
If an edge is detected while in Sleep mode, the IOCxF
register will be updated prior to the first instruction
executed out of Sleep.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 125

PIC16(L)F1508/9
FIGURE 12-1:

INTERRUPT-ON-CHANGE BLOCK DIAGRAM (PORTA EXAMPLE)

IOCANx

Q4Q1

Edge
Detect

RAx

IOCAPx

Data Bus =
0 or 1

Write IOCAFx

To Data Bus
IOCAFx

CK
IOCIE

R
Q2
From all other
IOCAFx individual
Pin Detectors

Q1
Q2
Q3
Q4
Q4Q1

DS41609A-page 126

Q2
Q3
Q4
Q4Q1

IOC interrupt
to CPU core

Q3
Q4

Q4
Q4Q1

Preliminary

Q4Q1

2011 Microchip Technology Inc.

PIC16(L)F1508/9
12.6

Interrupt-On-Change Registers

IOCAP: INTERRUPT-ON-CHANGE PORTA POSITIVE EDGE REGISTER

U-0

R/W-0/0

IOCAP5

IOCAP4

IOCAP3

IOCAP2

IOCAP1

IOCAP0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-0

IOCAP<5:0>: Interrupt-on-Change PORTA Positive Edge Enable bits

1 = Interrupt-on-Change enabled on the pin for a positive going edge. IOCAFx bit and IOCIF flag will be set
upon detecting an edge.
0 = Interrupt-on-Change disabled for the associated pin.

IOCAN: INTERRUPT-ON-CHANGE PORTA NEGATIVE EDGE REGISTER

U-0

R/W-0/0

IOCAN5

IOCAN4

IOCAN3

IOCAN2

IOCAN1

IOCAN0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

Unimplemented: Read as 0

bit 5-0

IOCAN<5:0>: Interrupt-on-Change PORTA Negative Edge Enable bits

1 = Interrupt-on-Change enabled on the pin for a negative going edge. IOCAFx bit and IOCIF flag will be set
upon detecting an edge.
0 = Interrupt-on-Change disabled for the associated pin.

IOCAF: INTERRUPT-ON-CHANGE PORTA FLAG REGISTER

U-0

R/W/HS-0/0

IOCAF5

IOCAF4

IOCAF3

IOCAF2

IOCAF1

IOCAF0

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

HS - Bit is set in hardware

bit 7-6

Unimplemented: Read as 0

bit 5-0

IOCAF<5:0>: Interrupt-on-Change PORTA Flag bits

1 = An enabled change was detected on the associated pin.
Set when IOCAPx = 1 and a rising edge was detected on RAx, or when IOCANx = 1 and a falling edge was
detected on RAx.
0 = No change was detected, or the user cleared the detected change.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 127

PIC16(L)F1508/9
REGISTER 12-4:

IOCBP: INTERRUPT-ON-CHANGE PORTB POSITIVE EDGE REGISTER

R/W-0/0

U-0

IOCBP7

IOCBP6

IOCBP5

IOCBP4

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

IOCBP<7:4>: Interrupt-on-Change PORTB Positive Edge Enable bits

1 = Interrupt-on-Change enabled on the pin for a positive going edge. IOCBFx bit and IOCIF flag will be set
upon detecting an edge.
0 = Interrupt-on-Change disabled for the associated pin.

bit 3-0

Unimplemented: Read as 0

IOCBN: INTERRUPT-ON-CHANGE PORTB NEGATIVE EDGE REGISTER

R/W-0/0

U-0

IOCBN7

IOCBN6

IOCBN5

IOCBN4

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

IOCBN<7:4>: Interrupt-on-Change PORTB Negative Edge Enable bits

1 = Interrupt-on-Change enabled on the pin for a negative going edge. IOCBFx bit and IOCIF flag will be set
upon detecting an edge.
0 = Interrupt-on-Change disabled for the associated pin.

bit 3-0

Unimplemented: Read as 0

IOCBF: INTERRUPT-ON-CHANGE PORTB FLAG REGISTER

R/W/HS-0/0

U-0

IOCBF7

IOCBF6

IOCBF5

IOCBF4

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

HS - Bit is set in hardware

bit 7-4

IOCBF<7:4>: Interrupt-on-Change PORTB Flag bits

1 = An enabled change was detected on the associated pin.
Set when IOCBPx = 1 and a rising edge was detected on RBx, or when IOCBNx = 1 and a falling edge was
detected on RBx.
0 = No change was detected, or the user cleared the detected change.

bit 3-0

Unimplemented: Read as 0

DS41609A-page 128

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 12-1:

SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPT-ON-CHANGE

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ANSELA

ANSA4

ANSA2

ANSA1

ANSA0

115

INTCON

Name

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

IOCAF

IOCAF5

IOCAF4

IOCAF3

IOCAF2

IOCAF1

IOCAF0

127

IOCAN

IOCAN5

IOCAN4

IOCAN3

IOCAN2

IOCAN1

IOCAN0

127

IOCAP

IOCAP5

IOCAP4

IOCAP3

IOCAP2

IOCAP1

IOCAP0

127

IOCBF

IOCBF7

IOCBF6

IOCBF5

IOCBF4

128

IOCBN

IOCBN7

IOCBN6

IOCBN5

IOCBN4

128

IOCBP

IOCBP7

IOCBP6

IOCBP5

IOCBP4

128

TRISA

TRISA5

TRISA4

(1)

TRISA2

TRISA1

TRISA0

114

TRISB7

TRISB6

TRISB5

TRISB4

118

TRISB

Legend:
Note 1:

= unimplemented location, read as 0. Shaded cells are not used by interrupt-on-change.

Unimplemented, read as 1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 129

PIC16(L)F1508/9
NOTES:

DS41609A-page 130

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
13.0

FIXED VOLTAGE REFERENCE

(FVR)

The Fixed Voltage Reference, or FVR, is a stable

voltage reference, independent of VDD, with 1.024V,
2.048V or 4.096V selectable output levels. The output
of the FVR can be configured to supply a reference
voltage to the following:
ADC input channel
Comparator positive input
Comparator negative input
The FVR can be enabled by setting the FVREN bit of
the FVRCON register.

13.1

Independent Gain Amplifier

The output of the FVR supplied to the ADC and

Comparators is routed through a programmable gain
amplifier. Each amplifier can be programmed for a gain
of 1x, 2x or 4x, to produce the three possible voltage
levels.

FIGURE 13-1:

The ADFVR<1:0> bits of the FVRCON register are

used to enable and configure the gain amplifier settings
for the reference supplied to the ADC module. Reference Section 15.0 Analog-to-Digital Converter
(ADC) Module for additional information.
The CDAFVR<1:0> bits of the FVRCON register are
used to enable and configure the gain amplifier settings
for the reference supplied to the comparator modules.
Reference Section 17.0 Comparator Module for
additional information.

13.2

FVR Stabilization Period

When the Fixed Voltage Reference module is enabled, it

requires time for the reference and amplifier circuits to
stabilize. Once the circuits stabilize and are ready for use,
the FVRRDY bit of the FVRCON register will be set. See
Section 29.0 Electrical Specifications for the
minimum delay requirement.

VOLTAGE REFERENCE BLOCK DIAGRAM

ADFVR<1:0>

CDAFVR<1:0>

2
X1
X2
X4

FVR BUFFER1
(To ADC Module)

X1
X2
X4

FVR BUFFER2
(To Comparators)

FVREN

+
FVRRDY

Any peripheral requiring the

Fixed Reference
(See Table 13-1)

TABLE 13-1:
Peripheral

PERIPHERALS REQUIRING THE FIXED VOLTAGE REFERENCE (FVR)

Conditions

Description

HFINTOSC

FOSC<2:0> = 010 and

IRCF<3:0> = 000x
BOREN<1:0> = 11

BOR always enabled.

BOR

BOREN<1:0> = 10 and BORFS = 1

BOR disabled in Sleep mode, BOR Fast Start enabled.

BOREN<1:0> = 01 and BORFS = 1

BOR under software control, BOR Fast Start enabled.

LDO

All PIC16F1508/9 devices, when

VREGPM = 1 and not in Sleep

The device runs off of the Low-Power Regulator when in

Sleep mode.

2011 Microchip Technology Inc.

INTOSC is active and device is not in Sleep.

Preliminary

DS41609A-page 131

PIC16(L)F1508/9
13.3

FVR Control Registers

FVRCON: FIXED VOLTAGE REFERENCE CONTROL REGISTER

R/W-0/0

R-q/q

R/W-0/0

FVREN

FVRRDY(1)

TSEN

TSRNG

R/W-0/0

CDAFVR<1:0>

R/W-0/0

ADFVR<1:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7

FVREN: Fixed Voltage Reference Enable bit

1 = Fixed Voltage Reference is enabled
0 = Fixed Voltage Reference is disabled

bit 6

FVRRDY: Fixed Voltage Reference Ready Flag bit(1)

1 = Fixed Voltage Reference output is ready for use
0 = Fixed Voltage Reference output is not ready or not enabled

bit 5

TSEN: Temperature Indicator Enable bit(3)

1 = Temperature Indicator is enabled
0 = Temperature Indicator is disabled

bit 4

TSRNG: Temperature Indicator Range Selection bit(3)

1 = VOUT = VDD - 4VT (High Range)
0 = VOUT = VDD - 2VT (Low Range)

bit 3-2

CDAFVR<1:0>: Comparator Fixed Voltage Reference Selection bits

11 = Comparator Fixed Voltage Reference Peripheral output is 4x (4.096V)(2)
10 = Comparator Fixed Voltage Reference Peripheral output is 2x (2.048V)(2)
01 = Comparator Fixed Voltage Reference Peripheral output is 1x (1.024V)
00 = Comparator Fixed Voltage Reference Peripheral output is off

bit 1-0

ADFVR<1:0>: ADC Fixed Voltage Reference Selection bit

11 = ADC Fixed Voltage Reference Peripheral output is 4x (4.096V)(2)
10 = ADC Fixed Voltage Reference Peripheral output is 2x (2.048V)(2)
01 = ADC Fixed Voltage Reference Peripheral output is 1x (1.024V)
00 = ADC Fixed Voltage Reference Peripheral output is off

Note 1:
2:
3:

FVRRDY is always 1 for the PIC16F1508/9 devices.

Fixed Voltage Reference output cannot exceed VDD.
See Section 14.0 Temperature Indicator Module for additional information.

TABLE 13-2:
Name
FVRCON

Legend:

SUMMARY OF REGISTERS ASSOCIATED WITH THE FIXED VOLTAGE REFERENCE

Bit 7

Bit 6

Bit 5

Bit 4

FVREN

FVRRDY

TSEN

TSRNG

Bit 3

Bit 2

CDAFVR>1:0>

Bit 1

Bit 0

ADFVR<1:0>

Shaded cells are unused by the Fixed Voltage Reference module.

DS41609A-page 132

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
14.0

TEMPERATURE INDICATOR
MODULE

FIGURE 14-1:

This family of devices is equipped with a temperature

circuit designed to measure the operating temperature
of the silicon die. The circuits range of operating
temperature falls between -40C and +85C. The
output is a voltage that is proportional to the device
temperature. The output of the temperature indicator is
internally connected to the device ADC.

TEMPERATURE CIRCUIT
DIAGRAM
VDD
TSEN

TSRNG

The circuit may be used as a temperature threshold

detector or a more accurate temperature indicator,
depending on the level of calibration performed. A onepoint calibration allows the circuit to indicate a
temperature closely surrounding that point. A two-point
calibration allows the circuit to sense the entire range
of temperature more accurately. Reference Application
Note AN1333, Use and Calibration of the Internal
Temperature Indicator (DS01333) for more details
regarding the calibration process.

14.1

Circuit Operation

14.2

Figure 14-1 shows a simplified block diagram of the

temperature circuit. The proportional voltage output is
achieved by measuring the forward voltage drop across
multiple silicon junctions.
Equation 14-1 describes the output characteristics of
the temperature indicator.

EQUATION 14-1:

VOUT

VOUT RANGES

To ADC

Minimum Operating VDD

When the temperature circuit is operated in low range,

the device may be operated at any operating voltage
that is within specifications.
When the temperature circuit is operated in high range,
the device operating voltage, VDD, must be high
enough to ensure that the temperature circuit is correctly biased.
Table 14-1 shows the recommended minimum VDD vs.
range setting.

High Range: VOUT = VDD - 4VT

TABLE 14-1:
Low Range: VOUT = VDD - 2VT

The temperature sense circuit is integrated with the

Fixed Voltage Reference (FVR) module. See
Section 13.0 Fixed Voltage Reference (FVR) for
more information.
The circuit is enabled by setting the TSEN bit of the
FVRCON register. When disabled, the circuit draws no
current.
The circuit operates in either high or low range. The high
range, selected by setting the TSRNG bit of the
FVRCON register, provides a wider output voltage. This
provides more resolution over the temperature range,
but may be less consistent from part to part. This range
requires a higher bias voltage to operate and thus, a
higher VDD is needed.
The low range is selected by clearing the TSRNG bit of
the FVRCON register. The low range generates a lower
voltage drop and thus, a lower bias voltage is needed to
operate the circuit. The low range is provided for low
voltage operation.

2011 Microchip Technology Inc.

RECOMMENDED VDD VS.

RANGE

Min. VDD, TSRNG = 1

Min. VDD, TSRNG = 0

3.6V

1.8V

14.3

Temperature Output

The output of the circuit is measured using the internal

Analog-to-Digital Converter. A channel is reserved for
the temperature circuit output. Refer to Section 15.0
Analog-to-Digital Converter (ADC) Module for
detailed information.

14.4

ADC Acquisition Time

To ensure accurate temperature measurements, the

user must wait at least 200 s after the ADC input
multiplexer is connected to the temperature indicator
output before the conversion is performed. In addition,
the user must wait 200 s between sequential
conversions of the temperature indicator output.

Preliminary

DS41609A-page 133

PIC16(L)F1508/9
TABLE 14-2:
Name
FVRCON

Legend:

SUMMARY OF REGISTERS ASSOCIATED WITH THE TEMPERATURE INDICATOR

Bit 7

Bit 6

Bit 5

Bit 4

FVREN

FVRRDY

TSEN

TSRNG

Bit 3

Bit 2

CDAFVR<1:0>

Bit 1

Bit 0

ADFVR<1:0>

Shaded cells are unused by the temperature indicator module.

DS41609A-page 134

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
15.0

ANALOG-TO-DIGITAL
CONVERTER (ADC) MODULE

The ADC can generate an interrupt upon completion of

a conversion. This interrupt can be used to wake-up the
device from Sleep.

The Analog-to-Digital Converter (ADC) allows

conversion of an analog input signal to a 10-bit binary
representation of that signal. This device uses analog
inputs, which are multiplexed into a single sample and
hold circuit. The output of the sample and hold is
connected to the input of the converter. The converter
generates a 10-bit binary result via successive
approximation and stores the conversion result into the
ADC result registers (ADRESH:ADRESL register pair).
Figure 15-1 shows the block diagram of the ADC.
The ADC voltage reference is software selectable to be
either internally generated or externally supplied.

FIGURE 15-1:

ADC BLOCK DIAGRAM

VDD
ADPREF = 00
VREF+

AN0

00000

VREF+/AN1

00001

AN2

00010

AN3

00011

AN4

00100

AN5

00101

AN6

00110

AN7
AN8

00111
01000

AN9

01001

AN10

01010

AN11
Reserved

01011
01100

Reserved

11100

ADPREF = 10

VREF- = VSS

VREF+

ADC
10

GO/DONE
ADFM

0 = Left Justify
1 = Right Justify

ADON

Temp Indicator

11101

DAC
FVR Buffer1

11110

16
VSS

ADRESH

ADRESL

11111

CHS<4:0>

Note 1:

When ADON = 0, all multiplexer inputs are disconnected.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 135

PIC16(L)F1508/9
15.1

ADC Configuration

15.1.4

When configuring and using the ADC the following

functions must be considered:

Port configuration
Channel selection
ADC voltage reference selection
ADC conversion clock source
Interrupt control
Result formatting

15.1.1

The ADC can be used to convert both analog and

digital signals. When converting analog signals, the I/O
pin should be configured for analog by setting the
associated TRIS and ANSEL bits. Refer to
Section 11.0 I/O Ports for more information.
Note:

15.1.2

The source of the conversion clock is software selectable via the ADCS bits of the ADCON1 register. There
are seven possible clock options:

PORT CONFIGURATION

Analog voltages on any pin that is defined

as a digital input may cause the input buffer to conduct excess current.

FOSC/2
FOSC/4
FOSC/8
FOSC/16
FOSC/32
FOSC/64
FRC (dedicated internal oscillator)

The time to complete one bit conversion is defined as

TAD. One full 10-bit conversion requires 11.5 TAD periods as shown in Figure 15-2.
For correct conversion, the appropriate TAD specification must be met. Refer to the A/D conversion requirements in Section 29.0 Electrical Specifications for
more information. Table 15-1 gives examples of appropriate ADC clock selections.
Note:

CHANNEL SELECTION

There are 15 channel selections available:

CONVERSION CLOCK

AN<11:0> pins
Temperature Indicator
DAC
FVR (Fixed Voltage Reference) Output

Unless using the FRC, any changes in the

system clock frequency will change the
ADC clock frequency, which may
adversely affect the ADC result.

Refer to Section 13.0 Fixed Voltage Reference (FVR)

and Section 14.0 Temperature Indicator Module for
more information on these channel selections.
The CHS bits of the ADCON0 register determine which
channel is connected to the sample and hold circuit.
When changing channels, a delay is required before
starting the next conversion. Refer to Section 15.2
ADC Operation for more information.

15.1.3

ADC VOLTAGE REFERENCE

The ADPREF bits of the ADCON1 register provides

control of the positive voltage reference. The positive
voltage reference can be:
VREF+ pin
VDD
See Section 13.0 Fixed Voltage Reference (FVR)
for more details on the Fixed Voltage Reference.

DS41609A-page 136

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 15-1:

ADC CLOCK PERIOD (TAD) VS. DEVICE OPERATING FREQUENCIES

ADC Clock Period (TAD)

Device Frequency (FOSC)

ADC
Clock Source

ADCS<2:0>

20 MHz

16 MHz

8 MHz

4 MHz

1 MHz

Fosc/2

000

100 ns(2)

125 ns(2)

250 ns(2)

500 ns(2)

2.0 s

Fosc/4

100

(2)

200 ns

(2)

250 ns

(2)

Fosc/8

001

400 ns(2)

0.5 s(2)

Fosc/16

101

800 ns

1.0 s

Fosc/32

1.6 s

010

2.0 s

Fosc/64

110

3.2 s

4.0 s

FRC

x11

1.0-6.0 s(1,4)

Legend:
Note 1:
2:
3:
4:

1.0 s

4.0 s

1.0 s

2.0 s

8.0 s(3)

2.0 s

4.0 s

16.0 s(3)

500 ns

4.0 s
(3)

8.0 s

1.0-6.0 s(1,4)

(3)

8.0 s

(3)

16.0 s

1.0-6.0 s(1,4)

32.0 s(3)
64.0 s(3)
1.0-6.0 s(1,4)

Shaded cells are outside of recommended range.

The FRC source has a typical TAD time of 1.6 s for VDD.
These values violate the minimum required TAD time.
For faster conversion times, the selection of another clock source is recommended.
The ADC clock period (TAD) and total ADC conversion time can be minimized when the ADC clock is derived from the
system clock FOSC. However, the FRC clock source must be used when conversions are to be performed with the
device in Sleep mode.

FIGURE 15-2:

ANALOG-TO-DIGITAL CONVERSION TAD CYCLES

TCY - TAD TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11
b4
b1
b0
b6
b7
b2
b8
b3
b9
b5
Conversion starts
Holding capacitor is disconnected from analog input (typically 100 ns)
Set GO bit
On the following cycle:
ADRESH:ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 137

PIC16(L)F1508/9
15.1.5

INTERRUPTS

15.1.6

The ADC module allows for the ability to generate an

interrupt upon completion of an Analog-to-Digital
conversion. The ADC Interrupt Flag is the ADIF bit in
the PIR1 register. The ADC Interrupt Enable is the
ADIE bit in the PIE1 register. The ADIF bit must be
cleared in software.

RESULT FORMATTING

The 10-bit A/D conversion result can be supplied in two

formats, left justified or right justified. The ADFM bit of
the ADCON1 register controls the output format.
Figure 15-3 shows the two output formats.

Note 1: The ADIF bit is set at the completion of

every conversion, regardless of whether
or not the ADC interrupt is enabled.
2: The ADC operates during Sleep only
when the FRC oscillator is selected.

This interrupt can be generated while the device is

operating or while in Sleep. If the device is in Sleep, the
interrupt will wake-up the device. Upon waking from
Sleep, the next instruction following the SLEEP instruction is always executed. If the user is attempting to
wake-up from Sleep and resume in-line code execution, the GIE and PEIE bits of the INTCON register
must be disabled. If the GIE and PEIE bits of the
INTCON register are enabled, execution will switch to
the Interrupt Service Routine.

FIGURE 15-3:

10-BIT A/D CONVERSION RESULT FORMAT

ADRESH

(ADFM = 0)

ADRESL

MSB

LSB

bit 7

bit 0

bit 7

Unimplemented: Read as 0

10-bit A/D Result

(ADFM = 1)

MSB
bit 7

LSB
bit 0

Unimplemented: Read as 0

DS41609A-page 138

bit 0

bit 7

bit 0
10-bit A/D Result

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
15.2
15.2.1

ADC Operation

15.2.4

STARTING A CONVERSION

To enable the ADC module, the ADON bit of the

ADCON0 register must be set to a 1. Setting the GO/
DONE bit of the ADCON0 register to a 1 will start the
Analog-to-Digital conversion.
Note:

15.2.2

The GO/DONE bit should not be set in the

same instruction that turns on the ADC.
Refer to Section 15.2.6 A/D Conversion Procedure.

COMPLETION OF A CONVERSION

When the conversion is complete, the ADC module will:

Clear the GO/DONE bit
Set the ADIF Interrupt Flag bit
Update the ADRESH and ADRESL registers with
new conversion result

15.2.3

TERMINATING A CONVERSION

If a conversion must be terminated before completion,

the GO/DONE bit can be cleared in software. The
ADRESH and ADRESL registers will be updated with
the partially complete Analog-to-Digital conversion
sample. Incomplete bits will match the last bit
converted.
Note:

A device Reset forces all registers to their

Reset state. Thus, the ADC module is
turned off and any pending conversion is
terminated.

2011 Microchip Technology Inc.

ADC OPERATION DURING SLEEP

The ADC module can operate during Sleep. This

requires the ADC clock source to be set to the FRC
option. When the FRC clock source is selected, the
ADC waits one additional instruction before starting the
conversion. This allows the SLEEP instruction to be
executed, which can reduce system noise during the
conversion. If the ADC interrupt is enabled, the device
will wake-up from Sleep when the conversion
completes. If the ADC interrupt is disabled, the ADC
module is turned off after the conversion completes,
although the ADON bit remains set.
When the ADC clock source is something other than
FRC, a SLEEP instruction causes the present conversion to be aborted and the ADC module is turned off,
although the ADON bit remains set.

15.2.5

AUTO-CONVERSION TRIGGER

The auto-conversion trigger allows periodic ADC measurements without software intervention. When a rising
edge of the selected source occurs, the GO/DONE bit
is set by hardware.
The auto-conversion trigger source is selected with the
TRIGSEL<3:0> bits of the ADCON2 register.
Using the auto-conversion trigger does not assure
proper ADC timing. It is the users responsibility to
ensure that the ADC timing requirements are met.
Auto-Conversion sources are:

TMR0
TMR1
TMR2
C1
C2
CLC1
CLC2
CLC3
CLC4

Preliminary

DS41609A-page 139

PIC16(L)F1508/9
15.2.6

A/D CONVERSION PROCEDURE

EXAMPLE 15-1:

This is an example procedure for using the ADC to

perform an Analog-to-Digital conversion:
1.

4.
5.
6.

7.
8.

Configure Port:
Disable pin output driver (Refer to the TRIS
register)
Configure pin as analog (Refer to the ANSEL
register)
Configure the ADC module:
Select ADC conversion clock
Configure voltage reference
Select ADC input channel
Turn on ADC module
Configure ADC interrupt (optional):
Clear ADC interrupt flag
Enable ADC interrupt
Enable peripheral interrupt
Enable global interrupt(1)
Wait the required acquisition time(2).
Start conversion by setting the GO/DONE bit.
Wait for ADC conversion to complete by one of
the following:
Polling the GO/DONE bit
Waiting for the ADC interrupt (interrupts
enabled)
Read ADC Result.
Clear the ADC interrupt flag (required if interrupt
is enabled).

A/D CONVERSION

;This code block configures the ADC

;for polling, Vdd and Vss references, Frc
;clock and AN0 input.
;
;Conversion start & polling for completion
; are included.
;
BANKSEL
ADCON1
;
MOVLW
B11110000 ;Right justify, Frc
;clock
MOVWF
ADCON1
;Vdd and Vss Vref+
BANKSEL
TRISA
;
BSF
TRISA,0
;Set RA0 to input
BANKSEL
ANSEL
;
BSF
ANSEL,0
;Set RA0 to analog
BANKSEL
ADCON0
;
MOVLW
B00000001 ;Select channel AN0
MOVWF
ADCON0
;Turn ADC On
CALL
SampleTime
;Acquisiton delay
BSF
ADCON0,ADGO ;Start conversion
BTFSC
ADCON0,ADGO ;Is conversion done?
GOTO
$-1
;No, test again
BANKSEL
ADRESH
;
MOVF
ADRESH,W
;Read upper 2 bits
MOVWF
RESULTHI
;store in GPR space
BANKSEL
ADRESL
;
MOVF
ADRESL,W
;Read lower 8 bits
MOVWF
RESULTLO
;Store in GPR space

Note 1: The global interrupt can be disabled if the

user is attempting to wake-up from Sleep
and resume in-line code execution.
2: Refer to Section 15.3 A/D Acquisition
Requirements.

DS41609A-page 140

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2011 Microchip Technology Inc.

PIC16(L)F1508/9
15.2.7

ADC REGISTER DEFINITIONS

The following registers are used to control the

operation of the ADC.

ADCON0: A/D CONTROL REGISTER 0

R/W-0/0

CHS<4:0>

R/W-0/0

GO/DONE

ADON

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

Unimplemented: Read as 0

bit 6-2

11100 = Reserved. No channel connected.

11101 = Temperature Indicator(1)
11110 = DAC (Digital-to-Analog Converter)(2)
11111 = FVR (Fixed Voltage Reference) Buffer 1 Output(3)

bit 1

GO/DONE: A/D Conversion Status bit

1 = A/D conversion cycle in progress. Setting this bit starts an A/D conversion cycle.
This bit is automatically cleared by hardware when the A/D conversion has completed.
0 = A/D conversion completed/not in progress

bit 0

ADON: ADC Enable bit

1 = ADC is enabled
0 = ADC is disabled and consumes no operating current

Note 1:
2:
3:

See Section 14.0 Temperature Indicator Module for more information.

See Section 16.0 Digital-to-Analog Converter (DAC) Module for more information.
See Section 13.0 Fixed Voltage Reference (FVR) for more information.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 141

PIC16(L)F1508/9
REGISTER 15-2:
R/W-0/0

ADCON1: A/D CONTROL REGISTER 1

R/W-0/0

ADFM

R/W-0/0

ADCS<2:0>

U-0

R/W-0/0

ADPREF<1:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

ADFM: A/D Result Format Select bit

1 = Right justified. Six Most Significant bits of ADRESH are set to 0 when the conversion result is
loaded.
0 = Left justified. Six Least Significant bits of ADRESL are set to 0 when the conversion result is
loaded.

bit 6-4

ADCS<2:0>: A/D Conversion Clock Select bits

000 = FOSC/2
001 = FOSC/8
010 = FOSC/32
011 = FRC (clock supplied from a dedicated RC oscillator)
100 = FOSC/4
101 = FOSC/16
110 = FOSC/64
111 = FRC (clock supplied from a dedicated RC oscillator)

bit 3-2

Unimplemented: Read as 0

bit 1-0

ADPREF<1:0>: A/D Positive Voltage Reference Configuration bits

00 = VREF+ is connected to VDD
01 = Reserved
10 = VREF+ is connected to external VREF+ pin(1)
11 = Reserved

Note 1:

When selecting the VREF+ pin as the source of the positive reference, be aware that a minimum voltage
specification exists. See Section 29.0 Electrical Specifications for details.

DS41609A-page 142

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 15-3:
R/W-0/0

ADCON2: A/D CONTROL REGISTER 2

R/W-0/0

TRIGSEL<3:0>

U-0

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

TRIGSEL<3:0>: Auto-Conversion Trigger Selection bits(1)

0000 = No auto-conversion trigger selected
0001 = Reserved
0010 = Reserved
0011 = TMR0 Overflow(2)
0100 = TMR1 Overflow(2)
0101 = TMR2 Match to PR2(2)
0110 = SYNCC1OUT
0111 = SYNCC2OUT
1000 = CLC1
1001 = CLC2
1010 = CLC3
1011 = CLC4
1100 = Reserved
1101 = Reserved
1110 = Reserved
1111 = Reserved

bit 3-0

Unimplemented: Read as 0

Note 1:
2:

This is a rising edge sensitive input for all sources.

Signal also sets its corresponding interrupt flag.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 143

PIC16(L)F1508/9
REGISTER 15-4:
R/W-x/u

ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 0

R/W-x/u

ADRES<9:2>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

ADRES<9:2>: ADC Result Register bits

Upper 8 bits of 10-bit conversion result

ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 0

R/W-x/u

ADRES<1:0>

R/W-x/u

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

ADRES<1:0>: ADC Result Register bits

Lower 2 bits of 10-bit conversion result

bit 5-0

Reserved: Do not use.

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Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 15-6:

ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 1

R/W-x/u

ADRES<9:8>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-2

Reserved: Do not use.

bit 1-0

ADRES<9:8>: ADC Result Register bits

Upper 2 bits of 10-bit conversion result

ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 1

R/W-x/u

ADRES<7:0>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

ADRES<7:0>: ADC Result Register bits

Lower 8 bits of 10-bit conversion result

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 145

PIC16(L)F1508/9
15.3

A/D Acquisition Requirements

For the ADC to meet its specified accuracy, the charge

holding capacitor (CHOLD) must be allowed to fully
charge to the input channel voltage level. The Analog
Input model is shown in Figure 15-4. The source
impedance (RS) and the internal sampling switch (RSS)
impedance directly affect the time required to charge
the capacitor CHOLD. The sampling switch (RSS)
impedance varies over the device voltage (VDD), refer
to Figure 15-4. The maximum recommended
impedance for analog sources is 10 k. As the

EQUATION 15-1:
Assumptions:

source impedance is decreased, the acquisition time

may be decreased. After the analog input channel is
selected (or changed), an A/D acquisition must be
done before the conversion can be started. To calculate
the minimum acquisition time, Equation 15-1 may be
used. This equation assumes that 1/2 LSb error is used
(1,024 steps for the ADC). The 1/2 LSb error is the
maximum error allowed for the ADC to meet its
specified resolution.

ACQUISITION TIME EXAMPLE

Temperature = 50C and external impedance of 10k 5.0V V DD

T ACQ = Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient
= T AMP + T C + T COFF
= 2s + T C + Temperature - 25C 0.05s/C
The value for TC can be approximated with the following equations:

1
= V CHOLD
V AP P LI ED 1 -------------------------n+1

2
1

;[1] VCHOLD charged to within 1/2 lsb

----------

RC
V AP P LI ED 1 e = V CHOLD

;[2] VCHOLD charge response to VAPPLIED

---------

1
RC
;combining [1] and [2]
V AP P LI ED 1 e = V A PP LIE D 1 -------------------------n+1

2
1

Note: Where n = number of bits of the ADC.

Solving for TC:

T C = C HOLD R IC + R SS + R S ln(1/2047)
= 12.5pF 1k + 7k + 10k ln(0.0004885)
= 1.12 s
Therefore:
T A CQ = 5s + 1.12 s + 50C- 25C 0.05 s/C
= 7.37s

Note 1: The reference voltage (VREF+) has no effect on the equation, since it cancels itself out.
2: The charge holding capacitor (CHOLD) is not discharged after each conversion.
3: The maximum recommended impedance for analog sources is 10 k. This is required to meet the pin
leakage specification.

DS41609A-page 146

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 15-4:

ANALOG INPUT MODEL

VDD

Analog
Input
pin

VT 0.6V

CPIN
5 pF

RIC 1k

Sampling
Switch
SS Rss

I LEAKAGE(1)

VT 0.6V

CHOLD = 10 pF
VREF-

Legend: CHOLD
CPIN

6V
5V
VDD 4V
3V
2V

= Sample/Hold Capacitance
= Input Capacitance

RSS

I LEAKAGE = Leakage current at the pin due to

various junctions
RIC
= Interconnect Resistance
RSS
= Resistance of Sampling Switch
SS

= Sampling Switch

= Threshold Voltage

Note 1:

FIGURE 15-5:

5 6 7 8 9 10 11
Sampling Switch
(k)

Refer to Section 29.0 Electrical Specifications.

ADC TRANSFER FUNCTION

Full-Scale Range

3FFh
3FEh

ADC Output Code

3FDh
3FCh
3FBh

03h
02h
01h
00h

Analog Input Voltage

0.5 LSB

VREF-

2011 Microchip Technology Inc.

1.5 LSB

Zero-Scale
Transition

Full-Scale
Transition

Preliminary

VREF+

DS41609A-page 147

PIC16(L)F1508/9
TABLE 15-2:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH ADC

Bit 7

ADCON0

ADCON1

ADFM

ADCON2

Bit 6

Bit 5

Bit 4

TRIGSEL<3:0>
A/D Result Register High

ADRESL

A/D Result Register Low

Bit 2

ADPREF<1:0>

CHS<4:0>
ADCS<2:0>

ADRESH
ANSELA

Bit 3

Bit 1

Bit 0

GO/DONE

ADON

ANSA4

ANSA2

ANSA1

ANSA0

115

ANSELB

ANSB5

ANSB4

119

ANSELC

ANSC7

ANSC6

ANSC3

ANSC2

ANSC1

ANSC0

123

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

TRISA5

TRISA4

(1)

TRISA2

TRISA1

TRISA0

114

INTCON

TRISA
TRISB

TRISB7

TRISB6

TRISB5

TRISB4

118

TRISC

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

FVREN

FVRRDY

TSEN

TSRNG

FVRCON

Legend:
Note 1:

CDAFVR<1:0>

ADFVR<1:0>

132

x = unknown, u = unchanged, = unimplemented read as 0, q = value depends on condition. Shaded cells are not
used for ADC module.
Unimplemented, read as 1.

DS41609A-page 148

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
16.0

DIGITAL-TO-ANALOG
CONVERTER (DAC) MODULE

The Digital-to-Analog Converter supplies a variable

voltage reference, ratiometric with the input source,
with 32 selectable output levels.
The input of the DAC can be connected to:

16.1

Output Voltage Selection

The DAC has 32 voltage level ranges. The 32 levels

are set with the DACR<4:0> bits of the DACCON1
register.
The DAC output voltage is determined by the following
equations:

External VREF+ pin

VDD supply voltage
The output of the DAC can be configured to supply a
reference voltage to the following:

Comparator positive input

ADC input channel
DACOUT1 pin
DACOUT2 pin

The Digital-to-Analog Converter (DAC) can be enabled

by setting the DACEN bit of the DACCON0 register.

EQUATION 16-1:

DAC OUTPUT VOLTAGE

IF DACEN = 1
DACR 4:0
VOUT = VSOURCE+ VSOURCE- ----------------------------+ VSOURCE5

2
IF DACEN = 0 and DACLPS = 1 and DACR[4:0] = 11111
V OUT = V SOURCE +
IF DACEN = 0 and DACLPS = 0 and DACR[4:0] = 00000
V OUT = V SOURCE
VSOURCE+ = VDD, VREF, or FVR BUFFER 2
VSOURCE- = VSS

16.2

Ratiometric Output Level

16.3

The DAC output value is derived using a resistor ladder

with each end of the ladder tied to a positive and
negative voltage reference input source. If the voltage
of either input source fluctuates, a similar fluctuation will
result in the DAC output value.
The value of the individual resistors within the ladder
can be found in Section 29.0 Electrical
Specifications.

DAC Voltage Reference Output

The DAC voltage can be output to the DACOUT1 and

DACOUT2 pins by setting the respective DACOE1 and
DACOE2 pins of the DACCON0 register. Selecting the
DAC reference voltage for output on either DACOUTx
pin automatically overrides the digital output buffer and
digital input threshold detector functions of that pin.
Reading the DACOUTx pin when it has been configured for DAC reference voltage output will always
return a 0.
Due to the limited current drive capability, a buffer must
be used on the DAC voltage reference output for
external connections to either DACOUTx pin.
Figure 16-2 shows an example buffering technique.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 149

PIC16(L)F1508/9
FIGURE 16-1:

DIGITAL-TO-ANALOG CONVERTER BLOCK DIAGRAM

Digital-to-Analog Converter (DAC)

VSOURCE+

VDD

DACR<4:0>

VREF+

R
R

DACPSS

DACEN

R
32
Steps
R

32-to-1 MUX

DAC
(To Comparator and
ADC Module)

DACOUT1

DACOE1

VSOURCE-

DACOUT2
DACOE2

FIGURE 16-2:

VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE

PIC MCU

DAC
Module

R
Voltage
Reference
Output
Impedance

DS41609A-page 150

DACOUTX

Preliminary

Buffered DAC Output

2011 Microchip Technology Inc.

PIC16(L)F1508/9
16.4

Operation During Sleep

When the device wakes up from Sleep through an

interrupt or a Watchdog Timer time-out, the contents of
the DACCON0 register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.

16.5

Effects of a Reset

A device Reset affects the following:

DAC is disabled.
DAC output voltage is removed from the
DACOUT pin.
The DACR<4:0> range select bits are cleared.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 151

PIC16(L)F1508/9
16.6

DAC Control Registers

DACCON0: VOLTAGE REFERENCE CONTROL REGISTER 0

R/W-0/0

U-0

R/W-0/0

U-0

R/W-0/0

U-0

DACEN

DACOE1

DACOE2

DACPSS

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

DACEN: DAC Enable bit

1 = DAC is enabled
0 = DAC is disabled

bit 6

Unimplemented: Read as 0

bit 5

DACOE1: DAC Voltage Output Enable bit

1 = DAC voltage level is also an output on the DACOUT1 pin
0 = DAC voltage level is disconnected from the DACOUT1 pin

bit 4

DACOE2: DAC Voltage Output Enable bit

1 = DAC voltage level is also an output on the DACOUT2 pin
0 = DAC voltage level is disconnected from the DACOUT2 pin

bit 3

Unimplemented: Read as 0

bit 2

DACPSS: DAC Positive Source Select bit

1=
VREF+ pin
0=
VDD

bit 1-0

Unimplemented: Read as 0

DACCON1: VOLTAGE REFERENCE CONTROL REGISTER 1

U-0

R/W-0/0

DACR<4:0>

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-5

Unimplemented: Read as 0

bit 4-0

DACR<4:0>: DAC Voltage Output Select bits

TABLE 16-1:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH THE DAC MODULE

Bit 7

Bit 6

FVRCON

FVREN

FVRRDY

TSEN

TSRNG

CDAFVR<1:0>

DACCON0

DACEN

DACOE1

DACOE2

DACCON1

Legend:

Bit 5

Bit 4

Bit 3

Bit 2

DACPSS

Bit 1

Bit 0

ADFVR<1:0>

DACR<4:0>

= Unimplemented location, read as 0. Shaded cells are not used with the DAC module.

DS41609A-page 152

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
17.0

COMPARATOR MODULE

FIGURE 17-1:

Comparators are used to interface analog circuits to a

digital circuit by comparing two analog voltages and
providing a digital indication of their relative magnitudes.
Comparators are very useful mixed signal building
blocks because they provide analog functionality
independent of program execution. The analog
comparator module includes the following features:

Independent comparator control

Programmable input selection
Comparator output is available internally/externally
Programmable output polarity
Interrupt-on-change
Wake-up from Sleep
Programmable Speed/Power optimization
PWM shutdown
Programmable and Fixed Voltage Reference

17.1

SINGLE COMPARATOR

VIN+

VIN-

Output

VINVIN+

Output

Note:

Comparator Overview

The black areas of the output of the

comparator represents the uncertainty
due to input offsets and response time.

A single comparator is shown in Figure 17-1 along with

the relationship between the analog input levels and
the digital output. When the analog voltage at VIN+ is
less than the analog voltage at VIN-, the output of the
comparator is a digital low level. When the analog
voltage at VIN+ is greater than the analog voltage at
VIN-, the output of the comparator is a digital high level.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 153

PIC16(L)F1508/9
FIGURE 17-2:

COMPARATOR MODULES SIMPLIFIED BLOCK DIAGRAM

CxNCH<2:0>

CxON(1)

3
C12IN0-

C12IN1C12IN2-

1
MUX
2 (2)

C12IN3-

FVR Buffer2

det
Set CxIF

0
MUX
1 (2)

DAC
FVR Buffer2

CxINTN

Interrupt
det
CXPOL
CxVN

Cx
CxVP

CXIN+

CxINTP

Interrupt

CXOUT
MCXOUT

+
EN

Q1
CxHYS
CxSP

async_CxOUT

2
3

CXSYNC

CxON
CXPCH<1:0>

To CWG

CXOE

TRIS bit
CXOUT

2
D

(from Timer1)
T1CLK
SYNCCXOUT
Note

1:
2:

When CxON = 0, the Comparator will produce a 0 at the output

When CxON = 0, all multiplexer inputs are disconnected.

DS41609A-page 154

Preliminary

To Timer1,
CLCx, ADC

2011 Microchip Technology Inc.

PIC16(L)F1508/9
17.2

Comparator Control

17.2.3

Each comparator has 2 control registers: CMxCON0 and

CMxCON1.
The CMxCON0 registers (see Register 17-1) contain
Control and Status bits for the following:

Enable
Output selection
Output polarity
Speed/Power selection
Hysteresis enable
Output synchronization

Inverting the output of the comparator is functionally

equivalent to swapping the comparator inputs. The
polarity of the comparator output can be inverted by
setting the CxPOL bit of the CMxCON0 register.
Clearing the CxPOL bit results in a non-inverted output.
Table 17-1 shows the output state versus input
conditions, including polarity control.

TABLE 17-1:

Interrupt enable
Interrupt edge polarity
Positive input channel selection
Negative input channel selection

17.2.1

CxPOL

CxOUT

CxVN > CxVP

CxVN < CxVP

CxVN > CxVP

CxVN < CxVP

17.2.4

COMPARATOR ENABLE

Setting the CxON bit of the CMxCON0 register enables

the comparator for operation. Clearing the CxON bit
disables the comparator resulting in minimum current
consumption.

17.2.2

COMPARATOR OUTPUT
SELECTION

COMPARATOR OUTPUT
STATE VS. INPUT
CONDITIONS

Input Condition

The CMxCON1 registers (see Register 17-2) contain

Control bits for the following:

COMPARATOR OUTPUT POLARITY

COMPARATOR SPEED/POWER
SELECTION

The trade-off between speed or power can be optimized during program execution with the CxSP control
bit. The default state for this bit is 1 which selects the
normal speed mode. Device power consumption can
be optimized at the cost of slower comparator propagation delay by clearing the CxSP bit to 0.

The output of the comparator can be monitored by

reading either the CxOUT bit of the CMxCON0 register
or the MCxOUT bit of the CMOUT register. In order to
make the output available for an external connection,
the following conditions must be true:
CxOE bit of the CMxCON0 register must be set
Corresponding TRIS bit must be cleared
CxON bit of the CMxCON0 register must be set
Note 1: The CxOE bit of the CMxCON0 register
overrides the PORT data latch. Setting
the CxON bit of the CMxCON0 register
has no impact on the port override.
2: The internal output of the comparator is
latched with each instruction cycle.
Unless otherwise specified, external
outputs are not latched.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 155

PIC16(L)F1508/9
17.3

Comparator Hysteresis

17.5

A selectable amount of separation voltage can be

added to the input pins of each comparator to provide a
hysteresis function to the overall operation. Hysteresis
is enabled by setting the CxHYS bit of the CMxCON0
register.

Comparator Interrupt

An interrupt can be generated upon a change in the

output value of the comparator for each comparator, a
rising edge detector and a falling edge detector are
present.

See Section 29.0 Electrical Specifications for

more information.

When either edge detector is triggered and its associated enable bit is set (CxINTP and/or CxINTN bits of
the CMxCON1 register), the Corresponding Interrupt
Flag bit (CxIF bit of the PIR2 register) will be set.

17.4

To enable the interrupt, you must set the following bits:

Timer1 Gate Operation

The output resulting from a comparator operation can

be used as a source for gate control of Timer1. See
Section 19.5 Timer1 Gate for more information.
This feature is useful for timing the duration or interval
of an analog event.
It is recommended that the comparator output be synchronized to Timer1. This ensures that Timer1 does not
increment while a change in the comparator is occurring.

17.4.1

COMPARATOR OUTPUT
SYNCHRONIZATION

The output from either comparator, C1 or C2, can be

synchronized with Timer1 by setting the CxSYNC bit of
the CMxCON0 register.
Once enabled, the comparator output is latched on the
falling edge of the Timer1 source clock. If a prescaler is
used with Timer1, the comparator output is latched after
the prescaling function. To prevent a race condition, the
comparator output is latched on the falling edge of the
Timer1 clock source and Timer1 increments on the
rising edge of its clock source. See the Comparator
Block Diagram (Figure 17-2) and the Timer1 Block
Diagram (Figure 19-1) for more information.

CxON, CxPOL and CxSP bits of the CMxCON0

register
CxIE bit of the PIE2 register
CxINTP bit of the CMxCON1 register (for a rising
edge detection)
CxINTN bit of the CMxCON1 register (for a falling
edge detection)
PEIE and GIE bits of the INTCON register
The associated interrupt flag bit, CxIF bit of the PIR2
register, must be cleared in software. If another edge is
detected while this flag is being cleared, the flag will still
be set at the end of the sequence.
Note:

17.6

Although a comparator is disabled, an

interrupt can be generated by changing
the output polarity with the CxPOL bit of
the CMxCON0 register, or by switching
the comparator on or off with the CxON bit
of the CMxCON0 register.

Comparator Positive Input

Selection

Configuring the CxPCH<1:0> bits of the CMxCON1

CxIN+ analog pin

DAC
FVR (Fixed Voltage Reference)
VSS (Ground)

See Section 13.0 Fixed Voltage Reference (FVR)

for more information on the Fixed Voltage Reference
module.
See Section 16.0 Digital-to-Analog Converter
(DAC) Module for more information on the DAC input
signal.
Any time the comparator is disabled (CxON = 0), all
comparator inputs are disabled.

DS41609A-page 156

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
17.7

Comparator Negative Input

Selection

17.10 Analog Input Connection

Considerations

The CxNCH<2:0> bits of the CMxCON0 register direct

one of the input sources to the comparator inverting
input.
Note:

17.8

To use CxIN+ and CxINx- pins as analog

input, the appropriate bits must be set in
the ANSEL register and the corresponding TRIS bits must also be set to disable
the output drivers.

Comparator Response Time

The comparator output is indeterminate for a period of

time after the change of an input source or the selection
of a new reference voltage. This period is referred to as
the response time. The response time of the comparator
differs from the settling time of the voltage reference.
Therefore, both of these times must be considered when
determining the total response time to a comparator
input change. See the Comparator and Voltage Reference Specifications in Section 29.0 Electrical Specifications for more details.

17.9

A simplified circuit for an analog input is shown in

Figure 17-3. Since the analog input pins share their
connection with a digital input, they have reverse
biased ESD protection diodes to VDD and VSS. The
analog input, therefore, must be between VSS and VDD.
If the input voltage deviates from this range by more
than 0.6V in either direction, one of the diodes is forward biased and a latch-up may occur.
A maximum source impedance of 10 k is recommended
for the analog sources. Also, any external component
connected to an analog input pin, such as a capacitor or
a Zener diode, should have very little leakage current to
minimize inaccuracies introduced.
Note 1: When reading a PORT register, all pins
configured as analog inputs will read as a
0. Pins configured as digital inputs will
convert as an analog input, according to
the input specification.

Interaction with ECCP Logic

2: Analog levels on any pin defined as a

digital input, may cause the input buffer to
consume more current than is specified.

The C1 and C2 comparators can be used as general

purpose comparators. Their outputs can be brought
out to the C1OUT and C2OUT pins. When the ECCP
Auto-Shutdown is active it can use one or both
comparator signals. If auto-restart is also enabled, the
comparators can be configured as a closed loop
analog feedback to the ECCP, thereby, creating an
analog controlled PWM.
Note:

When the comparator module is first

initialized the output state is unknown.
Upon initialization, the user should verify
the output state of the comparator prior to
relying on the result, primarily when using
the result in connection with other
peripheral features, such as the ECCP
Auto-Shutdown mode.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 157

PIC16(L)F1508/9
FIGURE 17-3:

ANALOG INPUT MODEL

VDD

Rs < 10K

Analog
Input
pin

VT 0.6V

RIC
To Comparator

CPIN
5 pF

VT 0.6V

ILEAKAGE(1)

Vss
Legend: CPIN
= Input Capacitance
ILEAKAGE = Leakage Current at the pin due to various junctions
= Interconnect Resistance
RIC
= Source Impedance
RS
= Analog Voltage
VA
= Threshold Voltage
VT
Note 1:

DS41609A-page 158

See Section 29.0 Electrical Specifications.

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 17-1:

CMxCON0: COMPARATOR Cx CONTROL REGISTER 0

R/W-0/0

R-0/0

R/W-0/0

U-0

R/W-1/1

R/W-0/0

CxON

CxOUT

CxOE

CxPOL

CxSP

CxHYS

CxSYNC

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

CxON: Comparator Enable bit

1 = Comparator is enabled and consumes no active power
0 = Comparator is disabled

bit 6

CxOUT: Comparator Output bit

If CxPOL = 1 (inverted polarity):
1 = CxVP < CxVN
0 = CxVP > CxVN
If CxPOL = 0 (non-inverted polarity):
1 = CxVP > CxVN
0 = CxVP < CxVN

bit 5

CxOE: Comparator Output Enable bit

1 = CxOUT is present on the CxOUT pin. Requires that the associated TRIS bit be cleared to actually
drive the pin. Not affected by CxON.
0 = CxOUT is internal only

bit 4

CxPOL: Comparator Output Polarity Select bit

1 = Comparator output is inverted
0 = Comparator output is not inverted

bit 3

Unimplemented: Read as 0

bit 2

CxSP: Comparator Speed/Power Select bit

1 = Comparator operates in normal power, higher speed mode
0 = Comparator operates in low-power, low-speed mode

bit 1

CxHYS: Comparator Hysteresis Enable bit

1 = Comparator hysteresis enabled
0 = Comparator hysteresis disabled

bit 0

CxSYNC: Comparator Output Synchronous Mode bit

1 = Comparator output to Timer1 and I/O pin is synchronous to changes on Timer1 clock source.
Output updated on the falling edge of Timer1 clock source.
0 = Comparator output to Timer1 and I/O pin is asynchronous

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 159

PIC16(L)F1508/9
REGISTER 17-2:

CMxCON1: COMPARATOR Cx CONTROL REGISTER 1

R/W-0/0

CxINTP

CxINTN

R/W-0/0

CxPCH<1:0>

U-0

R/W-0/0

CxNCH<2:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

CxINTP: Comparator Interrupt on Positive Going Edge Enable bits

1 = The CxIF interrupt flag will be set upon a positive going edge of the CxOUT bit
0 = No interrupt flag will be set on a positive going edge of the CxOUT bit

bit 6

CxINTN: Comparator Interrupt on Negative Going Edge Enable bits

1 = The CxIF interrupt flag will be set upon a negative going edge of the CxOUT bit
0 = No interrupt flag will be set on a negative going edge of the CxOUT bit

bit 5-4

CxPCH<1:0>: Comparator Positive Input Channel Select bits

11 = CxVP connects to VSS
10 = CxVP connects to FVR Voltage Reference
01 = CxVP connects to DAC Voltage Reference
00 = CxVP connects to CxIN+ pin

bit 3

Unimplemented: Read as 0

bit 2-0

CMOUT: COMPARATOR OUTPUT REGISTER

U-0

R-0/0

MC2OUT

MC1OUT

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-2

Unimplemented: Read as 0

bit 1

MC2OUT: Mirror Copy of C2OUT bit

bit 0

MC1OUT: Mirror Copy of C1OUT bit

DS41609A-page 160

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 17-2:

SUMMARY OF REGISTERS ASSOCIATED WITH COMPARATOR MODULE

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ANSELA

ANSA4

ANSA2

ANSA1

ANSA0

115

ANSELC

ANSC7

ANSC6

ANSC3

ANSC2

ANSC1

ANSC0

123

CM1CON0

C1ON

C1OUT

C1OE

C1POL

C1SP

C1HYS

C1SYNC

159

C2OE

C2POL

C2SP

C2HYS

C2SYNC

159

Name

CM2CON0

C2ON

C2OUT

CM1CON1

C1NTP

C1INTN

CM2CON1

C2NTP

C2INTN

MC2OUT

MC1OUT

160

DACCON0

DACEN

DACOE1

DACOE2

DACPSS

152

DACCON1

FVRCON

FVREN

FVRRDY

TSEN

TSRNG

INTCON

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

PIE2

OSFIE

C2IE

C1IE

BCL1IE

NCO1IE

PIR2

CMOUT

C1PCH<1:0>

C2PCH<1:0>

C1NCH<2:0>

160

C2NCH<2:0>

160

DACR<4:0>
CDAFVR<1:0>

152
ADFVR<1:0>

132

OSFIF

C2IF

C1IF

BCL1IF

NCO1IF

PORTA

RA5

RA4

RA3

RA2

RA1

RA0

114

PORTC

122

RC7

RC6

RC5

RC4

RC3

RC2

RC1

RC0

LATA

LATA5

LATA4

LATA2

LATA1

LATA0

115

LATC

LATC7

LATC6

LATC5

LATC4

LATC3

LATC2

LATC1

LATC0

122

TRISA

TRISA5

TRISA4

(1)

TRISA2

TRISA1

TRISA0

114

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

TRISC

Legend:
Note 1:

= unimplemented location, read as 0. Shaded cells are unused by the comparator module.
Unimplemented, read as 1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 161

PIC16(L)F1508/9
NOTES:

DS41609A-page 162

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
18.0

TIMER0 MODULE

18.1.2

8-BIT COUNTER MODE

The Timer0 module is an 8-bit timer/counter with the

following features:

In 8-Bit Counter mode, the Timer0 module will increment

on every rising or falling edge of the T0CKI pin.

8-Bit Counter mode using the T0CKI pin is selected by

setting the TMR0CS bit in the OPTION_REG register to
1.

8-bit timer/counter register (TMR0)

8-bit prescaler (independent of Watchdog Timer)
Programmable internal or external clock source
Programmable external clock edge selection
Interrupt on overflow
TMR0 can be used to gate Timer1

The rising or falling transition of the incrementing edge

for either input source is determined by the TMR0SE bit
in the OPTION_REG register.

Figure 18-1 is a block diagram of the Timer0 module.

18.1

Timer0 Operation

The Timer0 module can be used as either an 8-bit timer

or an 8-bit counter.

18.1.1

8-BIT TIMER MODE

The Timer0 module will increment every instruction

cycle, if used without a prescaler. 8-Bit Timer mode is
selected by clearing the TMR0CS bit of the
OPTION_REG register.
When TMR0 is written, the increment is inhibited for
two instruction cycles immediately following the write.
Note:

The value written to the TMR0 register

can be adjusted, in order to account for
the two instruction cycle delay when
TMR0 is written.

FIGURE 18-1:

BLOCK DIAGRAM OF THE TIMER0

FOSC/4
Data Bus

0
T0CKI

1
1

8
Sync
2 TCY

TMR0

0
TMR0SE TMR0CS

8-bit
Prescaler

PSA

Set Flag bit TMR0IF

on Overflow
Overflow to Timer1

PS<2:0>

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 163

PIC16(L)F1508/9
18.1.3

SOFTWARE PROGRAMMABLE
PRESCALER

A software programmable prescaler is available for

exclusive use with Timer0. The prescaler is enabled by
clearing the PSA bit of the OPTION_REG register.
Note:

The Watchdog Timer (WDT) uses its own

independent prescaler.

There are 8 prescaler options for the Timer0 module

ranging from 1:2 to 1:256. The prescale values are
selectable via the PS<2:0> bits of the OPTION_REG
register. In order to have a 1:1 prescaler value for the
Timer0 module, the prescaler must be disabled by setting the PSA bit of the OPTION_REG register.
The prescaler is not readable or writable. All instructions
writing to the TMR0 register will clear the prescaler.

18.1.4

TIMER0 INTERRUPT

Timer0 will generate an interrupt when the TMR0

register overflows from FFh to 00h. The TMR0IF
interrupt flag bit of the INTCON register is set every
time the TMR0 register overflows, regardless of
whether or not the Timer0 interrupt is enabled. The
TMR0IF bit can only be cleared in software. The Timer0
interrupt enable is the TMR0IE bit of the INTCON
register.
Note:

18.1.5

The Timer0 interrupt cannot wake the

processor from Sleep since the timer is
frozen during Sleep.
8-BIT COUNTER MODE
SYNCHRONIZATION

When in 8-Bit Counter mode, the incrementing edge on

the T0CKI pin must be synchronized to the instruction
clock. Synchronization can be accomplished by
sampling the prescaler output on the Q2 and Q4 cycles
of the instruction clock. The high and low periods of the
external clocking source must meet the timing
requirements as shown in Section 29.0 Electrical
Specifications.

18.1.6

OPERATION DURING SLEEP

Timer0 cannot operate while the processor is in Sleep

mode. The contents of the TMR0 register will remain
unchanged while the processor is in Sleep mode.

DS41609A-page 164

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
18.2

Option and Timer0 Control Register

OPTION_REG: OPTION REGISTER

R/W-1/1

WPUEN

INTEDG

TMR0CS

TMR0SE

PSA

R/W-1/1

PS<2:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

WPUEN: Weak Pull-Up Enable bit

1 = All weak pull-ups are disabled (except MCLR, if it is enabled)
0 = Weak pull-ups are enabled by individual WPUx latch values

bit 6

INTEDG: Interrupt Edge Select bit

1 = Interrupt on rising edge of INT pin
0 = Interrupt on falling edge of INT pin

bit 5

TMR0CS: Timer0 Clock Source Select bit

1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (FOSC/4)

bit 4

TMR0SE: Timer0 Source Edge Select bit

1 = Increment on high-to-low transition on T0CKI pin
0 = Increment on low-to-high transition on T0CKI pin

bit 3

PSA: Prescaler Assignment bit

1 = Prescaler is not assigned to the Timer0 module
0 = Prescaler is assigned to the Timer0 module

bit 2-0

PS<2:0>: Prescaler Rate Select bits

TABLE 18-1:
Name

Bit Value

Timer0 Rate

000
001
010
011
100
101
110
111

1:2
1:4
1:8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256

SUMMARY OF REGISTERS ASSOCIATED WITH TIMER0

Bit 7

Bit 6

ADCON2
INTCON
TMR0

Legend:
*
Note 1:

Bit 4

TRIGSEL<3:0>

OPTION_REG
TRISA

Bit 5

Bit 3

Bit 2

Bit 1

Bit 0

143

TMR0IF

INTF

IOCIF

GIE

PEIE

TMR0IE

INTE

IOCIE

WPUEN

INTEDG

TMR0CS

TMR0SE

PSA

PS<2:0>

Holding Register for the 8-bit Timer0 Count

TRISA5

TRISA4

78
165
163*

(1)

TRISA2

TRISA1

TRISA0

114

= Unimplemented location, read as 0. Shaded cells are not used by the Timer0 module.
Page provides register information.
Unimplemented, read as 1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 165

PIC16(L)F1508/9
NOTES:

DS41609A-page 166

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
19.0

TIMER1 MODULE WITH GATE

CONTROL

Gate Single-Pulse mode

Gate Value Status
Gate Event Interrupt

The Timer1 module is a 16-bit timer/counter with the

following features:

Figure 19-1 is a block diagram of the Timer1 module.

16-bit timer/counter register pair (TMR1H:TMR1L)

Programmable internal or external clock source
2-bit prescaler
Optionally synchronized comparator out
Multiple Timer1 gate (count enable) sources
Interrupt on overflow
Wake-up on overflow (external clock,
Asynchronous mode only)
Special Event Trigger
Selectable Gate Source Polarity
Gate Toggle mode

FIGURE 19-1:

TIMER1 BLOCK DIAGRAM

T1GSS<1:0>
T1GSPM

T1G

From Timer0
Overflow

SYNCC1OUT

SYNCC2OUT

t1g_in

Single Pulse

TMR1ON
T1GTM

T1GPOL

T1GVAL

CK
R

Acq. Control

Data Bus
D

Q
RD
T1GCON

Interrupt

T1GGO/DONE

Set
TMR1GIF

det
TMR1GE

Set flag bit

TMR1IF on
Overflow

TMR1ON
TMR1(2)

To ADC Auto-Conversion

TMR1H

TMR1L

EN
Q

T1CLK

Synchronized
Clock Input

0
1

TMR1CS<1:0>
SOSCO/T1CKI

Secondary
Oscillator
SOSCI

T1SYNC

OUT
LFINTOSC

Synchronize(3)

Prescaler
1, 2, 4, 8

det

EN
0

T1OSCEN
(1)

FOSC
Internal
Clock

FOSC/4
Internal
Clock

2
T1CKPS<1:0>
FOSC/2
Internal
Clock

Sleep input

To Clock Switching
Modules

Note 1: ST Buffer is high speed type when using T1CKI.

2: Timer1 register increments on rising edge.
3: Synchronize does not operate while in Sleep.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 167

PIC16(L)F1508/9
19.1

Timer1 Operation

19.2

The Timer1 module is a 16-bit incrementing counter

which is accessed through the TMR1H:TMR1L register
pair. Writes to TMR1H or TMR1L directly update the
counter.
When used with an internal clock source, the module is
a timer and increments on every instruction cycle.
When used with an external clock source, the module
can be used as either a timer or counter and increments on every selected edge of the external source.
Timer1 is enabled by configuring the TMR1ON and
TMR1GE bits in the T1CON and T1GCON registers,
respectively. Table 19-1 displays the Timer1 enable
selections.

TABLE 19-1:

TIMER1 ENABLE
SELECTIONS

Clock Source Selection

The TMR1CS<1:0> bits of the T1CON register are used

to select the clock source for Timer1. Table 19-2
displays the clock source selections.

19.2.1

INTERNAL CLOCK SOURCE

When the internal clock source is selected the

TMR1H:TMR1L register pair will increment on multiples
of FOSC as determined by the Timer1 prescaler.
When the FOSC internal clock source is selected, the
Timer1 register value will increment by four counts every
instruction clock cycle. Due to this condition, a 2 LSB
error in resolution will occur when reading the Timer1
value. To utilize the full resolution of Timer1, an
asynchronous input signal must be used to gate the
Timer1 clock input.
The following asynchronous sources may be used:
Asynchronous event on the T1G pin to Timer1
gate

Timer1
Operation

TMR1ON

TMR1GE

Off

19.2.2

Off

Always On

When the external clock source is selected, the Timer1

module may work as a timer or a counter.

Count Enabled

EXTERNAL CLOCK SOURCE

When enabled to count, Timer1 is incremented on the

rising edge of the external clock input T1CKI. The
external clock source can be synchronized to the
microcontroller system clock or it can run
asynchronously.

Note:

In Counter mode, a falling edge must be

registered by the counter prior to the first
incrementing rising edge after any one or
more of the following conditions:

TABLE 19-2:

Timer1 enabled after POR

Write to TMR1H or TMR1L
Timer1 is disabled
Timer1 is disabled (TMR1ON = 0)
when T1CKI is high then Timer1 is
enabled (TMR1ON=1) when T1CKI is
low.

CLOCK SOURCE SELECTIONS

TMR1CS<1:0>

T1OSCEN

LFINTOSC

Secondary Oscillator Circuit on SOSCI/SOSCO Pins

Clock Source

External Clocking on T1CKI Pin

System Clock (FOSC) or Oscillator. Circuit on SOSCI/SOSCO

Instruction Clock (FOSC/4)

DS41609A-page 168

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
19.3

Timer1 Prescaler

Timer1 has four prescaler options allowing 1, 2, 4 or 8

divisions of the clock input. The T1CKPS bits of the
T1CON register control the prescale counter. The
prescale counter is not directly readable or writable;
however, the prescaler counter is cleared upon a write to
TMR1H or TMR1L.

19.4

Timer1 Operation in
Asynchronous Counter Mode

If control bit T1SYNC of the T1CON register is set, the

external clock input is not synchronized. The timer
increments asynchronously to the internal phase
clocks. If the external clock source is selected then the
timer will continue to run during Sleep and can
generate an interrupt on overflow, which will wake-up
the processor. However, special precautions in
software are needed to read/write the timer (see
Section 19.4.1 Reading and Writing Timer1 in
Asynchronous Counter Mode).
Note:

19.4.1

When switching from synchronous to

asynchronous operation, it is possible to
skip an increment. When switching from
asynchronous to synchronous operation,
it is possible to produce an additional
increment.

When Timer1 Gate Enable mode is enabled, Timer1

will increment on the rising edge of the Timer1 clock
source. When Timer1 Gate Enable mode is disabled,
no incrementing will occur and Timer1 will hold the
current count. See Figure 19-3 for timing details.

TABLE 19-3:

TIMER1 GATE ENABLE

SELECTIONS

T1CLK

T1GPOL

T1G

Counts

Holds Count

Counts

19.5.2

Timer1 Operation

TIMER1 GATE SOURCE

SELECTION

Timer1 gate source selections are shown in Table 19-4.

Source selection is controlled by the T1GSS<1:0> bits
of the T1GCON register. The polarity for each available
source is also selectable. Polarity selection is controlled
by the T1GPOL bit of the T1GCON register.

TABLE 19-4:
T1GSS

READING AND WRITING TIMER1 IN

ASYNCHRONOUS COUNTER
MODE

Reading TMR1H or TMR1L while the timer is running

from an external asynchronous clock will ensure a valid
read (taken care of in hardware). However, the user
should keep in mind that reading the 16-bit timer in two
8-bit values itself, poses certain problems, since the
timer may overflow between the reads.

TIMER1 GATE SOURCES

Timer1 Gate Source

Timer1 Gate Pin

Overflow of Timer0
(TMR0 increments from FFh to 00h)

Comparator 1 Output SYNCC1OUT

(optionally synchronized comparator output)

Comparator 2 Output SYNCC2OUT

(optionally synchronized comparator output)

For writes, it is recommended that the user simply stop

the timer and write the desired values. A write
contention may occur by writing to the timer registers,
while the register is incrementing. This may produce an
unpredictable value in the TMR1H:TMR1L register pair.

19.5

Timer1 Gate

Timer1 can be configured to count freely or the count

can be enabled and disabled using Timer1 gate
circuitry. This is also referred to as Timer1 Gate Enable.
Timer1 gate can also be driven by multiple selectable
sources.

19.5.1

TIMER1 GATE ENABLE

The Timer1 Gate Enable mode is enabled by setting

the TMR1GE bit of the T1GCON register. The polarity
of the Timer1 Gate Enable mode is configured using
the T1GPOL bit of the T1GCON register.

2011 Microchip Technology Inc.

Preliminary

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PIC16(L)F1508/9
19.5.2.1

T1G Pin Gate Operation

19.5.5

The T1G pin is one source for Timer1 Gate Control. It

can be used to supply an external source to the Timer1
gate circuitry.

19.5.2.2

Timer0 Overflow Gate Operation

When Timer0 increments from FFh to 00h, a low-tohigh pulse will automatically be generated and internally supplied to the Timer1 gate circuitry.

19.5.3

TIMER1 GATE TOGGLE MODE

When Timer1 Gate Toggle mode is enabled, it is possible to measure the full-cycle length of a Timer1 gate
signal, as opposed to the duration of a single level
pulse.
The Timer1 gate source is routed through a flip-flop that
changes state on every incrementing edge of the signal. See Figure 19-4 for timing details.

TIMER1 GATE VALUE STATUS

When Timer1 Gate Value Status is utilized, it is possible

to read the most current level of the gate control value.
The value is stored in the T1GVAL bit in the T1GCON
register. The T1GVAL bit is valid even when the Timer1
gate is not enabled (TMR1GE bit is cleared).

19.5.6

TIMER1 GATE EVENT INTERRUPT

When Timer1 Gate Event Interrupt is enabled, it is possible to generate an interrupt upon the completion of a
gate event. When the falling edge of T1GVAL occurs,
the TMR1GIF flag bit in the PIR1 register will be set. If
the TMR1GIE bit in the PIE1 register is set, then an
interrupt will be recognized.
The TMR1GIF flag bit operates even when the Timer1
gate is not enabled (TMR1GE bit is cleared).

Timer1 Gate Toggle mode is enabled by setting the

T1GTM bit of the T1GCON register. When the T1GTM
bit is cleared, the flip-flop is cleared and held clear. This
is necessary in order to control which edge is
measured.
Note:

19.5.4

Enabling Toggle mode at the same time

as changing the gate polarity may result in
indeterminate operation.

TIMER1 GATE SINGLE-PULSE

MODE

When Timer1 Gate Single-Pulse mode is enabled, it is

possible to capture a single pulse gate event. Timer1
Gate Single-Pulse mode is first enabled by setting the
T1GSPM bit in the T1GCON register. Next, the T1GGO/
DONE bit in the T1GCON register must be set. The
Timer1 will be fully enabled on the next incrementing
edge. On the next trailing edge of the pulse, the T1GGO/
DONE bit will automatically be cleared. No other gate
events will be allowed to increment Timer1 until the
T1GGO/DONE bit is once again set in software. See
Figure 19-5 for timing details.
If the Single Pulse Gate mode is disabled by clearing the
T1GSPM bit in the T1GCON register, the T1GGO/DONE
bit should also be cleared.
Enabling the Toggle mode and the Single-Pulse mode
simultaneously will permit both sections to work
together. This allows the cycle times on the Timer1 gate
source to be measured. See Figure 19-6 for timing
details.

DS41609A-page 170

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
19.6

Timer1 Interrupt

19.7.1

The Timer1 register pair (TMR1H:TMR1L) increments

to FFFFh and rolls over to 0000h. When Timer1 rolls
over, the Timer1 interrupt flag bit of the PIR1 register is
set. To enable the interrupt on rollover, you must set
these bits:

TMR1ON bit of the T1CON register

TMR1IE bit of the PIE1 register
PEIE bit of the INTCON register
GIE bit of the INTCON register

ALTERNATE PIN LOCATIONS

This module incorporates I/O pins that can be moved to

other locations with the use of the alternate pin function
register, APFCON. To determine which pins can be
moved and what their default locations are upon a
Reset, see Section 11.1 Alternate Pin Function for
more information.

The interrupt is cleared by clearing the TMR1IF bit in

the Interrupt Service Routine.
The TMR1H:TMR1L register pair and the
TMR1IF bit should be cleared before
enabling interrupts.

Note:

19.7

Timer1 Operation During Sleep

Timer1 can only operate during Sleep when setup in

Asynchronous Counter mode. In this mode, an external
crystal or clock source can be used to increment the
counter. To set up the timer to wake the device:

TMR1ON bit of the T1CON register must be set

TMR1IE bit of the PIE1 register must be set
PEIE bit of the INTCON register must be set
T1SYNC bit of the T1CON register must be set
TMR1CS bits of the T1CON register must be
configured

The device will wake-up on an overflow and execute

the next instructions. If the GIE bit of the INTCON
register is set, the device will call the Interrupt Service
Routine.
Timer1 oscillator will continue to operate in Sleep
regardless of the T1SYNC bit setting.

FIGURE 19-2:

TIMER1 INCREMENTING EDGE

T1CKI = 1
when TMR1
Enabled

T1CKI = 0
when TMR1
Enabled

Note 1:
2:

Arrows indicate counter increments.

In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of the clock.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 171

PIC16(L)F1508/9
FIGURE 19-3:

TIMER1 GATE ENABLE MODE

TMR1GE
T1GPOL
t1g_in

T1CKI

T1GVAL

Timer1

FIGURE 19-4:

N+1

N+2

N+3

N+4

TIMER1 GATE TOGGLE MODE

TMR1GE
T1GPOL

T1GTM

t1g_in

T1CKI

T1GVAL

Timer1

DS41609A-page 172

N+1 N+2 N+3

N+4

Preliminary

N+5 N+6 N+7

N+8

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 19-5:

TIMER1 GATE SINGLE-PULSE MODE

TMR1GE
T1GPOL
T1GSPM
T1GGO/

Cleared by hardware on
falling edge of T1GVAL

Set by software

DONE

Counting enabled on
rising edge of T1G

t1g_in

T1CKI

T1GVAL

Timer1

TMR1GIF

N+1

Set by hardware on
falling edge of T1GVAL

Cleared by software

2011 Microchip Technology Inc.

N+2

Preliminary

Cleared by
software

DS41609A-page 173

PIC16(L)F1508/9
FIGURE 19-6:

TIMER1 GATE SINGLE-PULSE AND TOGGLE COMBINED MODE

TMR1GE
T1GPOL
T1GSPM
T1GTM
T1GGO/

Cleared by hardware on
falling edge of T1GVAL

Set by software

DONE

Counting enabled on
rising edge of T1G

t1g_in

T1CKI

T1GVAL

Timer1

TMR1GIF

DS41609A-page 174

Cleared by software

N+1

N+2

N+3

Set by hardware on
falling edge of T1GVAL

Preliminary

N+4
Cleared by
software

2011 Microchip Technology Inc.

PIC16(L)F1508/9
19.8

Timer1 Control Registers

T1CON: TIMER1 CONTROL REGISTER

R/W-0/u

TMR1CS<1:0>

R/W-0/u

T1CKPS<1:0>

R/W-0/u

U-0

R/W-0/u

T1OSCEN

T1SYNC

TMR1ON

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

TMR1CS<1:0>: Timer1 Clock Source Select bits

11 = Timer1 clock source is Capacitive Sensing Oscillator (CAPOSC)
10 = Timer1 clock source is pin or oscillator:
If T1OSCEN = 0:
External clock from T1CKI pin (on the rising edge)
If T1OSCEN = 1:
Crystal oscillator on SOSCI/SOSCO pins
01 = Timer1 clock source is system clock (FOSC)
00 = Timer1 clock source is instruction clock (FOSC/4)

bit 5-4

T1CKPS<1:0>: Timer1 Input Clock Prescale Select bits

11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value

bit 3

T1OSCEN: LP Oscillator Enable Control bit

1 = Dedicated Timer1 oscillator circuit enabled
0 = Dedicated Timer1 oscillator circuit disabled

bit 2

T1SYNC: Timer1 Synchronization Control bit

1 = Do not synchronize asynchronous clock input
0 = Synchronize asynchronous clock input with system clock (FOSC)

bit 1

Unimplemented: Read as 0

bit 0

TMR1ON: Timer1 On bit

1 = Enables Timer1
0 = Stops Timer1 and clears Timer1 gate flip-flop

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 175

PIC16(L)F1508/9
REGISTER 19-2:

T1GCON: TIMER1 GATE CONTROL REGISTER

R/W-0/u

R/W/HC-0/u

R-x/x

TMR1GE

T1GPOL

T1GTM

T1GSPM

T1GGO/
DONE

T1GVAL

R/W-0/u

T1GSS<1:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

HC = Bit is cleared by hardware

bit 7

TMR1GE: Timer1 Gate Enable bit

If TMR1ON = 0:
This bit is ignored
If TMR1ON = 1:
1 = Timer1 counting is controlled by the Timer1 gate function
0 = Timer1 counts regardless of Timer1 gate function

bit 6

T1GPOL: Timer1 Gate Polarity bit

1 = Timer1 gate is active-high (Timer1 counts when gate is high)
0 = Timer1 gate is active-low (Timer1 counts when gate is low)

bit 5

T1GTM: Timer1 Gate Toggle Mode bit

1 = Timer1 Gate Toggle mode is enabled
0 = Timer1 Gate Toggle mode is disabled and toggle flip-flop is cleared
Timer1 gate flip-flop toggles on every rising edge.

bit 4

T1GSPM: Timer1 Gate Single-Pulse Mode bit

1 = Timer1 gate Single-Pulse mode is enabled and is controlling Timer1 gate
0 = Timer1 gate Single-Pulse mode is disabled

bit 3

T1GGO/DONE: Timer1 Gate Single-Pulse Acquisition Status bit

1 = Timer1 gate single-pulse acquisition is ready, waiting for an edge
0 = Timer1 gate single-pulse acquisition has completed or has not been started

bit 2

T1GVAL: Timer1 Gate Current State bit

Indicates the current state of the Timer1 gate that could be provided to TMR1H:TMR1L.
Unaffected by Timer1 Gate Enable (TMR1GE).

bit 0

T1GSS<1:0>: Timer1 Gate Source Select bits

11 = Comparator 2 optionally synchronized output (SYNCC2OUT)
10 = Comparator 1 optionally synchronized output (SYNCC1OUT)
01 = Timer0 overflow output
00 = Timer1 gate pin

DS41609A-page 176

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 19-5:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH TIMER1

Bit 7

Bit 6

Bit 5

Bit 4

ANSELA

APFCON

INTCON
PIE1
PIR1

Bit 2

ANSA4

ANSA2

ANSA1

ANSA0

115

SSSEL

T1GSEL

CLC1SEL

NCO1SEL

112

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

Holding Register for the Most Significant Byte of the 16-bit TMR1 Count

TMR1L

Holding Register for the Least Significant Byte of the 16-bit TMR1 Count

T1CON
T1GCON

Legend:
*
Note 1:

Bit 0

TMR1GIE

TMR1H
TRISA

Bit 1

Bit 3

TMR1CS<1:0>
TMR1GE

T1GPOL

TRISA5

TRISA4

T1CKPS<1:0>
T1GTM

T1GSPM

82
171*
171*

(1)

TRISA2

TRISA1

TRISA0

114

T1OSCEN

T1SYNC

TMR1ON

175

T1GGO/
DONE

T1GVAL

T1GSS<1:0>

176

= unimplemented location, read as 0. Shaded cells are not used by the Timer1 module.
Page provides register information.
Unimplemented, read as 1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 177

PIC16(L)F1508/9
NOTES:

DS41609A-page 178

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
20.0

TIMER2 MODULE

The Timer2 module incorporates the following features:

8-bit Timer and Period registers (TMR2 and PR2,
respectively)
Readable and writable (both registers)
Software programmable prescaler (1:1, 1:4, 1:16,
and 1:64)
Software programmable postscaler (1:1 to 1:16)
Interrupt on TMR2 match with PR2, respectively
See Figure 20-1 for a block diagram of Timer2.

FIGURE 20-1:

TIMER2 BLOCK DIAGRAM

TMR2
Output

FOSC/4

Prescaler
1:1, 1:4, 1:16, 1:64
2

TMR2
Comparator

Sets Flag
bit TMR2IF

Reset
Postscaler
1:1 to 1:16

T2CKPS<1:0>
4

PR2

T2OUTPS<3:0>

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 179

PIC16(L)F1508/9
20.1

Timer2 Operation

20.3

The clock input to the Timer2 module is the system

instruction clock (FOSC/4).
TMR2 increments from 00h on each clock edge.
A 4-bit counter/prescaler on the clock input allows direct
input, divide-by-4 and divide-by-16 prescale options.
These options are selected by the prescaler control bits,
T2CKPS<1:0> of the T2CON register. The value of
TMR2 is compared to that of the Period register, PR2, on
each clock cycle. When the two values match, the
comparator generates a match signal as the timer
output. This signal also resets the value of TMR2 to 00h
on the next cycle and drives the output counter/
postscaler (see Section 20.2 Timer2 Interrupt).

Timer2 Output

The unscaled output of TMR2 is available primarily to

the PWMx module, where it is used as a time base for
operation.

20.4

Timer2 Operation During Sleep

Timer2 cannot be operated while the processor is in

Sleep mode. The contents of the TMR2 and PR2
registers will remain unchanged while the processor is
in Sleep mode.

The TMR2 and PR2 registers are both directly readable

and writable. The TMR2 register is cleared on any
device Reset, whereas the PR2 register initializes to
FFh. Both the prescaler and postscaler counters are
cleared on the following events:

a write to the TMR2 register

a write to the T2CON register
Power-on Reset (POR)
Brown-out Reset (BOR)
MCLR Reset
Watchdog Timer (WDT) Reset
Stack Overflow Reset
Stack Underflow Reset
RESET Instruction
Note:

20.2

TMR2 is not cleared when T2CON is

written.

Timer2 Interrupt

Timer2 can also generate an optional device interrupt.

The Timer2 output signal (TMR2-to-PR2 match)
provides the input for the 4-bit counter/postscaler. This
counter generates the TMR2 match interrupt flag which
is latched in TMR2IF of the PIR1 register. The interrupt
is enabled by setting the TMR2 Match Interrupt Enable
bit, TMR2IE of the PIE1 register.
A range of 16 postscale options (from 1:1 through 1:16
inclusive) can be selected with the postscaler control
bits, T2OUTPS<3:0>, of the T2CON register.

DS41609A-page 180

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 20-1:
U-0

T2CON: TIMER2 CONTROL REGISTER

R/W-0/0

T2OUTPS<3:0>

R/W-0/0

TMR2ON

bit 7

R/W-0/0

T2CKPS<1:0>
bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

Unimplemented: Read as 0

bit 6-3

T2OUTPS<3:0>: Timer2 Output Postscaler Select bits

0000 = 1:1 Postscaler
0001 = 1:2 Postscaler
0010 = 1:3 Postscaler
0011 = 1:4 Postscaler
0100 = 1:5 Postscaler
0101 = 1:6 Postscaler
0110 = 1:7 Postscaler
0111 = 1:8 Postscaler
1000 = 1:9 Postscaler
1001 = 1:10 Postscaler
1010 = 1:11 Postscaler
1011 = 1:12 Postscaler
1100 = 1:13 Postscaler
1101 = 1:14 Postscaler
1110 = 1:15 Postscaler
1111 = 1:16 Postscaler

bit 2

TMR2ON: Timer2 On bit

1 = Timer2 is on
0 = Timer2 is off

bit 1-0

T2CKPS<1:0>: Timer2 Clock Prescale Select bits

00 = Prescaler is 1
01 = Prescaler is 4
10 = Prescaler is 16
11 = Prescaler is 64

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 181

PIC16(L)F1508/9
TABLE 20-1:
Name
INTCON

SUMMARY OF REGISTERS ASSOCIATED WITH TIMER2

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

PR2

Timer2 Module Period Register

82
179*

PWM1CON

PWM1EN

PWM1OE

PWM1OUT PWM1POL

269

PWM2CON

PWM2EN

PWM2OE

PWM2OUT PWM2POL

269

PWM3CON

PWM3EN

PWM3OE

PWM3OUT PWM3POL

269

PWM4CON

PWM4EN

PWM4OE

PWM4OUT PWM4POL

269

T2CON
TMR2

Legend:
*

T2OUTPS<3:0>

TMR2ON

T2CKPS<1:0>

Holding Register for the 8-bit TMR2 Count

181
179*

= unimplemented location, read as 0. Shaded cells are not used for Timer2 module.
Page provides register information.

DS41609A-page 182

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.0

MASTER SYNCHRONOUS
SERIAL PORT MODULE

21.1

Master SSP (MSSP) Module

Overview

The Master Synchronous Serial Port (MSSPx) module

is a serial interface useful for communicating with other
peripheral or microcontroller devices. These peripheral
devices may be serial EEPROMs, shift registers, display drivers, A/D converters, etc. The MSSPx module
can operate in one of two modes:
Serial Peripheral Interface (SPI)
Inter-Integrated Circuit (I2C)
The SPI interface supports the following modes and
features:

Master mode
Slave mode
Clock Parity
Slave Select Synchronization (Slave mode only)
Daisy-chain connection of slave devices

Figure 21-1 is a block diagram of the SPI interface

module.

FIGURE 21-1:

MSSPX BLOCK DIAGRAM (SPI MODE)

Data Bus
Read

Write
SSPBUF Reg

SDI
SSPSR Reg
SDO

bit 0

SSx Control
Enable

Shift
Clock

2 (CKP, CKE)
Clock Select

Edge
Select
SSPM<3:0>
4
SCK
Edge
Select

TRIS bit

2011 Microchip Technology Inc.

Preliminary

( TMR22Output )
Prescaler TOSC
4, 16, 64
Baud Rate
Generator
(SSPxADD)

DS41609A-page 183

PIC16(L)F1508/9
The I2C interface supports the following modes and
features:
Master mode
Slave mode
Byte NACKing (Slave mode)
Limited Multi-master support
7-bit and 10-bit addressing
Start and Stop interrupts
Interrupt masking
Clock stretching
Bus collision detection
General call address matching
Address masking
Address Hold and Data Hold modes
Selectable SDAx hold times

Note 1: In devices with more than one MSSP

module, it is very important to pay close
attention to SSPxCONx register names.
SSPxCON1 and SSPxCON2 registers
control different operational aspects of
the same module, while SSPxCON1 and
SSP2CON1 control the same features for
two different modules.
2: Throughout this section, generic references to an MSSPx module in any of its
operating modes may be interpreted as
being equally applicable to MSSPx or
MSSP2. Register names, module I/O signals, and bit names may use the generic
designator x to indicate the use of a
numeral to distinguish a particular module
when required.

Figure 21-2 is a block diagram of the I2C interface module in Master mode. Figure 21-3 is a diagram of the I2C
interface module in Slave mode.

MSSPX BLOCK DIAGRAM (I2C MASTER MODE)

Internal
data bus
Read

[SSPM<3:0>]

Write
SSPxBUF

Baud Rate
Generator
(SSPxADD)
Shift
Clock

SDAx
SDAx in

Receive Enable (RCEN)

SCLx

SCLx in
Bus Collision

DS41609A-page 184

LSb

Start bit, Stop bit,

Acknowledge
Generate (SSPxCON2)

Start bit detect,

Stop bit detect
Write collision detect
Clock arbitration
State counter for
end of XMIT/RCV
Address Match detect

Preliminary

Clock Cntl

SSPxSR
MSb

(Hold off clock source)

FIGURE 21-2:

Clock arbitrate/BCOL detect

The PIC16F1508/9 has one MSSP module.

Set/Reset: S, P, SSPxSTAT, WCOL, SSPOV

Reset SEN, PEN (SSPxCON2)
Set SSPxIF, BCLxIF

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 21-3:

MSSP BLOCK DIAGRAM (I2C SLAVE MODE)

Internal
Data Bus
Read

Write
SSPxBUF Reg

SCLx
Shift
Clock

SSPxSR Reg
SDAx

MSb

LSb

SSPxMSK Reg
Match Detect

Addr Match

SSPxADD Reg
Start and
Stop bit Detect

2011 Microchip Technology Inc.

Preliminary

Set, Reset
S, P bits
(SSPxSTAT Reg)

DS41609A-page 185

PIC16(L)F1508/9
21.2

SPI Mode Overview

The Serial Peripheral Interface (SPI) bus is a

synchronous serial data communication bus that
operates in Full-Duplex mode. Devices communicate
in a master/slave environment where the master device
initiates the communication. A slave device is
controlled through a Chip Select known as Slave
Select.
The SPI bus specifies four signal connections:

During each SPI clock cycle, a full-duplex data

transmission occurs. This means that while the master
device is sending out the MSb from its shift register (on
its SDOx pin) and the slave device is reading this bit
and saving it as the LSb of its shift register, that the
slave device is also sending out the MSb from its shift
register (on its SDOx pin) and the master device is
reading this bit and saving it as the LSb of its shift
register.
After 8 bits have been shifted out, the master and slave
have exchanged register values.

Serial Clock (SCKx)

Serial Data Out (SDOx)
Serial Data In (SDIx)
Slave Select (SSx)

If there is more data to exchange, the shift registers are

loaded with new data and the process repeats itself.

Figure 21-1 shows the block diagram of the MSSP

module when operating in SPI mode.
The SPI bus operates with a single master device and
one or more slave devices. When multiple slave
devices are used, an independent Slave Select connection is required from the master device to each
slave device.
Figure 21-4 shows a typical connection between a
master device and multiple slave devices.
The master selects only one slave at a time. Most slave
devices have tri-state outputs so their output signal
appears disconnected from the bus when they are not
selected.
Transmissions involve two shift registers, eight bits in
size, one in the master and one in the slave. With either
the master or the slave device, data is always shifted
out one bit at a time, with the Most Significant bit (MSb)
shifted out first. At the same time, a new Least
Significant bit (LSb) is shifted into the same register.

Whether the data is meaningful or not (dummy data),

depends on the application software. This leads to
three scenarios for data transmission:
Master sends useful data and slave sends dummy
data.
Master sends useful data and slave sends useful
data.
Master sends dummy data and slave sends useful
data.
Transmissions may involve any number of clock
cycles. When there is no more data to be transmitted,
the master stops sending the clock signal and it deselects the slave.
Every slave device connected to the bus that has not
been selected through its slave select line must disregard the clock and transmission signals and must not
transmit out any data of its own.

Figure 21-5 shows a typical connection between two

processors configured as master and slave devices.
Data is shifted out of both shift registers on the programmed clock edge and latched on the opposite edge
of the clock.
The master device transmits information out on its
SDOx output pin which is connected to, and received
by, the slaves SDIx input pin. The slave device transmits information out on its SDOx output pin, which is
connected to, and received by, the masters SDIx input
pin.
To begin communication, the master device first sends
out the clock signal. Both the master and the slave
devices should be configured for the same clock polarity.
The master device starts a transmission by sending out
the MSb from its shift register. The slave device reads
this bit from that same line and saves it into the LSb
position of its shift register.

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Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 21-4:

SPI MASTER AND MULTIPLE SLAVE CONNECTION

SPI Master

SCKx

SDOx
SDIx

SDIx
SDOx

General I/O
General I/O

SSx

General I/O

SCKx
SDIx
SDOx

SPI Slave
#1

SPI Slave
#2

SSx
SCKx
SDIx
SDOx

SPI Slave
#3

SSx

21.2.1

SPI MODE REGISTERS

The MSSP module has five registers for SPI mode

operation. These are:

MSSP STATUS register (SSPxSTAT)

MSSP Control Register 1 (SSPxCON1)
MSSP Control Register 3 (SSPxCON3)
MSSP Data Buffer register (SSPxBUF)
MSSP Address register (SSPxADD)
MSSP Shift register (SSPxSR)
(Not directly accessible)

SSPxCON1 and SSPxSTAT are the control

STATUS registers in SPI mode operation.
SSPxCON1 register is readable and writable.
lower 6 bits of the SSPxSTAT are read-only.
upper two bits of the SSPxSTAT are read/write.

and
The
The
The

In SPI master mode, SSPxADD can be loaded with a

value used in the Baud Rate Generator. More information on the Baud Rate Generator is available in
Section 21.7 Baud Rate Generator.
SSPxSR is the shift register used for shifting data in
and out. SSPxBUF provides indirect access to the
SSPxSR register. SSPxBUF is the buffer register to
which data bytes are written, and from which data
bytes are read.
In receive operations, SSPxSR and SSPxBUF
together create a buffered receiver. When SSPxSR
receives a complete byte, it is transferred to SSPxBUF
and the SSPxIF interrupt is set.
During transmission, the SSPxBUF is not buffered. A
write to SSPxBUF will write to both SSPxBUF and
SSPxSR.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 187

PIC16(L)F1508/9
21.2.2

SPI MODE OPERATION

When initializing the SPI, several options need to be

specified. This is done by programming the appropriate
control bits (SSPxCON1<5:0> and SSPxSTAT<7:6>).
These control bits allow the following to be specified:

Master mode (SCKx is the clock output)

Slave mode (SCKx is the clock input)
Clock Polarity (Idle state of SCKx)
Data Input Sample Phase (middle or end of data
output time)
Clock Edge (output data on rising/falling edge of
SCKx)
Clock Rate (Master mode only)
Slave Select mode (Slave mode only)
To enable the serial port, SSP Enable bit, SSPEN of the
SSPxCON1 register, must be set. To reset or reconfigure SPI mode, clear the SSPEN bit, re-initialize the
SSPxCONx registers and then set the SSPEN bit. This
configures the SDI, SDO, SCK and SS pins as serial
port pins. For the pins to behave as the serial port function, some must have their data direction bits (in the
TRIS register) appropriately programmed as follows:
SDIx must have corresponding TRIS bit set
SDOx must have corresponding TRIS bit cleared
SCKx (Master mode) must have corresponding
TRIS bit cleared
SCKx (Slave mode) must have corresponding
TRIS bit set
SSx must have corresponding TRIS bit set
Any serial port function that is not desired may be
overridden by programming the corresponding data
direction (TRIS) register to the opposite value.

FIGURE 21-5:

The MSSP consists of a transmit/receive shift register

(SSPxSR) and a buffer register (SSPxBUF). The
SSPxSR shifts the data in and out of the device, MSb
first. The SSPxBUF holds the data that was written to
the SSPxSR until the received data is ready. Once the
8 bits of data have been received, that byte is moved to
the SSPxBUF register. Then, the Buffer Full Detect bit,
BF of the SSPxSTAT register, and the interrupt flag bit,
SSPxIF, are set. This double-buffering of the received
data (SSPxBUF) allows the next byte to start reception
before reading the data that was just received. Any
write
to
the
SSPxBUF
register
during
transmission/reception of data will be ignored and the
write collision detect bit, WCOL of the SSPxCON1
register, will be set. User software must clear the
WCOL bit to allow the following write(s) to the
SSPxBUF register to complete successfully.
When the application software is expecting to receive
valid data, the SSPxBUF should be read before the
next byte of data to transfer is written to the SSPxBUF.
The Buffer Full bit, BF of the SSPxSTAT register,
indicates when SSPxBUF has been loaded with the
received data (transmission is complete). When the
SSPxBUF is read, the BF bit is cleared. This data may
be irrelevant if the SPI is only a transmitter. Generally,
the MSSP interrupt is used to determine when the
transmission/reception has completed. If the interrupt
method is not going to be used, then software polling
can be done to ensure that a write collision does not
occur.
The SSPxSR is not directly readable or writable and
can only be accessed by addressing the SSPxBUF
register. Additionally, the SSPxSTAT register indicates
the various Status conditions.

SPI MASTER/SLAVE CONNECTION

SPI Master SSPM<3:0> = 00xx

= 1010

SPI Slave SSPM<3:0> = 010x

SDOx

SDIx

Serial Input Buffer

(BUF)

SDIx

Shift Register
(SSPxSR)
MSb

Serial Input Buffer

(SSPxBUF)

LSb
SCKx
General I/O

Processor 1

DS41609A-page 188

SDOx

Serial Clock
Slave Select
(optional)

Preliminary

Shift Register
(SSPxSR)
MSb

LSb

SCKx
SSx

Processor 2

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.2.3

SPI MASTER MODE

The master can initiate the data transfer at any time

because it controls the SCKx line. The master
determines when the slave (Processor 2, Figure 21-5)
is to broadcast data by the software protocol.
In Master mode, the data is transmitted/received as
soon as the SSPxBUF register is written to. If the SPI
is only going to receive, the SDOx output could be disabled (programmed as an input). The SSPxSR register
will continue to shift in the signal present on the SDIx
pin at the programmed clock rate. As each byte is
received, it will be loaded into the SSPxBUF register as
if a normal received byte (interrupts and Status bits
appropriately set).

The clock polarity is selected by appropriately

programming the CKP bit of the SSPxCON1 register
and the CKE bit of the SSPxSTAT register. This then,
would give waveforms for SPI communication as
shown in Figure 21-6, Figure 21-9 and Figure 21-10,
where the MSb is transmitted first. In Master mode, the
SPI clock rate (bit rate) is user programmable to be one
of the following:

FOSC/4 (or TCY)

FOSC/16 (or 4 * TCY)
FOSC/64 (or 16 * TCY)
Timer2 output/2
Fosc/(4 * (SSPxADD + 1))

Figure 21-6 shows the waveforms for Master mode.

When the CKE bit is set, the SDOx data is valid before
there is a clock edge on SCKx. The change of the input
sample is shown based on the state of the SMP bit. The
time when the SSPxBUF is loaded with the received
data is shown.

FIGURE 21-6:

SPI MODE WAVEFORM (MASTER MODE)

Write to
SSPxBUF
SCKx
(CKP = 0
CKE = 0)
SCKx
(CKP = 1
CKE = 0)

4 Clock
Modes

SCKx
(CKP = 0
CKE = 1)
SCKx
(CKP = 1
CKE = 1)
SDOx
(CKE = 0)

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

SDOx
(CKE = 1)

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

SDIx
(SMP = 0)

bit 0

bit 7

Input
Sample
(SMP = 0)
SDIx
(SMP = 1)

bit 0

bit 7

Input
Sample
(SMP = 1)
SSPxIF
SSPxSR to
SSPxBUF

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 189

PIC16(L)F1508/9
21.2.4

21.2.5

SPI SLAVE MODE

In Slave mode, the data is transmitted and received as

external clock pulses appear on SCKx. When the last
bit is latched, the SSPxIF interrupt flag bit is set.
Before enabling the module in SPI Slave mode, the clock
line must match the proper Idle state. The clock line can
be observed by reading the SCKx pin. The Idle state is
determined by the CKP bit of the SSPxCON1 register.
While in Slave mode, the external clock is supplied by
the external clock source on the SCKx pin. This external clock must meet the minimum high and low times
as specified in the electrical specifications.
While in Sleep mode, the slave can transmit/receive
data. The shift register is clocked from the SCKx pin
input and when a byte is received, the device will generate an interrupt. If enabled, the device will wake-up
from Sleep.
21.2.4.1

Daisy-Chain Configuration

The SPI bus can sometimes be connected in a

daisy-chain configuration. The first slave output is connected to the second slave input, the second slave
output is connected to the third slave input, and so on.
The final slave output is connected to the master input.
Each slave sends out, during a second group of clock
pulses, an exact copy of what was received during the
first group of clock pulses. The whole chain acts as
one large communication shift register. The
daisy-chain feature only requires a single Slave Select
line from the master device.
Figure 21-7 shows the block diagram of a typical
daisy-chain connection when operating in SPI mode.
In a daisy-chain configuration, only the most recent
byte on the bus is required by the slave. Setting the
BOEN bit of the SSPxCON3 register will enable writes
to the SSPxBUF register, even if the previous byte has
not been read. This allows the software to ignore data
that may not apply to it.

SLAVE SELECT
SYNCHRONIZATION

The Slave Select can also be used to synchronize communication. The Slave Select line is held high until the
master device is ready to communicate. When the
Slave Select line is pulled low, the slave knows that a
new transmission is starting.
If the slave fails to receive the communication properly,
it will be reset at the end of the transmission, when the
Slave Select line returns to a high state. The slave is
then ready to receive a new transmission when the
Slave Select line is pulled low again. If the Slave Select
line is not used, there is a risk that the slave will eventually become out of sync with the master. If the slave
misses a bit, it will always be one bit off in future transmissions. Use of the Slave Select line allows the slave
and master to align themselves at the beginning of
each transmission.
The SSx pin allows a Synchronous Slave mode. The
SPI must be in Slave mode with SSx pin control
enabled (SSPxCON1<3:0> = 0100).
When the SSx pin is low, transmission and reception
are enabled and the SDOx pin is driven.
When the SSx pin goes high, the SDOx pin is no longer
driven, even if in the middle of a transmitted byte and
becomes a floating output. External pull-up/pull-down
resistors may be desirable depending on the application.
Note 1: When the SPI is in Slave mode with SSx
pin control enabled (SSPxCON1<3:0> =
0100), the SPI module will reset if the SSx
pin is set to VDD.
2: When the SPI is used in Slave mode with
CKE set; the user must enable SSx pin
control.
3: While operated in SPI Slave mode the
SMP bit of the SSPxSTAT register must
remain clear.

When the SPI module resets, the bit counter is forced

to 0. This can be done by either forcing the SSx pin to
a high level or clearing the SSPEN bit.

DS41609A-page 190

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 21-7:

SPI DAISY-CHAIN CONNECTION

SPI Master

SCK

SDOx
SDIx

SDIx
SDOx

General I/O

SPI Slave
#1

SSx
SCK
SDIx
SDOx

SPI Slave
#2

SSx
SCK
SDIx
SDOx

SPI Slave
#3

SSx

FIGURE 21-8:

SLAVE SELECT SYNCHRONOUS WAVEFORM

SSx
SCKx
(CKP = 0
CKE = 0)
SCKx
(CKP = 1
CKE = 0)
Write to
SSPxBUF

Shift register SSPxSR

and bit count are reset

SSPxBUF to
SSPxSR

SDOx

bit 7

bit 6

bit 7

SDIx

bit 6

bit 0

bit 0
bit 7

bit 7

Input
Sample
SSPxIF
Interrupt
Flag
SSPxSR to
SSPxBUF

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 191

PIC16(L)F1508/9
FIGURE 21-9:

SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 0)

SSx
Optional
SCKx
(CKP = 0
CKE = 0)
SCKx
(CKP = 1
CKE = 0)
Write to
SSPxBUF
Valid
SDOx

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

SDIx
bit 0

bit 7
Input
Sample
SSPxIF
Interrupt
Flag
SSPxSR to
SSPxBUF
Write Collision
detection active

FIGURE 21-10:

SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 1)

SSx
Not Optional
SCKx
(CKP = 0
CKE = 1)
SCKx
(CKP = 1
CKE = 1)
Write to
SSPxBUF
Valid
SDOx

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

SDIx
bit 0

bit 7
Input
Sample

SSPxIF
Interrupt
Flag
SSPxSR to
SSPxBUF
Write Collision
detection active

DS41609A-page 192

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.2.6

SPI OPERATION IN SLEEP MODE

In SPI Master mode, module clocks may be operating

at a different speed than when in Full-Power mode; in
the case of the Sleep mode, all clocks are halted.
Special care must be taken by the user when the MSSP
clock is much faster than the system clock.
In Slave mode, when MSSP interrupts are enabled,
after the master completes sending data, an MSSP
interrupt will wake the controller from Sleep.
If an exit from Sleep mode is not desired, MSSP interrupts should be disabled.
In SPI Master mode, when the Sleep mode is selected,
all module clocks are halted and the transmission/reception will remain in that state until the device
wakes. After the device returns to Run mode, the module will resume transmitting and receiving data.
In SPI Slave mode, the SPI Transmit/Receive Shift
register operates asynchronously to the device. This
allows the device to be placed in Sleep mode and data
to be shifted into the SPI Transmit/Receive Shift
register. When all 8 bits have been received, the MSSP
interrupt flag bit will be set and if enabled, will wake the
device.

TABLE 21-1:
Name
ANSELA
INTCON
PIE1
PIR1
SSP1BUF

SUMMARY OF REGISTERS ASSOCIATED WITH SPI OPERATION

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ANSA4

ANSA2

ANSA1

ANSA0

115

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

Synchronous Serial Port Receive Buffer/Transmit Register

SSP1CON1

WCOL

SSPOV

SSPEN

CKP

SSP1CON3

ACKTIM

PCIE

SCIE

BOEN

SSP1STAT

SMP

CKE

D/A

R/W

TRISA5

TRISA4

(1)

TRISA2

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISA
TRISC

Legend:
*
Note 1:

82
187*

SSPM<3:0>
SDAHT

SBCDE

AHEN

232
DHEN

234

231

TRISA1

TRISA0

114

TRISC0

122

= Unimplemented location, read as 0. Shaded cells are not used by the MSSP in SPI mode.
Page provides register information.
Unimplemented, read as 1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 193

PIC16(L)F1508/9
21.3

I2C MODE OVERVIEW

FIGURE 21-11:

The Inter-Integrated Circuit Bus (I2C) is a multi-master

serial data communication bus. Devices communicate
in a master/slave environment where the master
devices initiate the communication. A Slave device is
controlled through addressing.

VDD
SCLx

The I2C bus specifies two signal connections:

Serial Clock (SCLx)
Serial Data (SDAx)

Figure 21-11 shows a typical connection between two

processors configured as master and slave devices.
The I2C bus can operate with one or more master
devices and one or more slave devices.
There are four potential modes of operation for a given
device:
Master Transmit mode
(master is transmitting data to a slave)
Master Receive mode
(master is receiving data from a slave)
Slave Transmit mode
(slave is transmitting data to a master)
Slave Receive mode
(slave is receiving data from the master)

SDAx

The Acknowledge bit (ACK) is an active-low signal,

which holds the SDAx line low to indicate to the transmitter that the slave device has received the transmitted data and is ready to receive more.
The transition of a data bits is always performed while
the SCLx line is held low. Transitions that occur while
the SCLx line is held high are used to indicate Start and
Stop bits.
If the master intends to write to the slave, then it repeatedly sends out a byte of data, with the slave responding
after each byte with an ACK bit. In this example, the
master device is in Master Transmit mode and the
slave is in Slave Receive mode.
If the master intends to read from the slave, then it
repeatedly receives a byte of data from the slave, and
responds after each byte with an ACK bit. In this example, the master device is in Master Receive mode and
the slave is Slave Transmit mode.

To begin communication, a master device starts out in

Master Transmit mode. The master device sends out a
Start bit followed by the address byte of the slave it
intends to communicate with. This is followed by a single Read/Write bit, which determines whether the master intends to transmit to or receive data from the slave
device.
If the requested slave exists on the bus, it will respond
with an Acknowledge bit, otherwise known as an ACK.
The master then continues in either Transmit mode or
Receive mode and the slave continues in the complement, either in Receive mode or Transmit mode,
respectively.
A Start bit is indicated by a high-to-low transition of the
SDAx line while the SCLx line is held high. Address and
data bytes are sent out, Most Significant bit (MSb) first.
The Read/Write bit is sent out as a logical one when the
master intends to read data from the slave, and is sent
out as a logical zero when it intends to write data to the
slave.

DS41609A-page 194

Slave

SDAx

Figure 21-2 and Figure 21-3 show the block diagrams

of the MSSP module when operating in I2C mode.

SCLx
VDD

Master

Both the SCLx and SDAx connections are bidirectional

open-drain lines, each requiring pull-up resistors for the
supply voltage. Pulling the line to ground is considered
a logical zero and letting the line float is considered a
logical one.

I2C MASTER/
SLAVE CONNECTION

On the last byte of data communicated, the master

device may end the transmission by sending a Stop bit.
If the master device is in Receive mode, it sends the
Stop bit in place of the last ACK bit. A Stop bit is indicated by a low-to-high transition of the SDAx line while
the SCLx line is held high.
In some cases, the master may want to maintain control of the bus and re-initiate another transmission. If
so, the master device may send another Start bit in
place of the Stop bit or last ACK bit when it is in receive
mode.
The I2C bus specifies three message protocols;
Single message where a master writes data to a
slave.
Single message where a master reads data from
a slave.
Combined message where a master initiates a
minimum of two writes, or two reads, or a
combination of writes and reads, to one or more
slaves.

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
When one device is transmitting a logical one, or letting
the line float, and a second device is transmitting a logical zero, or holding the line low, the first device can
detect that the line is not a logical one. This detection,
when used on the SCLx line, is called clock stretching.
Clock stretching gives slave devices a mechanism to
control the flow of data. When this detection is used on
the SDAx line, it is called arbitration. Arbitration
ensures that there is only one master device communicating at any single time.

21.3.1

CLOCK STRETCHING

When a slave device has not completed processing

data, it can delay the transfer of more data through the
process of clock stretching. An addressed slave device
may hold the SCLx clock line low after receiving or
sending a bit, indicating that it is not yet ready to continue. The master that is communicating with the slave
will attempt to raise the SCLx line in order to transfer
the next bit, but will detect that the clock line has not yet
been released. Because the SCLx connection is
open-drain, the slave has the ability to hold that line low
until it is ready to continue communicating.
Clock stretching allows receivers that cannot keep up
with a transmitter to control the flow of incoming data.

21.3.2

ARBITRATION

Each master device must monitor the bus for Start and
Stop bits. If the device detects that the bus is busy, it
cannot begin a new message until the bus returns to an
Idle state.
However, two master devices may try to initiate a transmission on or about the same time. When this occurs,
the process of arbitration begins. Each transmitter
checks the level of the SDAx data line and compares it
to the level that it expects to find. The first transmitter to
observe that the two levels do not match, loses arbitration, and must stop transmitting on the SDAx line.
For example, if one transmitter holds the SDAx line to
a logical one (lets it float) and a second transmitter
holds it to a logical zero (pulls it low), the result is that
the SDAx line will be low. The first transmitter then
observes that the level of the line is different than
expected and concludes that another transmitter is
communicating.
The first transmitter to notice this difference is the one
that loses arbitration and must stop driving the SDAx
line. If this transmitter is also a master device, it also
must stop driving the SCLx line. It then can monitor the
lines for a Stop condition before trying to reissue its
transmission. In the meantime, the other device that
has not noticed any difference between the expected
and actual levels on the SDAx line continues with its
original transmission. It can do so without any complications, because so far, the transmission appears
exactly as expected with no other transmitter disturbing
the message.
Slave Transmit mode can also be arbitrated, when a
master addresses multiple slaves, but this is less common.
If two master devices are sending a message to two different slave devices at the address stage, the master
sending the lower slave address always wins arbitration. When two master devices send messages to the
same slave address, and addresses can sometimes
refer to multiple slaves, the arbitration process must
continue into the data stage.
Arbitration usually occurs very rarely, but it is a necessary process for proper multi-master support.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 195

PIC16(L)F1508/9
21.4

I2C MODE OPERATION

TABLE 21-2:

All MSSP I2C communication is byte oriented and

shifted out MSb first. Six SFR registers and 2 interrupt
flags interface the module with the PIC microcontroller and user software. Two pins, SDAx and SCLx,
are exercised by the module to communicate with
other external I2C devices.
21.4.1

BYTE FORMAT

All communication in I2C is done in 9-bit segments. A

byte is sent from a master to a slave or vice-versa, followed by an Acknowledge bit sent back. After the 8th
falling edge of the SCLx line, the device outputting
data on the SDAx changes that pin to an input and
reads in an acknowledge value on the next clock
pulse.
The clock signal, SCLx, is provided by the master.
Data is valid to change while the SCLx signal is low,
and sampled on the rising edge of the clock. Changes
on the SDAx line while the SCLx line is high define
special conditions on the bus, explained below.
21.4.2

DEFINITION OF I2C TERMINOLOGY

There is language and terminology in the description

of I2C communication that have definitions specific to
I2C. That word usage is defined below and may be
used in the rest of this document without explanation.
This table was adapted from the Philips I2C
specification.
21.4.3

SDAX AND SCLX PINS

Selection of any I2C mode with the SSPEN bit set,

forces the SCLx and SDAx pins to be open-drain.
These pins should be set by the user to inputs by setting the appropriate TRIS bits.
Note: Data is tied to output zero when an I2C
mode is enabled.

21.4.4

SDAX HOLD TIME

The hold time of the SDAx pin is selected by the

SDAHT bit of the SSPxCON3 register. Hold time is the
time SDAx is held valid after the falling edge of SCLx.
Setting the SDAHT bit selects a longer 300 ns minimum hold time and may help on buses with large
capacitance.

DS41609A-page 196

TERM

I2C BUS TERMS

Description

Transmitter

The device which shifts data out

onto the bus.
Receiver
The device which shifts data in
from the bus.
Master
The device that initiates a transfer,
generates clock signals and terminates a transfer.
Slave
The device addressed by the master.
Multi-master
A bus with more than one device
that can initiate data transfers.
Arbitration
Procedure to ensure that only one
master at a time controls the bus.
Winning arbitration ensures that
the message is not corrupted.
Synchronization Procedure to synchronize the
clocks of two or more devices on
the bus.
Idle
No master is controlling the bus,
and both SDAx and SCLx lines are
high.
Active
Any time one or more master
devices are controlling the bus.
Addressed
Slave device that has received a
Slave
matching address and is actively
being clocked by a master.
Matching
Address byte that is clocked into a
Address
slave that matches the value
stored in SSPxADD.
Write Request
Slave receives a matching
address with R/W bit clear, and is
ready to clock in data.
Read Request
Master sends an address byte with
the R/W bit set, indicating that it
wishes to clock data out of the
Slave. This data is the next and all
following bytes until a Restart or
Stop.
Clock Stretching When a device on the bus hold
SCLx low to stall communication.
Bus Collision
Any time the SDAx line is sampled
low by the module while it is outputting and expected high state.

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.4.5

START CONDITION

21.4.7

The I2C specification defines a Start condition as a

transition of SDAx from a high to a low state while
SCLx line is high. A Start condition is always generated by the master and signifies the transition of the
bus from an Idle to an Active state. Figure 21-12
shows wave forms for Start and Stop conditions.

A Restart is valid any time that a Stop would be valid.

A master can issue a Restart if it wishes to hold the
bus after terminating the current transfer. A Restart
has the same effect on the slave that a Start would,
resetting all slave logic and preparing it to clock in an
address. The master may want to address the same or
another slave.

A bus collision can occur on a Start condition if the

module samples the SDAx line low before asserting it
low. This does not conform to the I2C Specification that
states no bus collision can occur on a Start.
21.4.6

RESTART CONDITION

In 10-bit Addressing Slave mode a Restart is required

for the master to clock data out of the addressed
slave. Once a slave has been fully addressed, matching both high and low address bytes, the master can
issue a Restart and the high address byte with the
R/W bit set. The slave logic will then hold the clock
and prepare to clock out data.

STOP CONDITION

A Stop condition is a transition of the SDAx line from

low-to-high state while the SCLx line is high.

After a full match with R/W clear in 10-bit mode, a prior

match flag is set and maintained. Until a Stop condition, a high address with R/W clear, or high address
match fails.

Note: At least one SCLx low time must appear

before a Stop is valid, therefore, if the SDAx
line goes low then high again while the SCLx
line stays high, only the Start condition is
detected.

21.4.8

START/STOP CONDITION INTERRUPT

MASKING

The SCIE and PCIE bits of the SSPxCON3 register

can enable the generation of an interrupt in Slave
modes that do not typically support this function. Slave
modes where interrupt on Start and Stop detect are
already enabled, these bits will have no effect.

FIGURE 21-12:

I2C START AND STOP CONDITIONS

SDAx

SCLx
S

Start

P
Change of

Change of

Data Allowed

Condition

FIGURE 21-13:

Stop
Condition

I2C RESTART CONDITION

Sr
Change of

Change of
Data Allowed

Restart

Data Allowed

Condition

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 197

PIC16(L)F1508/9
21.4.9

21.5.1.1

ACKNOWLEDGE SEQUENCE

I2C Slave 7-bit Addressing Mode

The 9th SCLx pulse for any transferred byte in I2C is

dedicated as an Acknowledge. It allows receiving
devices to respond back to the transmitter by pulling
the SDAx line low. The transmitter must release control of the line during this time to shift in the response.
The Acknowledge (ACK) is an active-low signal, pulling the SDAx line low indicated to the transmitter that
the device has received the transmitted data and is
ready to receive more.

In 7-bit Addressing mode, the LSb of the received data

byte is ignored when determining if there is an address
match.

The result of an ACK is placed in the ACKSTAT bit of

the SSPxCON2 register.

After the acknowledge of the high byte the UA bit is set

and SCLx is held low until the user updates SSPxADD
with the low address. The low address byte is clocked
in and all 8 bits are compared to the low address value
in SSPxADD. Even if there is not an address match;
SSPxIF and UA are set, and SCLx is held low until
SSPxADD is updated to receive a high byte again.
When SSPxADD is updated the UA bit is cleared. This
ensures the module is ready to receive the high
address byte on the next communication.

Slave software, when the AHEN and DHEN bits are

set, allow the user to set the ACK value sent back to
the transmitter. The ACKDT bit of the SSPxCON2 register is set/cleared to determine the response.
Slave hardware will generate an ACK response if the
AHEN and DHEN bits of the SSPxCON3 register are
clear.
There are certain conditions where an ACK will not be
sent by the slave. If the BF bit of the SSPxSTAT register or the SSPOV bit of the SSPxCON1 register are
set when a byte is received.
When the module is addressed, after the 8th falling
edge of SCLx on the bus, the ACKTIM bit of the
SSPxCON3 register is set. The ACKTIM bit indicates
the acknowledge time of the active bus. The ACKTIM
Status bit is only active when the AHEN bit or DHEN
bit is enabled.

21.5

I2C

Slave Mode Operation

The MSSP Slave mode operates in one of four modes

selected in the SSPM bits of SSPxCON1 register. The
modes can be divided into 7-bit and 10-bit Addressing
mode. 10-bit Addressing modes operate the same as
7-bit with some additional overhead for handling the
larger addresses.
Modes with Start and Stop bit interrupts operate the
same as the other modes with SSPxIF additionally
getting set upon detection of a Start, Restart, or Stop
condition.
21.5.1

SLAVE MODE ADDRESSES

The SSPxADD register (Register 21-6) contains the

Slave mode address. The first byte received after a
Start or Restart condition is compared against the
value stored in this register. If the byte matches the
value is loaded into the SSPxBUF register and an
interrupt is generated. If the value does not match, the
module goes idle and no indication is given to the software that anything happened.

21.5.1.2

I2C Slave 10-bit Addressing Mode

In 10-bit Addressing mode, the first received byte is

compared to the binary value of 1 1 1 1 0 A9 A8 0. A9
and A8 are the two MSb of the 10-bit address and
stored in bits 2 and 1 of the SSPxADD register.

A high and low address match as a write request is

required at the start of all 10-bit addressing communication. A transmission can be initiated by issuing a
Restart once the slave is addressed, and clocking in
the high address with the R/W bit set. The slave hardware will then acknowledge the read request and prepare to clock out data. This is only valid for a slave
after it has received a complete high and low address
byte match.
21.5.2

SLAVE RECEPTION

When the R/W bit of a matching received address byte

is clear, the R/W bit of the SSPxSTAT register is
cleared. The received address is loaded into the
SSPxBUF register and acknowledged.
When the overflow condition exists for a received
address, then not Acknowledge is given. An overflow
condition is defined as either bit BF of the SSPxSTAT
register is set, or bit SSPOV of the SSPxCON1 register
is set. The BOEN bit of the SSPxCON3 register modifies this operation. For more information see
Register 21-4.
An MSSP interrupt is generated for each transferred
data byte. Flag bit, SSPxIF, must be cleared by software.
When the SEN bit of the SSPxCON2 register is set,
SCLx will be held low (clock stretch) following each
received byte. The clock must be released by setting
the CKP bit of the SSPxCON1 register, except
sometimes in 10-bit mode. See Section 21.2.3 SPI
Master Mode for more detail.

The SSP Mask register (Register 21-5) affects the

address matching process. See Section 21.5.9
SSPx Mask Register for more information.

DS41609A-page 198

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.5.2.1

7-bit Addressing Reception

21.5.2.2

This section describes a standard sequence of events

for the MSSP module configured as an I2C Slave in
7-bit Addressing mode. Figure 21-14 and Figure 21-15
are used as visual references for this description.
This is a step by step process of what typically must
be done to accomplish I2C communication.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

Start bit detected.

S bit of SSPxSTAT is set; SSPxIF is set if interrupt on Start detect is enabled.
Matching address with R/W bit clear is received.
The slave pulls SDAx low sending an ACK to the
master, and sets SSPxIF bit.
Software clears the SSPxIF bit.
Software reads received address from
SSPxBUF clearing the BF flag.
If SEN = 1; Slave software sets CKP bit to
release the SCLx line.
The master clocks out a data byte.
Slave drives SDAx low sending an ACK to the
master, and sets SSPxIF bit.
Software clears SSPxIF.
Software reads the received byte from
SSPxBUF clearing BF.
Steps 8-12 are repeated for all received bytes
from the Master.
Master sends Stop condition, setting P bit of
SSPxSTAT, and the bus goes idle.

7-bit Reception with AHEN and DHEN

Slave device reception with AHEN and DHEN set

operate the same as without these options with extra
interrupts and clock stretching added after the 8th falling edge of SCLx. These additional interrupts allow the
slave software to decide whether it wants to ACK the
receive address or data byte, rather than the hardware. This functionality adds support for PMBus that
was not present on previous versions of this module.
This list describes the steps that need to be taken by
slave software to use these options for I2C communcation. Figure 21-16 displays a module using both
address and data holding. Figure 21-17 includes the
operation with the SEN bit of the SSPxCON2 register
set.
1.

S bit of SSPxSTAT is set; SSPxIF is set if interrupt on Start detect is enabled.

2. Matching address with R/W bit clear is clocked
in. SSPxIF is set and CKP cleared after the 8th
falling edge of SCLx.
3. Slave clears the SSPxIF.
4. Slave can look at the ACKTIM bit of the
SSPxCON3 register to determine if the SSPxIF
was after or before the ACK.
5. Slave reads the address value from SSPxBUF,
clearing the BF flag.
6. Slave sets ACK value clocked out to the master
by setting ACKDT.
7. Slave releases the clock by setting CKP.
8. SSPxIF is set after an ACK, not after a NACK.
9. If SEN = 1 the slave hardware will stretch the
clock after the ACK.
10. Slave clears SSPxIF.
Note: SSPxIF is still set after the 9th falling edge of
SCLx even if there is no clock stretching and
BF has been cleared. Only if NACK is sent
to master is SSPxIF not set

11. SSPxIF set and CKP cleared after 8th falling

edge of SCLx for a received data byte.
12. Slave looks at ACKTIM bit of SSPxCON3 to
determine the source of the interrupt.
13. Slave reads the received data from SSPxBUF
clearing BF.
14. Steps 7-14 are the same for each received data
byte.
15. Communication is ended by either the slave
sending an ACK = 1, or the master sending a
Stop condition. If a Stop is sent and Interrupt on
Stop Detect is disabled, the slave will only know
by polling the P bit of the SSPSTAT register.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 199

SDAx

SCLx
S

Receiving Data

ACK

Receiving Data

D0 ACK D7

ACK = 1

Preliminary

SSPxIF
Cleared by software

Cleared by software

BF
SSPxBUF is read

First byte
of data is
available
in SSPxBUF

SSPOV

2011 Microchip Technology Inc.

SSPOV set because

SSPxBUF is still full.
ACK is not sent.

SSPxIF set on 9th

falling edge of
SCLx

I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 0, DHEN = 0)

From Slave to Master

Receiving Address

PIC16(L)F1508/9

FIGURE 21-14:

DS41609A-page 200
Bus Master sends
Stop condition

SDAx

SCLx

Receive Data

R/W=0 ACK

SEN

Receive Data

ACK

SEN

ACK

Clock is held low until CKP is set to 1

Preliminary

SSPxIF
Cleared by software
BF
SSPxBUF is read

Cleared by software

SSPxIF set on 9th

falling edge of SCLx

First byte
of data is
available
in SSPxBUF

SSPOV set because

SSPxBUF is still full.
ACK is not sent.
CKP

CKP is written to 1 in software,

releasing SCLx

CKP is written to 1 in software,

releasing SCLx

DS41609A-page 201

SCLx is not held

low because
ACK= 1

PIC16(L)F1508/9

SSPOV

I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 0, DHEN = 0)

Receive Address

FIGURE 21-15:

2011 Microchip Technology Inc.

Bus Master sends

Stop condition

Receiving Data

ACK D7 D6 D5 D4 D3 D2 D1 D0

A7 A6 A5 A4 A3 A2 A1

Received Data

ACK

ACK=1

D7 D6 D5 D4 D3 D2 D1 D0

SSPxIF
If AHEN = 1:
SSPxIF is set
BF

Preliminary

ACKDT

SSPxIF is set on
9th falling edge of
SCLx, after ACK

Address is
read from
SSBUF

Data is read from SSPxBUF

Slave software
clears ACKDT to
CKP

Slave software
sets ACKDT to
not ACK

ACK the received

byte
When AHEN=1:
CKP is cleared by hardware
and SCLx is stretched

No interrupt
after not ACK
from Slave

Cleared by software

When DHEN=1:
CKP is cleared by
hardware on 8th falling
edge of SCLx

CKP set by software,

SCLx is released

ACKTIM
ACKTIM set by hardware
on 8th falling edge of SCLx

2011 Microchip Technology Inc.

S
P

ACKTIM cleared by
hardware in 9th
rising edge of SCLx

ACKTIM set by hardware

on 8th falling edge of SCLx

I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 1, DHEN = 1)

SCLx

PIC16(L)F1508/9

Receiving Address

SDAx

FIGURE 21-16:

DS41609A-page 202

Master sends
Stop condition

Master Releases SDAx

to slave for ACK sequence

ACK

SCLx
S

2 3

6 7

Receive Data

2 3

6 7

ACK

Receive Data

D7 D6 D5 D4 D3 D2 D1 D0

ACK

D7 D6 D5 D4 D3 D2 D1 D0

3 4

6 7

SSPxIF
No interrupt after
if not ACK
from Slave

Cleared by software

Preliminary

Received
address is loaded into
SSPxBUF

Received data is
available on SSPxBUF

ACKDT
Slave software clears
ACKDT to ACK
the received byte

SSPxBUF can be
read any time before
next byte is loaded

Slave sends
not ACK

CKP
When DHEN = 1;
on the 8th falling edge
of SCLx of a received
data byte, CKP is cleared

ACKTIM
ACKTIM is set by hardware
on 8th falling edge of SCLx
S

DS41609A-page 203

ACKTIM is cleared by hardware

on 9th rising edge of SCLx

Set by software,
release SCLx

CKP is not cleared

if not ACK

PIC16(L)F1508/9

When AHEN = 1;
on the 8th falling edge
of SCLx of an address
byte, CKP is cleared

I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 1, DHEN = 1)

Receiving Address
A7 A6 A5 A4 A3 A2 A1

FIGURE 21-17:

2011 Microchip Technology Inc.

R/W = 0
SDAx

Master sends
Stop condition

Master releases
SDAx to slave for ACK sequence

PIC16(L)F1508/9
21.5.3

SLAVE TRANSMISSION

21.5.3.2

7-bit Transmission

When the R/W bit of the incoming address byte is set

and an address match occurs, the R/W bit of the
SSPxSTAT register is set. The received address is
loaded into the SSPxBUF register, and an ACK pulse is
sent by the slave on the ninth bit.

A master device can transmit a read request to a

slave, and then clock data out of the slave. The list
below outlines what software for a slave will need to
do to accomplish a standard transmission.
Figure 21-17 can be used as a reference to this list.

Following the ACK, slave hardware clears the CKP bit

and the SCLx pin is held low (see Section 21.5.6
Clock Stretching for more detail). By stretching the
clock, the master will be unable to assert another clock
pulse until the slave is done preparing the transmit
data.

The transmit data must be loaded into the SSPxBUF

register which also loads the SSPxSR register. Then
the SCLx pin should be released by setting the CKP bit
of the SSPxCON1 register. The eight data bits are
shifted out on the falling edge of the SCLx input. This
ensures that the SDAx signal is valid during the SCLx
high time.
The ACK pulse from the master-receiver is latched on
the rising edge of the ninth SCLx input pulse. This ACK
value is copied to the ACKSTAT bit of the SSPxCON2
register. If ACKSTAT is set (not ACK), then the data
transfer is complete. In this case, when the not ACK is
latched by the slave, the slave goes idle and waits for
another occurrence of the Start bit. If the SDAx line was
low (ACK), the next transmit data must be loaded into
the SSPxBUF register. Again, the SCLx pin must be
released by setting bit CKP.
An MSSP interrupt is generated for each data transfer
byte. The SSPxIF bit must be cleared by software and
the SSPxSTAT register is used to determine the status
of the byte. The SSPxIF bit is set on the falling edge of
the ninth clock pulse.

21.5.3.1

Slave Mode Bus Collision

A slave receives a Read request and begins shifting

data out on the SDAx line. If a bus collision is detected
and the SBCDE bit of the SSPxCON3 register is set,
the BCLxIF bit of the PIRx register is set. Once a bus
collision is detected, the slave goes idle and waits to be
addressed again. User software can use the BCLxIF bit
to handle a slave bus collision.

DS41609A-page 204

Master sends a Start condition on SDAx and

SCLx.
2. S bit of SSPxSTAT is set; SSPxIF is set if interrupt on Start detect is enabled.
3. Matching address with R/W bit set is received by
the Slave setting SSPxIF bit.
4. Slave hardware generates an ACK and sets
SSPxIF.
5. SSPxIF bit is cleared by user.
6. Software reads the received address from
SSPxBUF, clearing BF.
7. R/W is set so CKP was automatically cleared
after the ACK.
8. The slave software loads the transmit data into
SSPxBUF.
9. CKP bit is set releasing SCLx, allowing the master to clock the data out of the slave.
10. SSPxIF is set after the ACK response from the
master is loaded into the ACKSTAT register.
11. SSPxIF bit is cleared.
12. The slave software checks the ACKSTAT bit to
see if the master wants to clock out more data.
Note 1: If the master ACKs the clock will be
stretched.
2: ACKSTAT is the only bit updated on the
rising edge of SCLx (9th) rather than the
falling.

13. Steps 9-13 are repeated for each transmitted

byte.
14. If the master sends a not ACK; the clock is not
held, but SSPxIF is still set.
15. The master sends a Restart condition or a Stop.
16. The slave is no longer addressed.

Preliminary

2011 Microchip Technology Inc.

Receiving Address
SDAx

R/W = 1 Automatic
ACK

D7 D6 D5 D4 D3 D2 D1 D0 ACK

D7 D6 D5 D4 D3 D2 D1 D0

Automatic

Transmitting Data

SSPxIF
Cleared by software
BF
Received address
is read from SSPxBUF

Data to transmit is
loaded into SSPxBUF

BF is automatically
cleared after 8th falling
edge of SCLx

Preliminary

CKP
When R/W is set
SCLx is always
held low after 9th SCLx
falling edge

Set by software

CKP is not
held for not
ACK

ACKSTAT

R/W
R/W is copied from the
matching address byte
D/A
Indicates an address
has been received
S

DS41609A-page 205

PIC16(L)F1508/9

Masters not ACK

is copied to
ACKSTAT

I2C SLAVE, 7-BIT ADDRESS, TRANSMISSION (AHEN = 0)

SCLx

Transmitting Data

ACK

A7 A6 A5 A4 A3 A2 A1

FIGURE 21-18:

2011 Microchip Technology Inc.

Master sends
Stop condition

PIC16(L)F1508/9
21.5.3.3

7-bit Transmission with Address

Hold Enabled

Setting the AHEN bit of the SSPxCON3 register

enables additional clock stretching and interrupt generation after the 8th falling edge of a received matching address. Once a matching address has been
clocked in, CKP is cleared and the SSPxIF interrupt is
set.
Figure 21-18 displays a standard waveform of a 7-bit
Address Slave Transmission with AHEN enabled.
1.
2.

Bus starts idle.

Master sends Start condition; the S bit of
SSPxSTAT is set; SSPxIF is set if interrupt on
Start detect is enabled.
3. Master sends matching address with R/W bit
set. After the 8th falling edge of the SCLx line the
CKP bit is cleared and SSPxIF interrupt is generated.
4. Slave software clears SSPxIF.
5. Slave software reads ACKTIM bit of SSPxCON3
register, and R/W and D/A of the SSPxSTAT
register to determine the source of the interrupt.
6. Slave reads the address value from the
SSPxBUF register clearing the BF bit.
7. Slave software decides from this information if it
wishes to ACK or not ACK and sets the ACKDT
bit of the SSPxCON2 register accordingly.
8. Slave sets the CKP bit releasing SCLx.
9. Master clocks in the ACK value from the slave.
10. Slave hardware automatically clears the CKP bit
and sets SSPxIF after the ACK if the R/W bit is
set.
11. Slave software clears SSPxIF.
12. Slave loads value to transmit to the master into
SSPxBUF setting the BF bit.
Note: SSPxBUF cannot be loaded until after the
ACK.

13. Slave sets CKP bit releasing the clock.

14. Master clocks out the data from the slave and
sends an ACK value on the 9th SCLx pulse.
15. Slave hardware copies the ACK value into the
ACKSTAT bit of the SSPxCON2 register.
16. Steps 10-15 are repeated for each byte transmitted to the master from the slave.
17. If the master sends a not ACK the slave
releases the bus allowing the master to send a
Stop and end the communication.
Note: Master must send a not ACK on the last byte
to ensure that the slave releases the SCLx
line to receive a Stop.

DS41609A-page 206

Preliminary

2011 Microchip Technology Inc.

Receiving Address

SCLx

Automatic

R/W = 1
ACK

A7 A6 A5 A4 A3 A2 A1
7

Transmitting Data
Automatic
D7 D6 D5 D4 D3 D2 D1 D0 ACK

D7 D6 D5 D4 D3 D2 D1 D0

Transmitting Data

SSPxIF
Cleared by software
BF
Received address
is read from SSPxBUF

Data to transmit is
loaded into SSPxBUF

BF is automatically
cleared after 8th falling
edge of SCLx

Preliminary

ACKDT
Slave clears
ACKDT to ACK
address
ACKSTAT

Masters ACK
response is copied
to SSPxSTAT
When AHEN = 1;
CKP is cleared by hardware
after receiving matching
address.

ACKTIM

DS41609A-page 207

R/W
D/A

ACKTIM is set on 8th falling

edge of SCLx

CKP not cleared

When R/W = 1;
CKP is always
cleared after ACK

Set by software,
releases SCLx

ACKTIM is cleared
on 9th rising edge of SCLx

after not ACK

PIC16(L)F1508/9

CKP

ACK

I2C SLAVE, 7-BIT ADDRESS, TRANSMISSION (AHEN = 1)

SDAx

FIGURE 21-19:

2011 Microchip Technology Inc.

Master sends
Stop condition

Master releases SDAx

to slave for ACK sequence

PIC16(L)F1508/9
21.5.4

SLAVE MODE 10-BIT ADDRESS

RECEPTION

21.5.5

This section describes a standard sequence of events

for the MSSP module configured as an I2C slave in
10-bit Addressing mode.
Figure 21-19 and is used as a visual reference for this
description.
This is a step by step process of what must be done by
slave software to accomplish I2C communication.
1.
2.

3.
4.
5.
6.
7.
8.

Bus starts idle.

Master sends Start condition; S bit of SSPxSTAT
is set; SSPxIF is set if interrupt on Start detect is
enabled.
Master sends matching high address with R/W
bit clear; UA bit of the SSPxSTAT register is set.
Slave sends ACK and SSPxIF is set.
Software clears the SSPxIF bit.
Software reads received address from
SSPxBUF clearing the BF flag.
Slave loads low address into SSPxADD,
releasing SCLx.
Master sends matching low address byte to the
Slave; UA bit is set.

10-BIT ADDRESSING WITH ADDRESS OR

DATA HOLD

Reception using 10-bit addressing with AHEN or

DHEN set is the same as with 7-bit modes. The only
difference is the need to update the SSPxADD register
using the UA bit. All functionality, specifically when the
CKP bit is cleared and SCLx line is held low are the
same. Figure 21-20 can be used as a reference of a
slave in 10-bit addressing with AHEN set.
Figure 21-21 shows a standard waveform for a slave
transmitter in 10-bit Addressing mode.

Note: Updates to the SSPxADD register are not

allowed until after the ACK sequence.

Slave sends ACK and SSPxIF is set.

Note: If the low address does not match, SSPxIF
and UA are still set so that the slave software can set SSPxADD back to the high
address. BF is not set because there is no
match. CKP is unaffected.

10. Slave clears SSPxIF.

11. Slave reads the received matching address
from SSPxBUF clearing BF.
12. Slave loads high address into SSPxADD.
13. Master clocks a data byte to the slave and
clocks out the slaves ACK on the 9th SCLx
pulse; SSPxIF is set.
14. If SEN bit of SSPxCON2 is set, CKP is cleared
by hardware and the clock is stretched.
15. Slave clears SSPxIF.
16. Slave reads the received byte from SSPxBUF
clearing BF.
17. If SEN is set the slave sets CKP to release the
SCLx.
18. Steps 13-17 repeat for each received byte.
19. Master sends Stop to end the transmission.

DS41609A-page 208

Preliminary

2011 Microchip Technology Inc.

SCLx
S

0 A9 A8

ACK

A7 A6 A5 A4 A3 A2 A1 A0 ACK

Receive Data

Receive Data
D7 D6 D5 D4 D3 D2 D1 D0 ACK

D7 D6 D5 D4 D3 D2 D1 D0 ACK

SCLx is held low

while CKP = 0

Preliminary

SSPxIF

Set by hardware
on 9th falling edge

Cleared by software

BF
Receive address is
read from SSPxBUF

If address matches
SSPxADD it is loaded into
SSPxBUF

Data is read
from SSPxBUF

When UA = 1;
SCLx is held low

Software updates SSPxADD

and releases SCLx

CKP

DS41609A-page 209

Set by software,
When SEN = 1;
releasing SCLx
CKP is cleared after
9th falling edge of received byte

PIC16(L)F1508/9

I2C SLAVE, 10-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 0, DHEN = 0)

Receive Second Address Byte

Receive First Address Byte

SDAx

FIGURE 21-20:

2011 Microchip Technology Inc.

Master sends
Stop condition

ACK

Receive Data

ACK

Receive Data

D0 ACK D7

D6 D5

SSPxIF
Set by hardware
on 9th falling edge

Cleared by software

Preliminary

BF
SSPxBUF can be
read anytime before
the next received byte

Received data
is read from
SSPxBUF

ACKDT
Slave software clears
ACKDT to ACK
the received byte
UA
Update to SSPxADD is
not allowed until 9th
falling edge of SCLx

2011 Microchip Technology Inc.

CKP

If when AHEN = 1;
on the 8th falling edge
of SCLx of an address
byte, CKP is cleared

ACKTIM
ACKTIM is set by hardware
on 8th falling edge of SCLx

Update of SSPxADD,
clears UA and releases
SCLx

Set CKP with software

releases SCLx

I2C SLAVE, 10-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 1, DHEN = 0)

SCLx

PIC16(L)F1508/9

SDAx

Receive Second Address Byte

R/W = 0

FIGURE 21-21:

DS41609A-page 210

Receive First Address Byte

FIGURE 21-22:

Receiving Address R/W = 0

1 1 1 1 0 A9 A8
ACK

SDAx

SCLx

Master sends
not ACK

Receiving Second Address Byte

Receive First Address Byte

A7 A6 A5 A4 A3 A2 A1 A0 ACK

1 1 1 1 0 A9 A8

7 8

2 3

7 8

Transmitting Data Byte

ACK

ACK = 1

D7 D6 D5 D4 D3 D2 D1 D0

Preliminary

SSPxIF
Set by hardware

Cleared by software

Set by hardware

BF
SSPxBUF loaded
with received address

Received address is
read from SSPxBUF

Data to transmit is
loaded into SSPxBUF

CKP

After SSPxADD is
updated, UA is cleared
and SCLx is released

High address is loaded

back into SSPxADD

When R/W = 1;
CKP is cleared on
9th falling edge of SCLx

ACKSTAT

Set by software
releases SCLx

Masters not ACK

is copied
R/W

DS41609A-page 211

R/W is copied from the

matching address byte

D/A
Indicates an address
has been received

PIC16(L)F1508/9

UA indicates SSPxADD
must be updated

Master sends
Stop condition

I2C SLAVE, 10-BIT ADDRESS, TRANSMISSION (SEN = 0, AHEN = 0, DHEN = 0)

2011 Microchip Technology Inc.

Master sends
Restart event

PIC16(L)F1508/9
21.5.6

21.5.6.2

CLOCK STRETCHING

Clock stretching occurs when a device on the bus

holds the SCLx line low, effectively pausing communication. The slave may stretch the clock to allow more
time to handle data or prepare a response for the master device. A master device is not concerned with
stretching as anytime it is active on the bus and not
transferring data it is stretching. Any stretching done
by a slave is invisible to the master software and handled by the hardware that generates SCLx.
The CKP bit of the SSPxCON1 register is used to control stretching in software. Any time the CKP bit is
cleared, the module will wait for the SCLx line to go
low and then hold it. Setting CKP will release SCLx
and allow more communication.
21.5.6.1

Normal Clock Stretching

Following an ACK if the R/W bit of SSPxSTAT is set, a

read request, the slave hardware will clear CKP. This
allows the slave time to update SSPxBUF with data to
transfer to the master. If the SEN bit of SSPxCON2 is
set, the slave hardware will always stretch the clock
after the ACK sequence. Once the slave is ready, CKP
is set by software and communication resumes.
Note 1: The BF bit has no effect on if the clock will
be stretched or not. This is different than
previous versions of the module that
would not stretch the clock, clear CKP, if
SSPxBUF was read before the 9th falling
edge of SCLx.
2: Previous versions of the module did not
stretch the clock for a transmission if
SSPxBUF was loaded before the 9th falling edge of SCLx. It is now always cleared
for read requests.

FIGURE 21-23:

10-bit Addressing Mode

In 10-bit Addressing mode, when the UA bit is set, the

clock is always stretched. This is the only time the
SCLx is stretched without CKP being cleared. SCLx is
released immediately after a write to SSPxADD.
Note: Previous versions of the module did not
stretch the clock if the second address byte
did not match.

21.5.6.3

Byte NACKing

When the AHEN bit of SSPxCON3 is set; CKP is

cleared by hardware after the 8th falling edge of SCLx
for a received matching address byte. When the
DHEN bit of SSPxCON3 is set, CKP is cleared after
the 8th falling edge of SCLx for received data.
Stretching after the 8th falling edge of SCLx allows the
slave to look at the received address or data and
decide if it wants to ACK the received data.
21.5.7

CLOCK SYNCHRONIZATION AND

THE CKP BIT

Any time the CKP bit is cleared, the module will wait
for the SCLx line to go low and then hold it. However,
clearing the CKP bit will not assert the SCLx output
low until the SCLx output is already sampled low.
Therefore, the CKP bit will not assert the SCLx line
until an external I2C master device has already
asserted the SCLx line. The SCLx output will remain
low until the CKP bit is set and all other devices on the
I2C bus have released SCLx. This ensures that a write
to the CKP bit will not violate the minimum high time
requirement for SCLx (see Figure 21-22).

CLOCK SYNCHRONIZATION TIMING

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

SDAx

DX 1

SCLx

CKP

Master device
asserts clock
Master device
releases clock

WR
SSPxCON1

DS41609A-page 212

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.5.8

In 10-bit Address mode, the UA bit will not be set on

the reception of the general call address. The slave
will prepare to receive the second byte as data, just as
it would in 7-bit mode.

GENERAL CALL ADDRESS SUPPORT

The addressing procedure for the I2C bus is such that

the first byte after the Start condition usually determines which device will be the slave addressed by the
master device. The exception is the general call
address which can address all devices. When this
address is used, all devices should, in theory, respond
with an acknowledge.

If the AHEN bit of the SSPxCON3 register is set, just

as with any other address reception, the slave hardware will stretch the clock after the 8th falling edge of
SCLx. The slave must then set its ACKDT value and
release the clock with communication progressing as it
would normally.

The general call address is a reserved address in the

I2C protocol, defined as address 0x00. When the
GCEN bit of the SSPxCON2 register is set, the slave
module will automatically ACK the reception of this
address regardless of the value stored in SSPxADD.
After the slave clocks in an address of all zeros with
the R/W bit clear, an interrupt is generated and slave
software can read SSPxBUF and respond.
Figure 21-23 shows a General Call reception
sequence.

FIGURE 21-24:

SLAVE MODE GENERAL CALL ADDRESS SEQUENCE

Address is compared to General Call Address
after ACK, set interrupt
R/W = 0
ACK D7

General Call Address

SDAx
SCLx
S

Receiving Data

ACK

SSPxIF
BF (SSPxSTAT<0>)
Cleared by software
SSPxBUF is read

GCEN (SSPxCON2<7>)

21.5.9

SSPx MASK REGISTER

An SSPx Mask (SSPxMSK) register (Register 21-5) is

available in I2C Slave mode as a mask for the value
held in the SSPxSR register during an address
comparison operation. A zero (0) bit in the SSPxMSK
register has the effect of making the corresponding bit
of the received address a dont care.
This register is reset to all 1s upon any Reset
condition and, therefore, has no effect on standard
SSPx operation until written with a mask value.
The SSPx Mask register is active during:
7-bit Address mode: address compare of A<7:1>.
10-bit Address mode: address compare of A<7:0>
only. The SSPx mask has no effect during the
reception of the first (high) byte of the address.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 213

PIC16(L)F1508/9
21.6

I2C MASTER MODE

21.6.1

Master mode is enabled by setting and clearing the

appropriate SSPM bits in the SSPxCON1 register and
by setting the SSPEN bit. In Master mode, the SDAx
and SCKx pins must be configured as inputs. The
MSSP peripheral hardware will override the output
driver TRIS controls when necessary to drive the pins
low.
Master mode of operation is supported by interrupt
generation on the detection of the Start and Stop conditions. The Stop (P) and Start (S) bits are cleared from
a Reset or when the MSSPx module is disabled. Control of the I 2C bus may be taken when the P bit is set,
or the bus is idle.
In Firmware Controlled Master mode, user code
conducts all I 2C bus operations based on Start and
Stop bit condition detection. Start and Stop condition
detection is the only active circuitry in this mode. All
other communication is done by the user software
directly manipulating the SDAx and SCLx lines.
The following events will cause the SSPx Interrupt Flag
bit, SSPxIF, to be set (SSPx interrupt, if enabled):

Start condition detected

Stop condition detected
Data transfer byte transmitted/received
Acknowledge transmitted/received
Repeated Start generated

I2C MASTER MODE OPERATION

The master device generates all of the serial clock

pulses and the Start and Stop conditions. A transfer is
ended with a Stop condition or with a Repeated Start
condition. Since the Repeated Start condition is also
the beginning of the next serial transfer, the I2C bus will
not be released.
In Master Transmitter mode, serial data is output
through SDAx, while SCLx outputs the serial clock. The
first byte transmitted contains the slave address of the
receiving device (7 bits) and the Read/Write (R/W) bit.
In this case, the R/W bit will be logic 0. Serial data is
transmitted 8 bits at a time. After each byte is transmitted, an Acknowledge bit is received. Start and Stop
conditions are output to indicate the beginning and the
end of a serial transfer.
In Master Receive mode, the first byte transmitted contains the slave address of the transmitting device
(7 bits) and the R/W bit. In this case, the R/W bit will be
logic 1. Thus, the first byte transmitted is a 7-bit slave
address followed by a 1 to indicate the receive bit.
Serial data is received via SDAx, while SCLx outputs
the serial clock. Serial data is received 8 bits at a time.
After each byte is received, an Acknowledge bit is
transmitted. Start and Stop conditions indicate the
beginning and end of transmission.
A Baud Rate Generator is used to set the clock frequency output on SCLx. See Section 21.7 Baud
Rate Generator for more detail.

Note 1: The MSSPx module, when configured in

I2C Master mode, does not allow queueing of events. For instance, the user is not
allowed to initiate a Start condition and
immediately write the SSPxBUF register
to initiate transmission before the Start
condition is complete. In this case, the
SSPxBUF will not be written to and the
WCOL bit will be set, indicating that a
write to the SSPxBUF did not occur
2: When in Master mode, Start/Stop detection is masked and an interrupt is generated when the SEN/PEN bit is cleared and
the generation is complete.

DS41609A-page 214

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.6.2

CLOCK ARBITRATION

Clock arbitration occurs when the master, during any

receive, transmit or Repeated Start/Stop condition,
releases the SCLx pin (SCLx allowed to float high).
When the SCLx pin is allowed to float high, the Baud
Rate Generator (BRG) is suspended from counting
until the SCLx pin is actually sampled high. When the
SCLx pin is sampled high, the Baud Rate Generator is
reloaded with the contents of SSPxADD<7:0> and
begins counting. This ensures that the SCLx high time
will always be at least one BRG rollover count in the
event that the clock is held low by an external device
(Figure 21-25).

FIGURE 21-25:

BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION

SDAx

DX 1

DX
SCLx deasserted but slave holds
SCLx low (clock arbitration)

SCLx allowed to transition high

SCLx
BRG decrements on
Q2 and Q4 cycles
BRG
Value

03h

02h

01h

00h (hold off)

03h

02h

SCLx is sampled high, reload takes

place and BRG starts its count
BRG
Reload

21.6.3

WCOL STATUS FLAG

If the user writes the SSPxBUF when a Start, Restart,

Stop, Receive or Transmit sequence is in progress, the
WCOL bit is set and the contents of the buffer are
unchanged (the write does not occur). Any time the
WCOL bit is set it indicates that an action on SSPxBUF
was attempted while the module was not idle.
Note:

Because queueing of events is not

allowed, writing to the lower 5 bits of
SSPxCON2 is disabled until the Start
condition is complete.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 215

PIC16(L)F1508/9
21.6.4

I2C MASTER MODE START

by hardware; the Baud Rate Generator is suspended,

leaving the SDAx line held low and the Start condition
is complete.

CONDITION TIMING

To initiate a Start condition, the user sets the Start

Enable bit, SEN bit of the SSPxCON2 register. If the
SDAx and SCLx pins are sampled high, the Baud Rate
Generator is reloaded with the contents of
SSPxADD<7:0> and starts its count. If SCLx and
SDAx are both sampled high when the Baud Rate
Generator times out (TBRG), the SDAx pin is driven
low. The action of the SDAx being driven low while
SCLx is high is the Start condition and causes the S bit
of the SSPxSTAT1 register to be set. Following this,
the Baud Rate Generator is reloaded with the contents
of SSPxADD<7:0> and resumes its count. When the
Baud Rate Generator times out (TBRG), the SEN bit of
the SSPxCON2 register will be automatically cleared

FIGURE 21-26:

Note 1: If at the beginning of the Start condition,

the SDAx and SCLx pins are already sampled low, or if during the Start condition,
the SCLx line is sampled low before the
SDAx line is driven low, a bus collision
occurs, the Bus Collision Interrupt Flag,
BCLxIF, is set, the Start condition is
aborted and the I2C module is reset into
its Idle state.
2: The Philips I2C Specification states that a
bus collision cannot occur on a Start.

FIRST START BIT TIMING

Set S bit (SSPxSTAT<3>)

Write to SEN bit occurs here

At completion of Start bit,

hardware clears SEN bit
and sets SSPxIF bit

SDAx = 1,
SCLx = 1
TBRG

TBRG

Write to SSPxBUF occurs here

SDAx

1st bit

2nd bit

TBRG
SCLx
S

DS41609A-page 216

Preliminary

TBRG

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.6.5

I2C MASTER MODE REPEATED

SSPxCON2 register will be automatically cleared and

the Baud Rate Generator will not be reloaded, leaving
the SDAx pin held low. As soon as a Start condition is
detected on the SDAx and SCLx pins, the S bit of the
SSPxSTAT register will be set. The SSPxIF bit will not
be set until the Baud Rate Generator has timed out.

START CONDITION TIMING

A Repeated Start condition occurs when the RSEN bit

of the SSPxCON2 register is programmed high and the
master state machine is no longer active. When the
RSEN bit is set, the SCLx pin is asserted low. When the
SCLx pin is sampled low, the Baud Rate Generator is
loaded and begins counting. The SDAx pin is released
(brought high) for one Baud Rate Generator count
(TBRG). When the Baud Rate Generator times out, if
SDAx is sampled high, the SCLx pin will be deasserted
(brought high). When SCLx is sampled high, the Baud
Rate Generator is reloaded and begins counting. SDAx
and SCLx must be sampled high for one TBRG. This
action is then followed by assertion of the SDAx pin
(SDAx = 0) for one TBRG while SCLx is high. SCLx is
asserted low. Following this, the RSEN bit of the

FIGURE 21-27:

Note 1: If RSEN is programmed while any other

event is in progress, it will not take effect.
2: A bus collision during the Repeated Start
condition occurs if:

SDAx is sampled low when SCLx

goes from low-to-high.
SCLx goes low before SDAx is
asserted low. This may indicate
that another master is attempting to
transmit a data 1.

REPEAT START CONDITION WAVEFORM

S bit set by hardware

Write to SSPxCON2
occurs here
SDAx = 1,
SCLx (no change)

At completion of Start bit,

hardware clears RSEN bit
and sets SSPxIF

SDAx = 1,
SCLx = 1
TBRG

TBRG

TBRG
1st bit

SDAx

Write to SSPxBUF occurs here

TBRG
SCLx

TBRG

Repeated Start

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 217

PIC16(L)F1508/9
21.6.6

I2C MASTER MODE TRANSMISSION

21.6.6.3

Transmission of a data byte, a 7-bit address or the

other half of a 10-bit address is accomplished by simply
writing a value to the SSPxBUF register. This action will
set the Buffer Full flag bit, BF, and allow the Baud Rate
Generator to begin counting and start the next transmission. Each bit of address/data will be shifted out
onto the SDAx pin after the falling edge of SCLx is
asserted. SCLx is held low for one Baud Rate Generator rollover count (TBRG). Data should be valid before
SCLx is released high. When the SCLx pin is released
high, it is held that way for TBRG. The data on the SDAx
pin must remain stable for that duration and some hold
time after the next falling edge of SCLx. After the eighth
bit is shifted out (the falling edge of the eighth clock),
the BF flag is cleared and the master releases SDAx.
This allows the slave device being addressed to
respond with an ACK bit during the ninth bit time if an
address match occurred, or if data was received properly. The status of ACK is written into the ACKSTAT bit
on the rising edge of the ninth clock. If the master
receives an Acknowledge, the Acknowledge Status bit,
ACKSTAT, is cleared. If not, the bit is set. After the ninth
clock, the SSPxIF bit is set and the master clock (Baud
Rate Generator) is suspended until the next data byte
is loaded into the SSPxBUF, leaving SCLx low and
SDAx unchanged (Figure 21-27).
After the write to the SSPxBUF, each bit of the address
will be shifted out on the falling edge of SCLx until all
seven address bits and the R/W bit are completed. On
the falling edge of the eighth clock, the master will
release the SDAx pin, allowing the slave to respond
with an Acknowledge. On the falling edge of the ninth
clock, the master will sample the SDAx pin to see if the
address was recognized by a slave. The status of the
ACK bit is loaded into the ACKSTAT Status bit of the
SSPxCON2 register. Following the falling edge of the
ninth clock transmission of the address, the SSPxIF is
set, the BF flag is cleared and the Baud Rate Generator
is turned off until another write to the SSPxBUF takes
place, holding SCLx low and allowing SDAx to float.

21.6.6.1

ACKSTAT Status Flag

In Transmit mode, the ACKSTAT bit of the SSPxCON2

register is cleared when the slave has sent an Acknowledge (ACK = 0) and is set when the slave does not
Acknowledge (ACK = 1). A slave sends an Acknowledge when it has recognized its address (including a
general call), or when the slave has properly received
its data.
21.6.6.4
1.
2.
3.
4.
5.
6.

9.
10.
11.

12.
13.

BF Status Flag

Typical transmit sequence:

The user generates a Start condition by setting

the SEN bit of the SSPxCON2 register.
SSPxIF is set by hardware on completion of the
Start.
SSPxIF is cleared by software.
The MSSPx module will wait the required start
time before any other operation takes place.
The user loads the SSPxBUF with the slave
address to transmit.
Address is shifted out the SDAx pin until all 8 bits
are transmitted. Transmission begins as soon
as SSPxBUF is written to.
The MSSPx module shifts in the ACK bit from
the slave device and writes its value into the
ACKSTAT bit of the SSPxCON2 register.
The MSSPx module generates an interrupt at
the end of the ninth clock cycle by setting the
SSPxIF bit.
The user loads the SSPxBUF with eight bits of
data.
Data is shifted out the SDAx pin until all 8 bits
are transmitted.
The MSSPx module shifts in the ACK bit from
the slave device and writes its value into the
ACKSTAT bit of the SSPxCON2 register.
Steps 8-11 are repeated for all transmitted data
bytes.
The user generates a Stop or Restart condition
by setting the PEN or RSEN bits of the
SSPxCON2 register. Interrupt is generated once
the Stop/Restart condition is complete.

In Transmit mode, the BF bit of the SSPxSTAT register

is set when the CPU writes to SSPxBUF and is cleared
when all 8 bits are shifted out.

21.6.6.2

WCOL Status Flag

If the user writes the SSPxBUF when a transmit is

already in progress (i.e., SSPxSR is still shifting out a
data byte), the WCOL bit is set and the contents of the
buffer are unchanged (the write does not occur).
WCOL must be cleared by software before the next
transmission.

DS41609A-page 218

Preliminary

2011 Microchip Technology Inc.

FIGURE 21-28:

SEN = 0
Transmit Address to Slave
SDAx

ACKSTAT in
SSPxCON2 = 1

From slave, clear ACKSTAT bit SSPxCON2<6>

Transmitting Data or Second Half

of 10-bit Address

R/W = 0

ACK = 0

ACK

1
SCLx held low
while CPU
responds to SSPxIF

SSPxBUF written with 7-bit address and R/W

start transmit
SCLx

Preliminary

SSPxIF
Cleared by software

Cleared by software service routine

from SSP interrupt

BF (SSPxSTAT<0>)
SSPxBUF written
SEN

PEN

R/W

DS41609A-page 219

PIC16(L)F1508/9

After Start condition, SEN cleared by hardware

SSPxBUF is written by software

Cleared by software

I2C MASTER MODE WAVEFORM (TRANSMISSION, 7 OR 10-BIT ADDRESS)

2011 Microchip Technology Inc.

Write SSPxCON2<0> SEN = 1

Start condition begins

PIC16(L)F1508/9
21.6.7

I2C MASTER MODE RECEPTION

21.6.7.4

Master mode reception is enabled by programming the

Receive Enable bit, RCEN bit of the SSPxCON2
register.
Note:

The MSSPx module must be in an Idle

state before the RCEN bit is set or the
RCEN bit will be disregarded.

The Baud Rate Generator begins counting and on each

rollover, the state of the SCLx pin changes
(high-to-low/low-to-high) and data is shifted into the
SSPxSR. After the falling edge of the eighth clock, the
receive enable flag is automatically cleared, the contents of the SSPxSR are loaded into the SSPxBUF, the
BF flag bit is set, the SSPxIF flag bit is set and the Baud
Rate Generator is suspended from counting, holding
SCLx low. The MSSP is now in Idle state awaiting the
next command. When the buffer is read by the CPU,
the BF flag bit is automatically cleared. The user can
then send an Acknowledge bit at the end of reception
by setting the Acknowledge Sequence Enable, ACKEN
bit of the SSPxCON2 register.

21.6.7.1

1.
2.
3.
4.
5.

8.
9.
10.

BF Status Flag

In receive operation, the BF bit is set when an address

or data byte is loaded into SSPxBUF from SSPxSR. It
is cleared when the SSPxBUF register is read.

11.

21.6.7.2

12.

SSPOV Status Flag

In receive operation, the SSPOV bit is set when 8 bits

are received into the SSPxSR and the BF flag bit is
already set from a previous reception.

13.
14.

21.6.7.3

15.

WCOL Status Flag

If the user writes the SSPxBUF when a receive is

already in progress (i.e., SSPxSR is still shifting in a
data byte), the WCOL bit is set and the contents of the
buffer are unchanged (the write does not occur).

DS41609A-page 220

Preliminary

Typical Receive Sequence:

The user generates a Start condition by setting

the SEN bit of the SSPxCON2 register.
SSPxIF is set by hardware on completion of the
Start.
SSPxIF is cleared by software.
User writes SSPxBUF with the slave address to
transmit and the R/W bit set.
Address is shifted out the SDAx pin until all 8 bits
are transmitted. Transmission begins as soon
as SSPxBUF is written to.
The MSSP module shifts in the ACK bit from the
slave device and writes its value into the
ACKSTAT bit of the SSPxCON2 register.
The MSSP module generates an interrupt at the
end of the ninth clock cycle by setting the
SSPxIF bit.
User sets the RCEN bit of the SSPxCON2 register and the Master clocks in a byte from the slave.
After the 8th falling edge of SCLx, SSPxIF and
BF are set.
Master clears SSPxIF and reads the received
byte from SSPxBUF, clears BF.
Master sets ACK value sent to slave in ACKDT
bit of the SSPxCON2 register and initiates the
ACK by setting the ACKEN bit.
Masters ACK is clocked out to the Slave and
SSPxIF is set.
User clears SSPxIF.
Steps 8-13 are repeated for each received byte
from the slave.
Master sends a not ACK or Stop to end
communication.

2011 Microchip Technology Inc.

Write to SSPxCON2<0>(SEN = 1),

begin Start condition

Receiving Data from Slave

A1 R/W

ACK

PEN bit = 1
written here

RCEN cleared
automatically

D7 D6 D5 D4 D3 D2 D1

ACK

D7 D6 D5 D4 D3 D2 D1

ACK
Bus master
terminates
transfer

ACK is not sent

SCLx

Data shifted in on falling edge of CLK

Preliminary

Set SSPxIF interrupt

at end of receive

Cleared by software

BF
(SSPxSTAT<0>)

Set SSPxIF at end

of receive

Set SSPxIF interrupt

at end of Acknowledge
sequence

SSPxIF
SDAx = 0, SCLx = 1
while CPU
responds to SSPxIF

Cleared by software

Cleared in
software

Last bit is shifted into SSPxSR and

contents are unloaded into SSPxBUF

SSPOV is set because

SSPxBUF is still full

ACKEN

DS41609A-page 221

RCEN

Master configured as a receiver

by programming SSPxCON2<3> (RCEN = 1)

RCEN cleared
automatically

ACK from Master

SDAx = ACKDT = 0

RCEN cleared
automatically

Set P bit
(SSPxSTAT<4>)
and SSPxIF

PIC16(L)F1508/9

SSPOV

Set SSPxIF interrupt

at end of Acknowledge sequence

I2C MASTER MODE WAVEFORM (RECEPTION, 7-BIT ADDRESS)

A6 A5 A4 A3 A2

RCEN = 1, start
next receive

RCEN cleared
automatically

Transmit Address to Slave

Set ACKEN, start Acknowledge sequence

SDAx = ACKDT = 1

ACK from Master

SDAx = ACKDT = 0

Master configured as a receiver

by programming SSPxCON2<3> (RCEN = 1)

SEN = 0
Write to SSPxBUF occurs here,
ACK from Slave
start XMIT

SDAx

FIGURE 21-29:

2011 Microchip Technology Inc.

Write to SSPxCON2<4>
to start Acknowledge sequence
SDAx = ACKDT (SSPxCON2<5>) = 0

PIC16(L)F1508/9
21.6.8

ACKNOWLEDGE SEQUENCE
TIMING

21.6.9

A Stop bit is asserted on the SDAx pin at the end of a

receive/transmit by setting the Stop Sequence Enable
bit, PEN bit of the SSPxCON2 register. At the end of a
receive/transmit, the SCLx line is held low after the
falling edge of the ninth clock. When the PEN bit is set,
the master will assert the SDAx line low. When the
SDAx line is sampled low, the Baud Rate Generator is
reloaded and counts down to 0. When the Baud Rate
Generator times out, the SCLx pin will be brought high
and one TBRG (Baud Rate Generator rollover count)
later, the SDAx pin will be deasserted. When the SDAx
pin is sampled high while SCLx is high, the P bit of the
SSPxSTAT register is set. A TBRG later, the PEN bit is
cleared and the SSPxIF bit is set (Figure 21-30).

An Acknowledge sequence is enabled by setting the

Acknowledge Sequence Enable bit, ACKEN bit of the
SSPxCON2 register. When this bit is set, the SCLx pin is
pulled low and the contents of the Acknowledge data bit
are presented on the SDAx pin. If the user wishes to
generate an Acknowledge, then the ACKDT bit should
be cleared. If not, the user should set the ACKDT bit
before starting an Acknowledge sequence. The Baud
Rate Generator then counts for one rollover period
(TBRG) and the SCLx pin is deasserted (pulled high).
When the SCLx pin is sampled high (clock arbitration),
the Baud Rate Generator counts for TBRG. The SCLx pin
is then pulled low. Following this, the ACKEN bit is automatically cleared, the Baud Rate Generator is turned off
and the MSSP module then goes into Idle mode
(Figure 21-29).

21.6.8.1

21.6.9.1

WCOL Status Flag

If the user writes the SSPxBUF when a Stop sequence

is in progress, then the WCOL bit is set and the
contents of the buffer are unchanged (the write does
not occur).

WCOL Status Flag

If the user writes the SSPxBUF when an Acknowledge

sequence is in progress, then the WCOL bit is set and
the contents of the buffer are unchanged (the write
does not occur).

FIGURE 21-30:

STOP CONDITION TIMING

ACKNOWLEDGE SEQUENCE WAVEFORM

Acknowledge sequence starts here,
write to SSPxCON2
ACKEN = 1, ACKDT = 0

ACKEN automatically cleared

TBRG

TBRG
SDAx
SCLx

ACK

D0
8

SSPxIF
SSPxIF set at
the end of receive

Cleared in
software

Cleared in
software
SSPxIF set at the end
of Acknowledge sequence

Note: TBRG = one Baud Rate Generator period.

DS41609A-page 222

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 21-31:

STOP CONDITION RECEIVE OR TRANSMIT MODE

SCLx = 1 for TBRG, followed by SDAx = 1 for TBRG
after SDAx sampled high. P bit (SSPxSTAT<4>) is set.

Write to SSPxCON2,
set PEN

PEN bit (SSPxCON2<2>) is cleared by

hardware and the SSPxIF bit is set

Falling edge of
9th clock
TBRG

SCLx

SDAx

ACK
P

TBRG

SCLx brought high after TBRG

SDAx asserted low before rising edge of clock
to setup Stop condition

Note: TBRG = one Baud Rate Generator period.

21.6.10

SLEEP OPERATION

21.6.13

the I2C slave

While in Sleep mode,

module can receive
addresses or data and when an address match or
complete byte transfer occurs, wake the processor
from Sleep (if the MSSP interrupt is enabled).

21.6.11

EFFECTS OF A RESET

A Reset disables the MSSP module and terminates the

current transfer.

21.6.12

MULTI-MASTER MODE

In Multi-Master mode, the interrupt generation on the

detection of the Start and Stop conditions allows the
determination of when the bus is free. The Stop (P) and
Start (S) bits are cleared from a Reset or when the
MSSP module is disabled. Control of the I 2C bus may
be taken when the P bit of the SSPxSTAT register is
set, or the bus is idle, with both the S and P bits clear.
When the bus is busy, enabling the SSP interrupt will
generate the interrupt when the Stop condition occurs.
In multi-master operation, the SDAx line must be
monitored for arbitration to see if the signal level is the
expected output level. This check is performed by
hardware with the result placed in the BCLxIF bit.
The states where arbitration can be lost are:

Address Transfer
Data Transfer
A Start Condition
A Repeated Start Condition
An Acknowledge Condition

MULTI -MASTER COMMUNICATION,

BUS COLLISION AND BUS
ARBITRATION

Multi-Master mode support is achieved by bus arbitration. When the master outputs address/data bits onto
the SDAx pin, arbitration takes place when the master
outputs a 1 on SDAx, by letting SDAx float high and
another master asserts a 0. When the SCLx pin floats
high, data should be stable. If the expected data on
SDAx is a 1 and the data sampled on the SDAx pin is
0, then a bus collision has taken place. The master will
set the Bus Collision Interrupt Flag, BCLxIF and reset
the I2C port to its Idle state (Figure 21-31).
If a transmit was in progress when the bus collision
occurred, the transmission is halted, the BF flag is
cleared, the SDAx and SCLx lines are deasserted and
the SSPxBUF can be written to. When the user services the bus collision Interrupt Service Routine and if
the I2C bus is free, the user can resume communication by asserting a Start condition.
If a Start, Repeated Start, Stop or Acknowledge condition was in progress when the bus collision occurred, the
condition is aborted, the SDAx and SCLx lines are deasserted and the respective control bits in the SSPxCON2
register are cleared. When the user services the bus collision Interrupt Service Routine and if the I2C bus is free,
the user can resume communication by asserting a Start
condition.
The master will continue to monitor the SDAx and SCLx
pins. If a Stop condition occurs, the SSPxIF bit will be set.
A write to the SSPxBUF will start the transmission of
data at the first data bit, regardless of where the
transmitter left off when the bus collision occurred.
In Multi-Master mode, the interrupt generation on the
detection of Start and Stop conditions allows the determination of when the bus is free. Control of the I2C bus
can be taken when the P bit is set in the SSPxSTAT
register, or the bus is idle and the S and P bits are
cleared.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 223

PIC16(L)F1508/9
FIGURE 21-32:

BUS COLLISION TIMING FOR TRANSMIT AND ACKNOWLEDGE

Data changes
while SCLx = 0

SDAx line pulled low

by another source
SDAx released
by master

Sample SDAx. While SCLx is high,

data does not match what is driven
by the master.
Bus collision has occurred.

SDAx

SCLx

Set bus collision

interrupt (BCLxIF)

BCLxIF

DS41609A-page 224

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.6.13.1

Bus Collision During a Start

Condition

During a Start condition, a bus collision occurs if:

a)
b)

SDA or SCL are sampled low at the beginning of

the Start condition (Figure 21-32).
SCL is sampled low before SDAx is asserted
low (Figure 21-33).

During a Start condition, both the SDAx and the SCL

pins are monitored.

If the SDAx pin is sampled low during this count, the

BRG is reset and the SDAx line is asserted early
(Figure 21-34). If, however, a 1 is sampled on the SDA
pin, the SDA pin is asserted low at the end of the BRG
count. The Baud Rate Generator is then reloaded and
counts down to zero; if the SCL pin is sampled as 0
during this time, a bus collision does not occur. At the
end of the BRG count, the SCL pin is asserted low.
Note:

If the SDA pin is already low, or the SCL pin is already

low, then all of the following occur:
the Start condition is aborted,
the BCL1IF flag is set and
the MSSP module is reset to its Idle state
(Figure 21-32).
The Start condition begins with the SDAx and SCLx
pins deasserted. When the SDAx pin is sampled high,
the Baud Rate Generator is loaded and counts down. If
the SCLx pin is sampled low while SDAx is high, a bus
collision occurs because it is assumed that another
master is attempting to drive a data 1 during the Start
condition.

FIGURE 21-33:

The reason that bus collision is not a factor during a Start condition is that no two
bus masters can assert a Start condition
at the exact same time. Therefore, one
master will always assert SDAx before the
other. This condition does not cause a bus
collision because the two masters must be
allowed to arbitrate the first address following the Start condition. If the address is
the same, arbitration must be allowed to
continue into the data portion, Repeated
Start or Stop conditions.

BUS COLLISION DURING START CONDITION (SDAX ONLY)

SDAx goes low before the SEN bit is set.
Set BCLxIF,
S bit and SSPxIF set because
SDAx = 0, SCLx = 1.

SDAx

SCLx
Set SEN, enable Start
condition if SDAx = 1, SCLx = 1

SEN cleared automatically because of bus collision.

SSP module reset into Idle state.

SEN

BCLxIF

SDAx sampled low before

Start condition. Set BCLxIF.
S bit and SSPxIF set because
SDAx = 0, SCLx = 1.
SSPxIF and BCLxIF are
cleared by software

SSPxIF
SSPxIF and BCLxIF are
cleared by software

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 225

PIC16(L)F1508/9
FIGURE 21-34:

BUS COLLISION DURING START CONDITION (SCLX = 0)

SDAx = 0, SCLx = 1
TBRG

TBRG

SDAx
Set SEN, enable Start
sequence if SDAx = 1, SCLx = 1

SCLx

SCLx = 0 before SDAx = 0,

bus collision occurs. Set BCLxIF.

SEN
SCLx = 0 before BRG time-out,
bus collision occurs. Set BCLxIF.
BCLxIF

Interrupt cleared
by software
S

SSPxIF

FIGURE 21-35:

BRG RESET DUE TO SDA ARBITRATION DURING START CONDITION

SDAx = 0, SCLx = 1
Set S
Less than TBRG

SDAx

SCLx

TBRG

SDAx pulled low by other master.

Reset BRG and assert SDAx.

S
SCLx pulled low after BRG
time-out

SEN
BCLxIF

Set SSPxIF

Set SEN, enable Start

sequence if SDAx = 1, SCLx = 1

SSPxIF
SDAx = 0, SCLx = 1,
set SSPxIF

DS41609A-page 226

Preliminary

Interrupts cleared
by software

2011 Microchip Technology Inc.

PIC16(L)F1508/9
21.6.13.2

Bus Collision During a Repeated

Start Condition

If SDAx is low, a bus collision has occurred (i.e., another

master is attempting to transmit a data 0, Figure 21-35).
If SDAx is sampled high, the BRG is reloaded and
begins counting. If SDAx goes from high-to-low before
the BRG times out, no bus collision occurs because no
two masters can assert SDAx at exactly the same time.

During a Repeated Start condition, a bus collision

occurs if:
a)
b)

A low level is sampled on SDAx when SCLx

goes from low level to high level.
SCLx goes low before SDAx is asserted low,
indicating that another master is attempting to
transmit a data 1.

If SCLx goes from high-to-low before the BRG times

out and SDAx has not already been asserted, a bus
collision occurs. In this case, another master is
attempting to transmit a data 1 during the Repeated
Start condition, see Figure 21-36.

When the user releases SDAx and the pin is allowed to

float high, the BRG is loaded with SSPxADD and
counts down to zero. The SCLx pin is then deasserted
and when sampled high, the SDAx pin is sampled.

FIGURE 21-36:

If, at the end of the BRG time-out, both SCLx and SDAx
are still high, the SDAx pin is driven low and the BRG
is reloaded and begins counting. At the end of the
count, regardless of the status of the SCLx pin, the
SCLx pin is driven low and the Repeated Start
condition is complete.

BUS COLLISION DURING A REPEATED START CONDITION (CASE 1)

SDAx

SCLx
Sample SDAx when SCLx goes high.
If SDAx = 0, set BCLxIF and release SDAx and SCLx.
RSEN

BCLxIF
Cleared by software
S

SSPxIF

FIGURE 21-37:

BUS COLLISION DURING REPEATED START CONDITION (CASE 2)

TBRG

SDAx
SCLx

BCLxIF

SCLx goes low before SDAx,

set BCLxIF. Release SDAx and SCLx.
Interrupt cleared
by software

RSEN

S
SSPxIF

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 227

PIC16(L)F1508/9
21.6.13.3

Bus Collision During a Stop

Condition

The Stop condition begins with SDAx asserted low.

When SDAx is sampled low, the SCLx pin is allowed to
float. When the pin is sampled high (clock arbitration),
the Baud Rate Generator is loaded with SSPxADD and
counts down to 0. After the BRG times out, SDAx is
sampled. If SDAx is sampled low, a bus collision has
occurred. This is due to another master attempting to
drive a data 0 (Figure 21-37). If the SCLx pin is
sampled low before SDAx is allowed to float high, a bus
collision occurs. This is another case of another master
attempting to drive a data 0 (Figure 21-38).

Bus collision occurs during a Stop condition if:

After the SDAx pin has been deasserted and

allowed to float high, SDAx is sampled low after
the BRG has timed out.
After the SCLx pin is deasserted, SCLx is
sampled low before SDAx goes high.

FIGURE 21-38:

BUS COLLISION DURING A STOP CONDITION (CASE 1)

TBRG

SDAx sampled
low after TBRG,
set BCLxIF

TBRG

SDAx
SDAx asserted low
SCLx
PEN
BCLxIF
P

SSPxIF

FIGURE 21-39:

BUS COLLISION DURING A STOP CONDITION (CASE 2)

TBRG

SDAx
SCLx goes low before SDAx goes high,
set BCLxIF

Assert SDAx
SCLx
PEN
BCLxIF
P

SSPxIF

DS41609A-page 228

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 21-3:
Name
INTCON

SUMMARY OF REGISTERS ASSOCIATED WITH I2C OPERATION

Bit 3

Bit 2

Bit 1

Bit 0

Reset
Values on
Page:

INTE

IOCIE

TMR0IF

INTF

IOCIF

Bit 7

Bit 6

Bit 5

Bit 4

GIE

PEIE

TMR0IE

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

PIE2

OSFIE

C2IE

C1IE

BCL1IE

NCO1IE

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

PIR2

OSFIF

C2IF

C1IF

BCL1IF

NCO1IF

TRISA5

TRISA4

(1)

TRISA2

TRISA1

TRISA0

114

TRISA
SSP1ADD
SSP1BUF
SSP1CON1

ADD<7:0>

235

MSSP Receive Buffer/Transmit Register

187*

WCOL

SSPOV

SSPEN

CKP

SSP1CON2

GCEN

ACKSTAT

ACKDT

ACKEN

RCEN

PEN

RSEN

SEN

233

SSP1CON3

ACKTIM

PCIE

SCIE

BOEN

SDAHT

SBCDE

AHEN

DHEN

234

SSP1MSK
SSP1STAT

Legend:
*
Note 1:

SSPM<3:0>

232

MSK<7:0>
SMP

CKE

D/A

235
S

R/W

231

= unimplemented location, read as 0. Shaded cells are not used by the MSSP module in I2C mode.
Page provides register information.
Unimplemented, read as 1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 229

PIC16(L)F1508/9
21.7

BAUD RATE GENERATOR

The MSSP module has a Baud Rate Generator available for clock generation in both I2C and SPI Master
modes. The Baud Rate Generator (BRG) reload value
is placed in the SSPxADD register (Register 21-6).
When a write occurs to SSPxBUF, the Baud Rate Generator will automatically begin counting down.
Once the given operation is complete, the internal clock
will automatically stop counting and the clock pin will
remain in its last state.

module clock line. The logic dictating when the reload

signal is asserted depends on the mode the MSSP is
being operated in.
Table 21-4 demonstrates clock rates based on
instruction cycles and the BRG value loaded into
SSPxADD.

EQUATION 21-1:
FOSC
FCLOCK = ------------------------------------------------ SSPxADD + 1 4

An internal signal Reload in Figure 21-39 triggers the

value from SSPxADD to be loaded into the BRG
counter. This occurs twice for each oscillation of the

FIGURE 21-40:

BAUD RATE GENERATOR BLOCK DIAGRAM

SSPM<3:0>

Reload

SSPxADD<7:0>

Reload

Control

SCLx

SSPxCLK

BRG Down Counter

FOSC/2

Note: Values of 0x00, 0x01 and 0x02 are not valid

for SSPxADD when used as a Baud Rate
Generator for I2C. This is an implementation
limitation.

TABLE 21-4:

Note 1:

MSSP CLOCK RATE W/BRG

FOSC

FCY

BRG Value

FCLOCK
(2 Rollovers of BRG)

16 MHz

4 MHz

09h

400 kHz(1)

16 MHz

4 MHz

0Ch

308 kHz

16 MHz

4 MHz

27h

100 kHz

4 MHz

1 MHz

09h

100 kHz

The I2C interface does not conform to the 400 kHz I2C specification (which applies to rates greater than
100 kHz) in all details, but may be used with care where higher rates are required by the application.

DS41609A-page 230

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 21-1:

SSPSTAT: SSP STATUS REGISTER

R/W-0/0

R-0/0

SMP

CKE

D/A

R/W

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

SMP: SPI Data Input Sample bit

SPI Master mode:
1 = Input data sampled at end of data output time
0 = Input data sampled at middle of data output time
SPI Slave mode:
SMP must be cleared when SPI is used in Slave mode
In I2 C Master or Slave mode:
1 = Slew rate control disabled for standard speed mode (100 kHz and 1 MHz)
0 = Slew rate control enabled for high speed mode (400 kHz)

bit 6

CKE: SPI Clock Edge Select bit (SPI mode only)

In SPI Master or Slave mode:
1 = Transmit occurs on transition from active to Idle clock state
0 = Transmit occurs on transition from Idle to active clock state
In I2 C mode only:
1 = Enable input logic so that thresholds are compliant with SMBus specification
0 = Disable SMBus specific inputs

bit 5

bit 4

D/A: Data/Address bit (I2C mode only)

1 = Indicates that the last byte received or transmitted was data
0 = Indicates that the last byte received or transmitted was address
P: Stop bit
(I2C mode only. This bit is cleared when the MSSP module is disabled, SSPEN is cleared.)
1 = Indicates that a Stop bit has been detected last (this bit is 0 on Reset)
0 = Stop bit was not detected last

bit 3

S: Start bit
(I2C mode only. This bit is cleared when the MSSP module is disabled, SSPEN is cleared.)
1 = Indicates that a Start bit has been detected last (this bit is 0 on Reset)
0 = Start bit was not detected last

bit 2

R/W: Read/Write bit information (I2C mode only)

This bit holds the R/W bit information following the last address match. This bit is only valid from the address match
to the next Start bit, Stop bit, or not ACK bit.
In I2 C Slave mode:
1 = Read
0 = Write
In I2 C Master mode:
1 = Transmit is in progress
0 = Transmit is not in progress
OR-ing this bit with SEN, RSEN, PEN, RCEN or ACKEN will indicate if the MSSP is in Idle mode.

bit 1

UA: Update Address bit (10-bit I2C mode only)

1 = Indicates that the user needs to update the address in the SSPxADD register
0 = Address does not need to be updated

bit 0

BF: Buffer Full Status bit

Receive (SPI and I2 C modes):
1 = Receive complete, SSPxBUF is full
0 = Receive not complete, SSPxBUF is empty
Transmit (I2 C mode only):
1 = Data transmit in progress (does not include the ACK and Stop bits), SSPxBUF is full
0 = Data transmit complete (does not include the ACK and Stop bits), SSPxBUF is empty

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 231

PIC16(L)F1508/9
REGISTER 21-2:

SSPXCON1: SSP CONTROL REGISTER 1

R/C/HS-0/0

R/W-0/0

WCOL

SSPOV

SSPEN

CKP

R/W-0/0

SSPM<3:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

HS = Bit is set by hardware

C = User cleared

bit 7

WCOL: Write Collision Detect bit

Master mode:
1 = A write to the SSPxBUF register was attempted while the I2C conditions were not valid for a transmission to be started
0 = No collision
Slave mode:
1 = The SSPxBUF register is written while it is still transmitting the previous word (must be cleared in software)
0 = No collision

bit 6

SSPOV: Receive Overflow Indicator bit(1)

In SPI mode:
1 = A new byte is received while the SSPxBUF register is still holding the previous data. In case of overflow, the data in SSPxSR is lost.
Overflow can only occur in Slave mode. In Slave mode, the user must read the SSPxBUF, even if only transmitting data, to avoid
setting overflow. In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated by writing to the
SSPxBUF register (must be cleared in software).
0 = No overflow
2
In I C mode:
1 = A byte is received while the SSPxBUF register is still holding the previous byte. SSPOV is a dont care in Transmit mode
(must be cleared in software).
0 = No overflow

bit 5

SSPEN: Synchronous Serial Port Enable bit

In both modes, when enabled, these pins must be properly configured as input or output
In SPI mode:
1 = Enables serial port and configures SCKx, SDOx, SDIx and SSx as the source of the serial port pins(2)
0 = Disables serial port and configures these pins as I/O port pins
In I2C mode:
1 = Enables the serial port and configures the SDAx and SCLx pins as the source of the serial port pins(3)
0 = Disables serial port and configures these pins as I/O port pins

bit 4

CKP: Clock Polarity Select bit

In SPI mode:
1 = Idle state for clock is a high level
0 = Idle state for clock is a low level
In I2C Slave mode:
SCLx release control
1 = Enable clock
0 = Holds clock low (clock stretch). (Used to ensure data setup time.)
In I2C Master mode:
Unused in this mode

bit 3-0

SSPM<3:0>: Synchronous Serial Port Mode Select bits

0000 = SPI Master mode, clock = FOSC/4
0001 = SPI Master mode, clock = FOSC/16
0010 = SPI Master mode, clock = FOSC/64
0011 = SPI Master mode, clock = TMR2 output/2
0100 = SPI Slave mode, clock = SCKx pin, SS pin control enabled
0101 = SPI Slave mode, clock = SCKx pin, SS pin control disabled, SSx can be used as I/O pin
0110 = I2C Slave mode, 7-bit address
0111 = I2C Slave mode, 10-bit address
1000 = I2C Master mode, clock = FOSC/(4 * (SSPxADD+1))(4)
1001 = Reserved
1010 = SPI Master mode, clock = FOSC/(4 * (SSPxADD+1))(5)
1011 = I2C firmware controlled Master mode (Slave idle)
1100 = Reserved
1101 = Reserved
1110 = I2C Slave mode, 7-bit address with Start and Stop bit interrupts enabled
1111 = I2C Slave mode, 10-bit address with Start and Stop bit interrupts enabled

Note

1:
2:
3:
4:
5:

In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated by writing to the SSPxBUF register.
When enabled, these pins must be properly configured as input or output.
When enabled, the SDAx and SCLx pins must be configured as inputs.
SSPxADD values of 0, 1 or 2 are not supported for I2C mode.
SSPxADD value of 0 is not supported. Use SSPM = 0000 instead.

DS41609A-page 232

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 21-3:

SSPXCON2: SSP CONTROL REGISTER 2

R/W-0/0

R-0/0

R/W-0/0

R/S/HS-0/0

R/W/HS-0/0

GCEN

ACKSTAT

ACKDT

ACKEN

RCEN

PEN

RSEN

SEN

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

HC = Cleared by hardware

S = User set

bit 7

GCEN: General Call Enable bit (in I2C Slave mode only)
1 = Enable interrupt when a general call address (0x00 or 00h) is received in the SSPxSR
0 = General call address disabled

bit 6

ACKSTAT: Acknowledge Status bit (in I2C mode only)

1 = Acknowledge was not received
0 = Acknowledge was received

bit 5

ACKDT: Acknowledge Data bit (in I2C mode only)

In Receive mode:
Value transmitted when the user initiates an Acknowledge sequence at the end of a receive
1 = Not Acknowledge
0 = Acknowledge

bit 4

ACKEN: Acknowledge Sequence Enable bit (in I2C Master mode only)
In Master Receive mode:
1 = Initiate Acknowledge sequence on SDAx and SCLx pins, and transmit ACKDT data bit.
Automatically cleared by hardware.
0 = Acknowledge sequence idle

bit 3

RCEN: Receive Enable bit (in I2C Master mode only)

1 = Enables Receive mode for I2C
0 = Receive idle

bit 2

PEN: Stop Condition Enable bit (in I2C Master mode only)
SCKx Release Control:
1 = Initiate Stop condition on SDAx and SCLx pins. Automatically cleared by hardware.
0 = Stop condition Idle

bit 1

RSEN: Repeated Start Condition Enabled bit (in I2C Master mode only)
1 = Initiate Repeated Start condition on SDAx and SCLx pins. Automatically cleared by hardware.
0 = Repeated Start condition Idle

bit 0

SEN: Start Condition Enabled bit (in I2C Master mode only)
In Master mode:
1 = Initiate Start condition on SDAx and SCLx pins. Automatically cleared by hardware.
0 = Start condition Idle
In Slave mode:
1 = Clock stretching is enabled for both slave transmit and slave receive (stretch enabled)
0 = Clock stretching is disabled

Note 1:

For bits ACKEN, RCEN, PEN, RSEN, SEN: If the I2C module is not in the Idle mode, this bit may not be
set (no spooling) and the SSPxBUF may not be written (or writes to the SSPxBUF are disabled).

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 233

PIC16(L)F1508/9
REGISTER 21-4:

SSPXCON3: SSP CONTROL REGISTER 3

R-0/0

R/W-0/0

ACKTIM

PCIE

SCIE

BOEN

SDAHT

SBCDE

AHEN

DHEN

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

ACKTIM: Acknowledge Time Status bit (I2C mode only)(3)

1 = Indicates the I2C bus is in an Acknowledge sequence, set on 8TH falling edge of SCLx clock
0 = Not an Acknowledge sequence, cleared on 9TH rising edge of SCLx clock

bit 6

PCIE: Stop Condition Interrupt Enable bit (I2C mode only)

1 = Enable interrupt on detection of Stop condition
0 = Stop detection interrupts are disabled(2)

bit 5

SCIE: Start Condition Interrupt Enable bit (I2C mode only)

1 = Enable interrupt on detection of Start or Restart conditions
0 = Start detection interrupts are disabled(2)

bit 4

BOEN: Buffer Overwrite Enable bit

In SPI Slave mode:(1)
1 = SSPxBUF updates every time that a new data byte is shifted in ignoring the BF bit
0 = If new byte is received with BF bit of the SSPxSTAT register already set, SSPOV bit of the
SSPxCON1 register is set, and the buffer is not updated
In I2C Master mode:
This bit is ignored.
In I2C Slave mode:
1 = SSPxBUF is updated and ACK is generated for a received address/data byte, ignoring the
state of the SSPOV bit only if the BF bit = 0.
0 = SSPxBUF is only updated when SSPOV is clear

bit 3

SDAHT: SDAx Hold Time Selection bit (I2C mode only)

1 = Minimum of 300 ns hold time on SDAx after the falling edge of SCLx
0 = Minimum of 100 ns hold time on SDAx after the falling edge of SCLx

bit 2

SBCDE: Slave Mode Bus Collision Detect Enable bit (I2C Slave mode only)

If on the rising edge of SCLx, SDAx is sampled low when the module is outputting a high state, the
BCLxIF bit of the PIR2 register is set, and bus goes idle
1 = Enable slave bus collision interrupts
0 = Slave bus collision interrupts are disabled
bit 1

AHEN: Address Hold Enable bit (I2C Slave mode only)

1 = Following the 8th falling edge of SCLx for a matching received address byte, CKP bit of the
SSPxCON1 register will be cleared and the SCLx will be held low.
0 = Address holding is disabled

bit 0

DHEN: Data Hold Enable bit (I2C Slave mode only)

1 = Following the 8th falling edge of SCLx for a received data byte, slave hardware clears the CKP bit
of the SSPxCON1 register and SCLx is held low.
0 = Data holding is disabled

Note 1:
2:
3:

For daisy-chained SPI operation, allows the user to ignore all but the last received byte. SSPOV is still set
when a new byte is received and BF = 1, but hardware continues to write the most recent byte to SSPxBUF.
This bit has no effect in Slave modes that Start and Stop condition detection is explicitly listed as enabled.
The ACKTIM Status bit is only active when the AHEN bit or DHEN bit is set.

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2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 21-5:
R/W-1/1

SSPXMSK: SSP MASK REGISTER

R/W-1/1

MSK<7:0>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-1

MSK<7:1>: Mask bits

1 = The received address bit n is compared to SSPxADD<n> to detect I2C address match
0 = The received address bit n is not used to detect I2C address match

bit 0

MSK<0>: Mask bit for I2C Slave mode, 10-bit Address

I2C Slave mode, 10-bit address (SSPM<3:0> = 0111 or 1111):
1 = The received address bit 0 is compared to SSPxADD<0> to detect I2C address match
0 = The received address bit 0 is not used to detect I2C address match
I2C Slave mode, 7-bit address, the bit is ignored

SSPXADD: MSSP ADDRESS AND BAUD RATE REGISTER (I2C MODE)

R/W-0/0

ADD<7:0>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

Master mode:

bit 7-0

ADD<7:0>: Baud Rate Clock Divider bits

SCLx pin clock period = ((ADD<7:0> + 1) *4)/FOSC

10-Bit Slave mode Most Significant Address Byte:

bit 7-3

Not used: Unused for Most Significant Address Byte. Bit state of this register is a dont care. Bit pattern sent by master is fixed by I2C specification and must be equal to 11110. However, those bits are
compared by hardware and are not affected by the value in this register.

bit 2-1

ADD<2:1>: Two Most Significant bits of 10-bit address

bit 0

Not used: Unused in this mode. Bit state is a dont care.

10-Bit Slave mode Least Significant Address Byte:

bit 7-0

ADD<7:0>: Eight Least Significant bits of 10-bit address

7-Bit Slave mode:

bit 7-1

ADD<7:1>: 7-bit address

bit 0

Not used: Unused in this mode. Bit state is a dont care.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 235

PIC16(L)F1508/9
NOTES:

DS41609A-page 236

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
22.0

ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)

The EUSART module includes the following capabilities:

Full-duplex asynchronous transmit and receive

Two-character input buffer
One-character output buffer
Programmable 8-bit or 9-bit character length
Address detection in 9-bit mode
Input buffer overrun error detection
Received character framing error detection
Half-duplex synchronous master
Half-duplex synchronous slave
Programmable clock polarity in synchronous
modes
Sleep operation

The Enhanced Universal Synchronous Asynchronous

Receiver Transmitter (EUSART) module is a serial I/O
communications peripheral. It contains all the clock
generators, shift registers and data buffers necessary
to perform an input or output serial data transfer
independent of device program execution. The
EUSART, also known as a Serial Communications
Interface (SCI), can be configured as a full-duplex
asynchronous system or half-duplex synchronous
system.
Full-Duplex
mode
is
useful
for
communications with peripheral systems, such as CRT
terminals and personal computers. Half-Duplex
Synchronous mode is intended for communications
with peripheral devices, such as A/D or D/A integrated
circuits, serial EEPROMs or other microcontrollers.
These devices typically do not have internal clocks for
baud rate generation and require the external clock
signal provided by a master synchronous device.

FIGURE 22-1:

The EUSART module implements the following

additional features, making it ideally suited for use in
Local Interconnect Network (LIN) bus systems:
Automatic detection and calibration of the baud rate
Wake-up on Break reception
13-bit Break character transmit
Block diagrams of the EUSART transmitter and
receiver are shown in Figure 22-1 and Figure 22-2.

EUSART TRANSMIT BLOCK DIAGRAM

Data Bus

TXIE
Interrupt

TXIF

TXREG Register
8
MSb

TX/CK pin

LSb

(8)

Pin Buffer
and Control

TRMT

SPEN

Transmit Shift Register (TSR)

TXEN
Baud Rate Generator

FOSC

TX9

BRG16
+1
SPBRGH

SPBRGL

Multiplier

x16 x64

SYNC

1 X 0 0

BRGH

X 1 1 0

BRG16

X 1 0 1

2011 Microchip Technology Inc.

TX9D

Preliminary

DS41609A-page 237

PIC16(L)F1508/9
FIGURE 22-2:

EUSART RECEIVE BLOCK DIAGRAM

SPEN

CREN

RX/DT pin

Baud Rate Generator

Data
Recovery
FOSC

SPBRGH

SPBRGL

x16 x64

SYNC

1 X 0 0

BRGH

X 1 1 0

BRG16

X 1 0 1

(8)

LSb
0 START

RX9

BRG16
Multiplier

Stop

RCIDL

RSR Register

MSb
Pin Buffer
and Control

OERR

FERR

RX9D

RCREG Register
8

FIFO

Data Bus
RCIF
RCIE

Interrupt

The operation of the EUSART module is controlled

through three registers:
Transmit Status and Control (TXSTA)
Receive Status and Control (RCSTA)
Baud Rate Control (BAUDCON)
These registers are detailed in Register 22-1,
Register 22-2 and Register 22-3, respectively.
When the receiver or transmitter section is not enabled
then the corresponding RX or TX pin may be used for
general purpose input and output.

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PIC16(L)F1508/9
22.1

EUSART Asynchronous Mode

22.1.1.2

The EUSART transmits and receives data using the

standard non-return-to-zero (NRZ) format. NRZ is
implemented with two levels: a VOH mark state which
represents a 1 data bit, and a VOL space state which
represents a 0 data bit. NRZ refers to the fact that
consecutively transmitted data bits of the same value
stay at the output level of that bit without returning to a
neutral level between each bit transmission. An NRZ
transmission port idles in the mark state. Each character
transmission consists of one Start bit followed by eight
or nine data bits and is always terminated by one or
more Stop bits. The Start bit is always a space and the
Stop bits are always marks. The most common data
format is 8 bits. Each transmitted bit persists for a period
of 1/(Baud Rate). An on-chip dedicated 8-bit/16-bit Baud
Rate Generator is used to derive standard baud rate
frequencies from the system oscillator. See Table 22-5
for examples of baud rate configurations.
The EUSART transmits and receives the LSb first. The
EUSARTs transmitter and receiver are functionally
independent, but share the same data format and baud
rate. Parity is not supported by the hardware, but can
be implemented in software and stored as the ninth
data bit.

22.1.1

EUSART ASYNCHRONOUS
TRANSMITTER

22.1.1.1

Enabling the Transmitter

The EUSART transmitter is enabled for asynchronous

operations by configuring the following three control
bits:
TXEN = 1
SYNC = 0
SPEN = 1
All other EUSART control bits are assumed to be in
their default state.
Setting the TXEN bit of the TXSTA register enables the
transmitter circuitry of the EUSART. Clearing the SYNC
bit of the TXSTA register configures the EUSART for
asynchronous operation. Setting the SPEN bit of the
RCSTA register enables the EUSART and automatically
configures the TX/CK I/O pin as an output. If the TX/CK
pin is shared with an analog peripheral, the analog I/O
function must be disabled by clearing the corresponding
ANSEL bit.
Note:

A transmission is initiated by writing a character to the

TXREG register. If this is the first character, or the
previous character has been completely flushed from
the TSR, the data in the TXREG is immediately
transferred to the TSR register. If the TSR still contains
all or part of a previous character, the new character
data is held in the TXREG until the Stop bit of the
previous character has been transmitted. The pending
character in the TXREG is then transferred to the TSR
in one TCY immediately following the Stop bit
transmission. The transmission of the Start bit, data bits
and Stop bit sequence commences immediately
following the transfer of the data to the TSR from the
TXREG.

22.1.1.3

Transmit Data Polarity

The polarity of the transmit data can be controlled with

the SCKP bit of the BAUDCON register. The default
state of this bit is 0 which selects high true transmit idle
and data bits. Setting the SCKP bit to 1 will invert the
transmit data resulting in low true idle and data bits. The
SCKP bit controls transmit data polarity in
Asynchronous mode only. In Synchronous mode, the
SCKP bit has a different function. See Section 22.4.1.2
Clock Polarity.

22.1.1.4

The EUSART transmitter block diagram is shown in

Figure 22-1. The heart of the transmitter is the serial
Transmit Shift Register (TSR), which is not directly
accessible by software. The TSR obtains its data from
the transmit buffer, which is the TXREG register.

Transmitting Data

Transmit Interrupt Flag

The TXIF interrupt flag bit of the PIR1 register is set

whenever the EUSART transmitter is enabled and no
character is being held for transmission in the TXREG.
In other words, the TXIF bit is only clear when the TSR
is busy with a character and a new character has been
queued for transmission in the TXREG. The TXIF flag bit
is not cleared immediately upon writing TXREG. TXIF
becomes valid in the second instruction cycle following
the write execution. Polling TXIF immediately following
the TXREG write will return invalid results. The TXIF bit
is read-only, it cannot be set or cleared by software.
The TXIF interrupt can be enabled by setting the TXIE
interrupt enable bit of the PIE1 register. However, the
TXIF flag bit will be set whenever the TXREG is empty,
regardless of the state of TXIE enable bit.
To use interrupts when transmitting data, set the TXIE
bit only when there is more data to send. Clear the
TXIE interrupt enable bit upon writing the last character
of the transmission to the TXREG.

The TXIF Transmitter Interrupt flag is set

when the TXEN enable bit is set.

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Preliminary

DS41609A-page 239

PIC16(L)F1508/9
22.1.1.5

TSR Status

22.1.1.7

The TRMT bit of the TXSTA register indicates the

status of the TSR register. This is a read-only bit. The
TRMT bit is set when the TSR register is empty and is
cleared when a character is transferred to the TSR
register from the TXREG. The TRMT bit remains clear
until all bits have been shifted out of the TSR register.
No interrupt logic is tied to this bit, so the user has to
poll this bit to determine the TSR status.
Note:

22.1.1.6

2.
3.

The TSR register is not mapped in data

memory, so it is not available to the user.
4.
5.

Transmitting 9-Bit Characters

The EUSART supports 9-bit character transmissions.

When the TX9 bit of the TXSTA register is set, the
EUSART will shift 9 bits out for each character transmitted. The TX9D bit of the TXSTA register is the ninth,
and Most Significant, data bit. When transmitting 9-bit
data, the TX9D data bit must be written before writing
the 8 Least Significant bits into the TXREG. All nine bits
of data will be transferred to the TSR shift register
immediately after the TXREG is written.
A special 9-bit Address mode is available for use with
multiple receivers. See Section 22.1.2.7 Address
Detection for more information on the address mode.

FIGURE 22-3:
Write to TXREG
BRG Output
(Shift Clock)

Word 1

Start bit

bit 0

bit 1

bit 7/8

Stop bit

Word 1

TXIF bit
(Transmit Buffer
Reg. Empty Flag)

FIGURE 22-4:

Initialize the SPBRGH, SPBRGL register pair and

the BRGH and BRG16 bits to achieve the desired
baud rate (see Section 22.3 EUSART Baud
Rate Generator (BRG)).
Enable the asynchronous serial port by clearing
the SYNC bit and setting the SPEN bit.
If 9-bit transmission is desired, set the TX9 control bit. A set ninth data bit will indicate that the 8
Least Significant data bits are an address when
the receiver is set for address detection.
Set SCKP bit if inverted transmit is desired.
Enable the transmission by setting the TXEN
control bit. This will cause the TXIF interrupt bit
to be set.
If interrupts are desired, set the TXIE interrupt
enable bit of the PIE1 register. An interrupt will
occur immediately provided that the GIE and
PEIE bits of the INTCON register are also set.
If 9-bit transmission is selected, the ninth bit
should be loaded into the TX9D data bit.
Load 8-bit data into the TXREG register. This
will start the transmission.

ASYNCHRONOUS TRANSMISSION

TX/CK
pin

TRMT bit
(Transmit Shift
Reg. Empty Flag)

Asynchronous Transmission Set-up:

1 TCY

Word 1
Transmit Shift Reg.

ASYNCHRONOUS TRANSMISSION (BACK-TO-BACK)

Write to TXREG
BRG Output
(Shift Clock)

Word 1

TX/CK
pin
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)

Note:

Word 2

Start bit

bit 0

1 TCY

bit 1
Word 1

bit 7/8

Stop bit

Start bit

bit 0

Word 2

1 TCY
Word 1
Transmit Shift Reg.

Word 2
Transmit Shift Reg.

This timing diagram shows two consecutive transmissions.

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Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 22-1:

SUMMARY OF REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ABDOVF

RCIDL

SCKP

BRG16

WUE

ABDEN

248

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

SPEN

RX9

SREN

CREN

ADDEN

FERR

OERR

RX9D

247*

Name

BAUDCON
INTCON

RCSTA
SPBRGL

BRG<7:0>

249*

SPBRGH

BRG<15:8>

249*

TRISC
TXREG
TXSTA

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

EUSART Transmit Data Register

CSRC

TX9

TXEN

122
239

SYNC

SENDB

BRGH

TRMT

TX9D

246

Legend: = unimplemented location, read as 0. Shaded cells are not used for asynchronous transmission.
* Page provides register information.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 241

PIC16(L)F1508/9
22.1.2

EUSART ASYNCHRONOUS
RECEIVER

22.1.2.2

The Asynchronous mode is typically used in RS-232

systems. The receiver block diagram is shown in
Figure 22-2. The data is received on the RX/DT pin and
drives the data recovery block. The data recovery block
is actually a high-speed shifter operating at 16 times
the baud rate, whereas the serial Receive Shift
Register (RSR) operates at the bit rate. When all 8 or 9
bits of the character have been shifted in, they are
immediately transferred to a two character
First-In-First-Out (FIFO) memory. The FIFO buffering
allows reception of two complete characters and the
start of a third character before software must start
servicing the EUSART receiver. The FIFO and RSR
registers are not directly accessible by software.
Access to the received data is via the RCREG register.

22.1.2.1

Enabling the Receiver

The EUSART receiver is enabled for asynchronous

operation by configuring the following three control bits:
CREN = 1
SYNC = 0
SPEN = 1
All other EUSART control bits are assumed to be in
their default state.
Setting the CREN bit of the RCSTA register enables the
receiver circuitry of the EUSART. Clearing the SYNC bit
of the TXSTA register configures the EUSART for
asynchronous operation. Setting the SPEN bit of the
RCSTA register enables the EUSART. The programmer
must set the corresponding TRIS bit to configure the
RX/DT I/O pin as an input.
Note:

If the RX/DT function is on an analog pin,

the corresponding ANSEL bit must be
cleared for the receiver to function.

Receiving Data

The receiver data recovery circuit initiates character

reception on the falling edge of the first bit. The first bit,
also known as the Start bit, is always a zero. The data
recovery circuit counts one-half bit time to the center of
the Start bit and verifies that the bit is still a zero. If it is
not a zero then the data recovery circuit aborts
character reception, without generating an error, and
resumes looking for the falling edge of the Start bit. If
the Start bit zero verification succeeds then the data
recovery circuit counts a full bit time to the center of the
next bit. The bit is then sampled by a majority detect
circuit and the resulting 0 or 1 is shifted into the RSR.
This repeats until all data bits have been sampled and
shifted into the RSR. One final bit time is measured and
the level sampled. This is the Stop bit, which is always
a 1. If the data recovery circuit samples a 0 in the
Stop bit position then a framing error is set for this
character, otherwise the framing error is cleared for this
character. See Section 22.1.2.4 Receive Framing
Error for more information on framing errors.
Immediately after all data bits and the Stop bit have
been received, the character in the RSR is transferred
to the EUSART receive FIFO and the RCIF interrupt
flag bit of the PIR1 register is set. The top character in
the FIFO is transferred out of the FIFO by reading the
RCREG register.
Note:

22.1.2.3

If the receive FIFO is overrun, no additional

characters will be received until the overrun
condition is cleared. See Section 22.1.2.5
Receive Overrun Error for more
information on overrun errors.

Receive Interrupts

The RCIF interrupt flag bit of the PIR1 register is set

whenever the EUSART receiver is enabled and there is
an unread character in the receive FIFO. The RCIF
interrupt flag bit is read-only, it cannot be set or cleared
by software.
RCIF interrupts are enabled by setting all of the
following bits:
RCIE interrupt enable bit of the PIE1 register
PEIE peripheral interrupt enable bit of the
INTCON register
GIE Global Interrupt Enable bit of the INTCON
register
The RCIF interrupt flag bit will be set when there is an
unread character in the FIFO, regardless of the state of
interrupt enable bits.

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2011 Microchip Technology Inc.

PIC16(L)F1508/9
22.1.2.4

Receive Framing Error

22.1.2.7

Each character in the receive FIFO buffer has a

corresponding framing error Status bit. A framing error
indicates that a Stop bit was not seen at the expected
time. The framing error status is accessed via the
FERR bit of the RCSTA register. The FERR bit
represents the status of the top unread character in the
receive FIFO. Therefore, the FERR bit must be read
before reading the RCREG.
The FERR bit is read-only and only applies to the top
unread character in the receive FIFO. A framing error
(FERR = 1) does not preclude reception of additional
characters. It is not necessary to clear the FERR bit.
Reading the next character from the FIFO buffer will
advance the FIFO to the next character and the next
corresponding framing error.
The FERR bit can be forced clear by clearing the SPEN
bit of the RCSTA register which resets the EUSART.
Clearing the CREN bit of the RCSTA register does not
affect the FERR bit. A framing error by itself does not
generate an interrupt.
Note:

22.1.2.5

Address Detection

A special Address Detection mode is available for use

when multiple receivers share the same transmission
line, such as in RS-485 systems. Address detection is
enabled by setting the ADDEN bit of the RCSTA
register.
Address detection requires 9-bit character reception.
When address detection is enabled, only characters
with the ninth data bit set will be transferred to the
receive FIFO buffer, thereby setting the RCIF interrupt
bit. All other characters will be ignored.
Upon receiving an address character, user software
determines if the address matches its own. Upon
address match, user software must disable address
detection by clearing the ADDEN bit before the next
Stop bit occurs. When user software detects the end of
the message, determined by the message protocol
used, software places the receiver back into the
Address Detection mode by setting the ADDEN bit.

If all receive characters in the receive

FIFO have framing errors, repeated reads
of the RCREG will not clear the FERR bit.

Receive Overrun Error

The receive FIFO buffer can hold two characters. An

overrun error will be generated if a third character, in its
entirety, is received before the FIFO is accessed. When
this happens the OERR bit of the RCSTA register is set.
The characters already in the FIFO buffer can be read
but no additional characters will be received until the
error is cleared. The error must be cleared by either
clearing the CREN bit of the RCSTA register or by
resetting the EUSART by clearing the SPEN bit of the
RCSTA register.

22.1.2.6

Receiving 9-bit Characters

The EUSART supports 9-bit character reception. When

the RX9 bit of the RCSTA register is set the EUSART
will shift 9 bits into the RSR for each character
received. The RX9D bit of the RCSTA register is the
ninth and Most Significant data bit of the top unread
character in the receive FIFO. When reading 9-bit data
from the receive FIFO buffer, the RX9D data bit must
be read before reading the 8 Least Significant bits from
the RCREG.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 243

PIC16(L)F1508/9
22.1.2.8

Asynchronous Reception Set-up:

22.1.2.9

Initialize the SPBRGH, SPBRGL register pair

and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 22.3 EUSART
Baud Rate Generator (BRG)).
2. Clear the ANSEL bit for the RX pin (if applicable).
3. Enable the serial port by setting the SPEN bit.
The SYNC bit must be clear for asynchronous
operation.
4. If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
5. If 9-bit reception is desired, set the RX9 bit.
6. Enable reception by setting the CREN bit.
7. The RCIF interrupt flag bit will be set when a
character is transferred from the RSR to the
receive buffer. An interrupt will be generated if
the RCIE interrupt enable bit was also set.
8. Read the RCSTA register to get the error flags
and, if 9-bit data reception is enabled, the ninth
data bit.
9. Get the received 8 Least Significant data bits
from the receive buffer by reading the RCREG
register.
10. If an overrun occurred, clear the OERR flag by
clearing the CREN receiver enable bit.

FIGURE 22-5:

Rcv Shift
Reg
Rcv Buffer Reg.
RCIDL

This mode would typically be used in RS-485 systems.

To set up an Asynchronous Reception with Address
Detect Enable:
1.

Initialize the SPBRGH, SPBRGL register pair

and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 22.3 EUSART
Baud Rate Generator (BRG)).
2. Clear the ANSEL bit for the RX pin (if applicable).
3. Enable the serial port by setting the SPEN bit.
The SYNC bit must be clear for asynchronous
operation.
4. If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
5. Enable 9-bit reception by setting the RX9 bit.
6. Enable address detection by setting the ADDEN
bit.
7. Enable reception by setting the CREN bit.
8. The RCIF interrupt flag bit will be set when a
character with the ninth bit set is transferred
from the RSR to the receive buffer. An interrupt
will be generated if the RCIE interrupt enable bit
was also set.
9. Read the RCSTA register to get the error flags.
The ninth data bit will always be set.
10. Get the received 8 Least Significant data bits
from the receive buffer by reading the RCREG
register. Software determines if this is the
devices address.
11. If an overrun occurred, clear the OERR flag by
clearing the CREN receiver enable bit.
12. If the device has been addressed, clear the
ADDEN bit to allow all received data into the
receive buffer and generate interrupts.

ASYNCHRONOUS RECEPTION
Start
bit
bit 0

RX/DT pin

9-bit Address Detection Mode Set-up

bit 1

bit 7/8 Stop

bit

Start
bit

bit 0

Word 1
RCREG

bit 7/8 Stop

bit

Start
bit

bit 7/8 Stop

bit

Word 2
RCREG

Read Rcv
Buffer Reg.
RCREG
RCIF
(Interrupt Flag)
OERR bit
CREN

Note:

This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word,
causing the OERR (overrun) bit to be set.

DS41609A-page 244

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 22-2:

SUMMARY OF REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ABDOVF

RCIDL

SCKP

BRG16

WUE

ABDEN

248

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

Name

BAUDCON
INTCON

RCREG
RCSTA

EUSART Receive Data Register

SPEN

RX9

SREN

SPBRGL

CREN

ADDEN

FERR

OERR

RX9D

BRG<7:0>

SPBRGH
TRISC

TRISC7

TRISC6

TXSTA

CSRC

TX9

TXEN

247*
249*

BRG<15:8>
TRISC5

82
242*

249*

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

SYNC

SENDB

BRGH

TRMT

TX9D

246

Legend: = unimplemented location, read as 0. Shaded cells are not used for asynchronous reception.
* Page provides register information.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 245

PIC16(L)F1508/9
22.2

Clock Accuracy with

Asynchronous Operation

The factory calibrates the internal oscillator block output (INTOSC). However, the INTOSC frequency may
drift as VDD or temperature changes, and this directly
affects the asynchronous baud rate. Two methods may
be used to adjust the baud rate clock, but both require
a reference clock source of some kind.

The first (preferred) method uses the OSCTUNE

register to adjust the INTOSC output. Adjusting the
value in the OSCTUNE register allows for fine resolution
changes to the system clock source. See Section 5.2.2
Internal Clock Sources for more information.
The other method adjusts the value in the Baud Rate
Generator. This can be done automatically with the
Auto-Baud Detect feature (see Section 22.3.1
Auto-Baud Detect). There may not be fine enough
resolution when adjusting the Baud Rate Generator to
compensate for a gradual change in the peripheral
clock frequency.

TXSTA: TRANSMIT STATUS AND CONTROL REGISTER

R/W-/0

R/W-0/0

R-1/1

R/W-0/0

CSRC

TX9

TXEN(1)

SYNC

SENDB

BRGH

TRMT

TX9D

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

CSRC: Clock Source Select bit

Asynchronous mode:
Dont care
Synchronous mode:
1 = Master mode (clock generated internally from BRG)
0 = Slave mode (clock from external source)

bit 6

TX9: 9-bit Transmit Enable bit

1 = Selects 9-bit transmission
0 = Selects 8-bit transmission

bit 5

TXEN: Transmit Enable bit(1)

1 = Transmit enabled
0 = Transmit disabled

bit 4

SYNC: EUSART Mode Select bit

1 = Synchronous mode
0 = Asynchronous mode

bit 3

SENDB: Send Break Character bit

Asynchronous mode:
1 = Send Sync Break on next transmission (cleared by hardware upon completion)
0 = Sync Break transmission completed
Synchronous mode:
Dont care

bit 2

BRGH: High Baud Rate Select bit

Asynchronous mode:
1 = High speed
0 = Low speed
Synchronous mode:
Unused in this mode

bit 1

TRMT: Transmit Shift Register Status bit

1 = TSR empty
0 = TSR full

bit 0

TX9D: Ninth bit of Transmit Data

Can be address/data bit or a parity bit.

Note 1:

SREN/CREN overrides TXEN in Sync mode.

DS41609A-page 246

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
RCSTA: RECEIVE STATUS AND CONTROL REGISTER(1)

R/W-0/0

R-0/0

SPEN

RX9

SREN

CREN

ADDEN

FERR

OERR

RX9D

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

SPEN: Serial Port Enable bit

1 = Serial port enabled (configures RX/DT and TX/CK pins as serial port pins)
0 = Serial port disabled (held in Reset)

bit 6

RX9: 9-bit Receive Enable bit

1 = Selects 9-bit reception
0 = Selects 8-bit reception

bit 5

SREN: Single Receive Enable bit

Asynchronous mode:
Dont care
Synchronous mode Master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode Slave
Dont care

bit 4

CREN: Continuous Receive Enable bit

Asynchronous mode:
1 = Enables receiver
0 = Disables receiver
Synchronous mode:
1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN)
0 = Disables continuous receive

bit 3

ADDEN: Address Detect Enable bit

Asynchronous mode 9-bit (RX9 = 1):
1 = Enables address detection, enable interrupt and load the receive buffer when RSR<8> is set
0 = Disables address detection, all bytes are received and ninth bit can be used as parity bit
Asynchronous mode 8-bit (RX9 = 0):
Dont care

bit 2

FERR: Framing Error bit

1 = Framing error (can be updated by reading RCREG register and receive next valid byte)
0 = No framing error

bit 1

OERR: Overrun Error bit

1 = Overrun error (can be cleared by clearing bit CREN)
0 = No overrun error

bit 0

RX9D: Ninth bit of Received Data

This can be address/data bit or a parity bit and must be calculated by user firmware.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 247

PIC16(L)F1508/9
REGISTER 22-3:

BAUDCON: BAUD RATE CONTROL REGISTER

R-0/0

R-1/1

U-0

R/W-0/0

U-0

R/W-0/0

ABDOVF

RCIDL

SCKP

BRG16

WUE

ABDEN

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

ABDOVF: Auto-Baud Detect Overflow bit

Asynchronous mode:
1 = Auto-baud timer overflowed
0 = Auto-baud timer did not overflow
Synchronous mode:
Dont care

bit 6

RCIDL: Receive Idle Flag bit

Asynchronous mode:
1 = Receiver is idle
0 = Start bit has been received and the receiver is receiving
Synchronous mode:
Dont care

bit 5

Unimplemented: Read as 0

bit 4

SCKP: Synchronous Clock Polarity Select bit

Asynchronous mode:
1 = Transmit inverted data to the TX/CK pin
0 = Transmit non-inverted data to the TX/CK pin
Synchronous mode:
1 = Data is clocked on rising edge of the clock
0 = Data is clocked on falling edge of the clock

bit 3

BRG16: 16-bit Baud Rate Generator bit

1 = 16-bit Baud Rate Generator is used
0 = 8-bit Baud Rate Generator is used

bit 2

Unimplemented: Read as 0

bit 1

WUE: Wake-up Enable bit

Asynchronous mode:
1 = Receiver is waiting for a falling edge. No character will be received, byte RCIF will be set. WUE
will automatically clear after RCIF is set.
0 = Receiver is operating normally
Synchronous mode:
Dont care

bit 0

ABDEN: Auto-Baud Detect Enable bit

Asynchronous mode:
1 = Auto-Baud Detect mode is enabled (clears when auto-baud is complete)
0 = Auto-Baud Detect mode is disabled
Synchronous mode:
Dont care

DS41609A-page 248

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
22.3

EUSART Baud Rate Generator

(BRG)

EXAMPLE 22-1:

The Baud Rate Generator (BRG) is an 8-bit or 16-bit

timer that is dedicated to the support of both the
asynchronous and synchronous EUSART operation.
By default, the BRG operates in 8-bit mode. Setting the
BRG16 bit of the BAUDCON register selects 16-bit
mode.

For a device with FOSC of 16 MHz, desired baud rate

of 9600, Asynchronous mode, 8-bit BRG:
F OS C
Desired Baud Rate = -----------------------------------------------------------------------64 [SPBRGH:SPBRGL] + 1

Solving for SPBRGH:SPBRGL:

FOSC
--------------------------------------------Desired Baud Rate
X = --------------------------------------------- 1
64

The SPBRGH, SPBRGL register pair determines the

period of the free running baud rate timer. In
Asynchronous mode the multiplier of the baud rate
period is determined by both the BRGH bit of the TXSTA
register and the BRG16 bit of the BAUDCON register. In
Synchronous mode, the BRGH bit is ignored.
Table 22-3 contains the formulas for determining the
baud rate. Example 22-1 provides a sample calculation
for determining the baud rate and baud rate error.

CALCULATING BAUD
RATE ERROR

16000000
-----------------------9600
= ------------------------ 1
64
= 25.042 = 25
16000000
Calculated Baud Rate = --------------------------64 25 + 1

Typical baud rates and error values for various

Asynchronous modes have been computed for your
convenience and are shown in Table 22-3. It may be
advantageous to use the high baud rate (BRGH = 1),
or the 16-bit BRG (BRG16 = 1) to reduce the baud rate
error. The 16-bit BRG mode is used to achieve slow
baud rates for fast oscillator frequencies.

= 9615
Calc. Baud Rate Desired Baud Rate
Error = -------------------------------------------------------------------------------------------Desired Baud Rate
9615 9600
= ---------------------------------- = 0.16%
9600

Writing a new value to the SPBRGH, SPBRGL register

pair causes the BRG timer to be reset (or cleared). This
ensures that the BRG does not wait for a timer overflow
before outputting the new baud rate.
If the system clock is changed during an active receive
operation, a receive error or data loss may result. To
avoid this problem, check the status of the RCIDL bit to
make sure that the receive operation is idle before
changing the system clock.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 249

PIC16(L)F1508/9
TABLE 22-3:

BAUD RATE FORMULAS

Configuration Bits

BRG/EUSART Mode

Baud Rate Formula

8-bit/Asynchronous

FOSC/[64 (n+1)]

8-bit/Asynchronous

16-bit/Asynchronous

8-bit/Synchronous

16-bit/Synchronous

SYNC

BRG16

BRGH

Legend:

Name

BAUDCON

SUMMARY OF REGISTERS ASSOCIATED WITH THE BAUD RATE GENERATOR

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ABDOVF

RCIDL

SCKP

BRG16

WUE

ABDEN

248

SPEN

RX9

SREN

CREN

ADDEN

FERR

OERR

RX9D

SPBRGL

BRG<7:0>

SPBRGH

BRG<15:8>

TXSTA

FOSC/[4 (n+1)]

x = Dont care, n = value of SPBRGH, SPBRGL register pair.

TABLE 22-4:

RCSTA

FOSC/[16 (n+1)]

CSRC

TX9

TXEN

SYNC

SENDB

247
249*
249*

BRGH

TRMT

TX9D

246

Legend: = unimplemented location, read as 0. Shaded cells are not used for the Baud Rate Generator.
* Page provides register information.

DS41609A-page 250

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 22-5:

BAUD RATES FOR ASYNCHRONOUS MODES

SYNC = 0, BRGH = 0, BRG16 = 0

BAUD
RATE

FOSC = 20.000 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 18.432 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 16.000 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 11.0592 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

300

1200

1221

1.73

255

1200

0.00

239

1202

0.16

207

1200

0.00

143

2400

2404

0.16

129

2400

0.00

119

2404

0.16

103

2400

0.00

9600

9470

-1.36

9600

0.00

9615

0.16

9600

0.00

10417

0.00

10286

-1.26

10417

0.00

10165

-2.42

19.2k

19.53k

1.73

19.20k

0.00

19.23k

0.16

19.20k

0.00

57.6k

57.60k

0.00

57.60k

0.00

115.2k

SYNC = 0, BRGH = 0, BRG16 = 0

BAUD
RATE

FOSC = 8.000 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 4.000 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 3.6864 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 1.000 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

300

0.16

207

300

0.00

191

300

0.16

1200

1202

0.16

103

1202

0.16

1200

0.00

1202

0.16

2400

2404

0.16

2404

0.16

2400

0.00

9600

9615

0.16

9600

0.00

10417

0.00

10417

0.00

19.2k

19.20k

0.00

57.6k

57.60k

0.00

115.2k

SYNC = 0, BRGH = 1, BRG16 = 0

BAUD
RATE

FOSC = 20.000 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 18.432 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 16.000 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

FOSC = 11.0592 MHz

Actual
Rate

%
Error

SPBRG
value
(decimal)

300

1200

2400

9600

9615

0.16

129

9600

0.00

119

9615

0.16

103

9600

0.00

10417

0.00

119

10378

-0.37

110

10417

0.00

10473

0.53

19.2k

19.23k

0.16

19.20k

0.00

19.23k

0.16

19.20k

0.00

57.6k

56.82k

-1.36

57.60k

0.00

58.82k

2.12

57.60k

0.00

115.2k

113.64k

-1.36

115.2k

0.00

111.1k

-3.55

115.2k

0.00

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 251

PIC16(L)F1508/9
TABLE 22-5:

BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)

SYNC = 0, BRGH = 1, BRG16 = 0

BAUD
RATE

FOSC = 8.000 MHz

SPBRG
Actual
%
value
Rate
Error
(decimal)

FOSC = 4.000 MHz

SPBRG
Actual
%
value
Rate
Error
(decimal)

FOSC = 3.6864 MHz

SPBRG
Actual
%
value
Rate
Error
(decimal)

FOSC = 1.000 MHz

SPBRG
Actual
%
value
Rate
Error
(decimal)

300
1200

1202

0.16

207

1200

0.00

191

300
1202

0.16
0.16

207
51

2400

2404

0.16

207

2404

0.16

103

2400

0.00

2404

0.16

9600

9615

0.16

9615

0.16

9600

0.00

10417

0.00

10417

0.00

10473

0.53

10417

0.00

19.2k

19231

0.16

19.23k

0.16

19.2k

0.00

57.6k

55556

-3.55

57.60k

0.00

115.2k

0.00

SYNC = 0, BRGH = 0, BRG16 = 1

BAUD
RATE

FOSC = 20.000 MHz

Actual
Rate

FOSC = 18.432 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

FOSC = 16.000 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

FOSC = 11.0592 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

%
Error

SPBRG
value
(decimal)

300

300.0

-0.01

4166

300.0

0.00

3839

300.03

0.01

3332

300.0

0.00

2303

1200

-0.03

1041

1200

0.00

959

1200.5

0.04

832

1200

0.00

575

2400

2399

-0.03

520

2400

0.00

479

2398

-0.08

416

2400

0.00

287

9600

9615

0.16

129

9600

0.00

119

9615

0.16

103

9600

0.00

10417

0.00

119

10378

-0.37

110

10417

0.00

10473

0.53

19.2k

19.23k

0.16

19.20k

0.00

19.23k

0.16

19.20k

0.00

57.6k

56.818

-1.36

57.60k

0.00

58.82k

2.12

57.60k

0.00

115.2k

113.636

-1.36

115.2k

0.00

111.11k

-3.55

115.2k

0.00

SYNC = 0, BRGH = 0, BRG16 = 1

BAUD
RATE

FOSC = 8.000 MHz

Actual
Rate

FOSC = 4.000 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

FOSC = 3.6864 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

FOSC = 1.000 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

%
Error

SPBRG
value
(decimal)

300

299.9

-0.02

1666

300.1

0.04

832

300.0

0.00

767

300.5

0.16

207

1200

1199

-0.08

416

1202

0.16

207

1200

0.00

191

1202

0.16

2400

2404

0.16

207

2404

0.16

103

2400

0.00

2404

0.16

9600

9615

0.16

9615

0.16

9600

0.00

10417

0.00

10417

0.00

10473

0.53

10417

0.00

19.2k

19.23k

0.16

19.23k

0.16

19.20k

0.00

57.6k

55556

-3.55

57.60k

0.00

115.2k

0.00

DS41609A-page 252

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 22-5:

BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)

SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1

FOSC = 20.000 MHz

SPBRG
Actual
%
value
Rate
Error
(decimal)

FOSC = 18.432 MHz

SPBRG
Actual
%
value
Rate
Error
(decimal)

FOSC = 16.000 MHz

SPBRG
Actual
%
value
Rate
Error
(decimal)

FOSC = 11.0592 MHz

SPBRG
Actual
%
value
Rate
Error
(decimal)

300
1200

300.0
1200

0.00
-0.01

16665
4166

300.0
1200

0.00
0.00

15359
3839

300.0
1200.1

0.00
0.01

13332
3332

300.0
1200

0.00
0.00

9215
2303

2400

0.02

2082

2400

0.00

1919

2399.5

-0.02

1666

2400

0.00

1151

9600

9597

-0.03

520

9600

0.00

479

9592

-0.08

416

9600

0.00

287

10417

0.00

479

10425

0.08

441

10417

0.00

383

10433

0.16

264

BAUD
RATE

19.2k

19.23k

0.16

259

19.20k

0.00

239

19.23k

0.16

207

19.20k

0.00

143

57.6k

57.47k

-0.22

57.60k

0.00

57.97k

0.64

57.60k

0.00

115.2k

116.3k

0.94

115.2k

0.00

114.29k

-0.79

115.2k

0.00

SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1

BAUD
RATE

FOSC = 8.000 MHz

Actual
Rate

FOSC = 4.000 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

FOSC = 3.6864 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

FOSC = 1.000 MHz

%
Error

SPBRG
value
(decimal)

Actual
Rate

%
Error

SPBRG
value
(decimal)

300

300.0

0.00

6666

300.0

0.01

3332

300.0

0.00

3071

300.1

0.04

832

1200

-0.02

1666

1200

0.04

832

1200

0.00

767

1202

0.16

207

2400

2401

0.04

832

2398

0.08

416

2400

0.00

383

2404

0.16

103

9600

9615

0.16

207

9615

0.16

103

9600

0.00

9615

0.16

10417

191

10417

0.00

10473

0.53

10417

0.00

19.2k

19.23k

0.16

103

19.23k

0.16

19.20k

0.00

19.23k

0.16

57.6k

57.14k

-0.79

58.82k

2.12

57.60k

0.00

115.2k

117.6k

2.12

111.1k

-3.55

115.2k

0.00

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 253

PIC16(L)F1508/9
22.3.1

AUTO-BAUD DETECT

The EUSART module supports automatic detection

and calibration of the baud rate.
In the Auto-Baud Detect (ABD) mode, the clock to the
BRG is reversed. Rather than the BRG clocking the
incoming RX signal, the RX signal is timing the BRG.
The Baud Rate Generator is used to time the period of
a received 55h (ASCII U) which is the Sync character
for the LIN bus. The unique feature of this character is
that it has five rising edges including the Stop bit edge.
Setting the ABDEN bit of the BAUDCON register starts
the auto-baud calibration sequence (Figure 22-6).
While the ABD sequence takes place, the EUSART
state machine is held in Idle. On the first rising edge of
the receive line, after the Start bit, the SPBRG begins
counting up using the BRG counter clock as shown in
Table 22-6. The fifth rising edge will occur on the RX pin
at the end of the eighth bit period. At that time, an
accumulated value totaling the proper BRG period is
left in the SPBRGH, SPBRGL register pair, the ABDEN
bit is automatically cleared and the RCIF interrupt flag
is set. The value in the RCREG needs to be read to
clear the RCIF interrupt. RCREG content should be
discarded. When calibrating for modes that do not use
the SPBRGH register the user can verify that the
SPBRGL register did not overflow by checking for 00h
in the SPBRGH register.
The BRG auto-baud clock is determined by the BRG16
and BRGH bits as shown in Table 22-6. During ABD,
both the SPBRGH and SPBRGL registers are used as
a 16-bit counter, independent of the BRG16 bit setting.
While calibrating the baud rate period, the SPBRGH

FIGURE 22-6:

Note 1: If the WUE bit is set with the ABDEN bit,

auto-baud detection will occur on the byte
following the Break character (see
Section 22.3.3 Auto-Wake-up on
Break).
2: It is up to the user to determine that the
incoming character baud rate is within the
range of the selected BRG clock source.
Some combinations of oscillator frequency
and EUSART baud rates are not possible.
3: During the auto-baud process, the
auto-baud counter starts counting at 1.
Upon completion of the auto-baud
sequence, to achieve maximum accuracy,
subtract 1 from the SPBRGH:SPBRGL
register pair.

TABLE 22-6:

BRG COUNTER CLOCK RATES

BRG16

BRGH

BRG Base
Clock

BRG ABD
Clock

FOSC/64

FOSC/512

FOSC/16

FOSC/128

FOSC/16

FOSC/128

FOSC/4

FOSC/32

1
Note:

During the ABD sequence, SPBRGL and

SPBRGH registers are both used as a 16-bit
counter, independent of BRG16 setting.

AUTOMATIC BAUD RATE CALIBRATION

XXXXh

BRG Value

and SPBRGL registers are clocked at 1/8th the BRG

base clock rate. The resulting byte measurement is the
average bit time when clocked at full speed.

RX pin

0000h

001Ch
Start

Edge #1
bit 1
bit 0

Edge #2
bit 3
bit 2

Edge #3
bit 5
bit 4

Edge #4
bit 7
bit 6

Edge #5
Stop bit

BRG Clock
Auto Cleared

Set by User
ABDEN bit
RCIDL
RCIF bit
(Interrupt)
Read
RCREG
SPBRGL

XXh

1Ch

SPBRGH

XXh

00h

Note 1:

The ABD sequence requires the EUSART module to be configured in Asynchronous mode.

DS41609A-page 254

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
22.3.2

AUTO-BAUD OVERFLOW

22.3.3.1

During the course of automatic baud detection, the

ABDOVF bit of the BAUDCON register will be set if the
baud rate counter overflows before the fifth rising edge
is detected on the RX pin. The ABDOVF bit indicates
that the counter has exceeded the maximum count that
can fit in the 16 bits of the SPBRGH:SPBRGL register
pair. After the ABDOVF bit has been set, the counter
continues to count until the fifth rising edge is detected
on the RX pin. Upon detecting the fifth RX edge, the
hardware will set the RCIF interrupt flag and clear the
ABDEN bit of the BAUDCON register. The RCIF flag
can be subsequently cleared by reading the RCREG
register. The ABDOVF flag of the BAUDCON register
can be cleared by software directly.
To terminate the auto-baud process before the RCIF
flag is set, clear the ABDEN bit then clear the ABDOVF
bit of the BAUDCON register. The ABDOVF bit will
remain set if the ABDEN bit is not cleared first.

22.3.3

AUTO-WAKE-UP ON BREAK

During Sleep mode, all clocks to the EUSART are

suspended. Because of this, the Baud Rate Generator
is inactive and a proper character reception cannot be
performed. The Auto-Wake-up feature allows the
controller to wake-up due to activity on the RX/DT line.
This feature is available only in Asynchronous mode.
The Auto-Wake-up feature is enabled by setting the
WUE bit of the BAUDCON register. Once set, the normal
receive sequence on RX/DT is disabled, and the
EUSART remains in an Idle state, monitoring for a
wake-up event independent of the CPU mode. A
wake-up event consists of a high-to-low transition on the
RX/DT line. (This coincides with the start of a Sync Break
or a wake-up signal character for the LIN protocol.)
The EUSART module generates an RCIF interrupt
coincident with the wake-up event. The interrupt is
generated synchronously to the Q clocks in normal CPU
operating modes (Figure 22-7), and asynchronously if
the device is in Sleep mode (Figure 22-8). The interrupt
condition is cleared by reading the RCREG register.

Special Considerations

Break Character
To avoid character errors or character fragments during
a wake-up event, the wake-up character must be all
zeros.
When the wake-up is enabled the function works
independent of the low time on the data stream. If the
WUE bit is set and a valid non-zero character is
received, the low time from the Start bit to the first rising
edge will be interpreted as the wake-up event. The
remaining bits in the character will be received as a
fragmented character and subsequent characters can
result in framing or overrun errors.
Therefore, the initial character in the transmission must
be all 0s. This must be 10 or more bit times, 13-bit
times recommended for LIN bus, or any number of bit
times for standard RS-232 devices.
Oscillator Start-up Time
Oscillator start-up time must be considered, especially
in applications using oscillators with longer start-up
intervals (i.e., LP, XT or HS/PLL mode). The Sync
Break (or wake-up signal) character must be of
sufficient length, and be followed by a sufficient
interval, to allow enough time for the selected oscillator
to start and provide proper initialization of the EUSART.
WUE Bit
The wake-up event causes a receive interrupt by
setting the RCIF bit. The WUE bit is cleared in
hardware by a rising edge on RX/DT. The interrupt
condition is then cleared in software by reading the
RCREG register and discarding its contents.
To ensure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process
before setting the WUE bit. If a receive operation is not
occurring, the WUE bit may then be set just prior to
entering the Sleep mode.

The WUE bit is automatically cleared by the low-to-high

transition on the RX line at the end of the Break. This
signals to the user that the Break event is over. At this
point, the EUSART module is in Idle mode waiting to
receive the next character.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 255

PIC16(L)F1508/9
FIGURE 22-7:

AUTO-WAKE-UP BIT (WUE) TIMING DURING NORMAL OPERATION

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1

Auto Cleared

Bit set by user

WUE bit
RX/DT Line
RCIF
Note 1:

Cleared due to User Read of RCREG

The EUSART remains in Idle while the WUE bit is set.

FIGURE 22-8:

AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP

Q1Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1Q2 Q3 Q4

Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4

OSC1
Auto Cleared

Bit Set by User

WUE bit
RX/DT Line

Note 1

RCIF
Sleep Command Executed
Note 1:
2:

Sleep Ends

Cleared due to User Read of RCREG

If the wake-up event requires long oscillator warm-up time, the automatic clearing of the WUE bit can occur while the stposc signal is
still active. This sequence should not depend on the presence of Q clocks.
The EUSART remains in Idle while the WUE bit is set.

DS41609A-page 256

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
22.3.4

BREAK CHARACTER SEQUENCE

The EUSART module has the capability of sending the

special Break character sequences that are required by
the LIN bus standard. A Break character consists of a
Start bit, followed by 12 0 bits and a Stop bit.
To send a Break character, set the SENDB and TXEN
bits of the TXSTA register. The Break character transmission is then initiated by a write to the TXREG. The
value of data written to TXREG will be ignored and all
0s will be transmitted.
The SENDB bit is automatically reset by hardware after
the corresponding Stop bit is sent. This allows the user
to preload the transmit FIFO with the next transmit byte
following the Break character (typically, the Sync
character in the LIN specification).
The TRMT bit of the TXSTA register indicates when the
transmit operation is active or idle, just as it does during
normal transmission. See Figure 22-9 for the timing of
the Break character sequence.

22.3.4.1

Break and Sync Transmit Sequence

The following sequence will start a message frame

header made up of a Break, followed by an auto-baud
Sync byte. This sequence is typical of a LIN bus
master.
1.
2.
3.
4.
5.

22.3.5

RECEIVING A BREAK CHARACTER

The Enhanced EUSART module can receive a Break

character in two ways.
The first method to detect a Break character uses the
FERR bit of the RCSTA register and the Received data
as indicated by RCREG. The Baud Rate Generator is
assumed to have been initialized to the expected baud
rate.
A Break character has been received when;
RCIF bit is set
FERR bit is set
RCREG = 00h
The second method uses the Auto-Wake-up feature
described in Section 22.3.3 Auto-Wake-up on
Break. By enabling this feature, the EUSART will
sample the next two transitions on RX/DT, cause an
RCIF interrupt, and receive the next data byte followed
by another interrupt.
Note that following a Break character, the user will
typically want to enable the Auto-Baud Detect feature.
For both methods, the user can set the ABDEN bit of
the BAUDCON register before placing the EUSART in
Sleep mode.

Configure the EUSART for the desired mode.

Set the TXEN and SENDB bits to enable the
Break sequence.
Load the TXREG with a dummy character to
initiate transmission (the value is ignored).
Write 55h to TXREG to load the Sync character
into the transmit FIFO buffer.
After the Break has been sent, the SENDB bit is
reset by hardware and the Sync character is
then transmitted.

When the TXREG becomes empty, as indicated by the

TXIF, the next data byte can be written to TXREG.

FIGURE 22-9:
Write to TXREG

SEND BREAK CHARACTER SEQUENCE

Dummy Write

BRG Output
(Shift Clock)
TX (pin)

Start bit

bit 0

bit 1

bit 11

Stop bit

Break
TXIF bit
(Transmit
Interrupt Flag)
TRMT bit
(Transmit Shift
Empty Flag)
SENDB
(send Break
control bit)

2011 Microchip Technology Inc.

SENDB Sampled Here

Preliminary

Auto Cleared

DS41609A-page 257

PIC16(L)F1508/9
22.4

EUSART Synchronous Mode

Synchronous serial communications are typically used

in systems with a single master and one or more
slaves. The master device contains the necessary circuitry for baud rate generation and supplies the clock
for all devices in the system. Slave devices can take
advantage of the master clock by eliminating the internal clock generation circuitry.
There are two signal lines in Synchronous mode: a bidirectional data line and a clock line. Slaves use the
external clock supplied by the master to shift the serial
data into and out of their respective receive and transmit shift registers. Since the data line is bidirectional,
synchronous operation is half-duplex only. Half-duplex
refers to the fact that master and slave devices can
receive and transmit data but not both simultaneously.
The EUSART can operate as either a master or slave
device.
Start and Stop bits are not used in synchronous transmissions.

22.4.1

SYNCHRONOUS MASTER MODE

Clearing the SCKP bit sets the Idle state as low. When
the SCKP bit is cleared, the data changes on the rising
edge of each clock.

22.4.1.3

Data is transferred out of the device on the RX/DT pin.

The RX/DT and TX/CK pin output drivers are automatically enabled when the EUSART is configured for synchronous master transmit operation.
A transmission is initiated by writing a character to the
TXREG register. If the TSR still contains all or part of a
previous character the new character data is held in the
TXREG until the last bit of the previous character has
been transmitted. If this is the first character, or the previous character has been completely flushed from the
TSR, the data in the TXREG is immediately transferred
to the TSR. The transmission of the character commences immediately following the transfer of the data
to the TSR from the TXREG.
Each data bit changes on the leading edge of the master clock and remains valid until the subsequent leading
clock edge.
Note:

The TSR register is not mapped in data

memory, so it is not available to the user.

22.4.1.4

Synchronous Master Transmission

Set-up:

The following bits are used to configure the EUSART

for synchronous master operation:

SYNC = 1
CSRC = 1
SREN = 0 (for transmit); SREN = 1 (for receive)
CREN = 0 (for transmit); CREN = 1 (for receive)
SPEN = 1

Setting the SYNC bit of the TXSTA register configures

the device for synchronous operation. Setting the CSRC
bit of the TXSTA register configures the device as a
master. Clearing the SREN and CREN bits of the RCSTA
register ensures that the device is in the Transmit mode,
otherwise the device will be configured to receive. Setting
the SPEN bit of the RCSTA register enables the
EUSART.

22.4.1.1

22.4.1.2

2.
3.
4.
5.
6.

Master Clock

Synchronous data transfers use a separate clock line,

which is synchronous with the data. A device configured as a master transmits the clock on the TX/CK line.
The TX/CK pin output driver is automatically enabled
when the EUSART is configured for synchronous
transmit or receive operation. Serial data bits change
on the leading edge to ensure they are valid at the trailing edge of each clock. One clock cycle is generated
for each data bit. Only as many clock cycles are generated as there are data bits.

Synchronous Master Transmission

7.
8.

Initialize the SPBRGH, SPBRGL register pair

and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 22.3 EUSART
Baud Rate Generator (BRG)).
Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
Disable Receive mode by clearing bits SREN
and CREN.
Enable Transmit mode by setting the TXEN bit.
If 9-bit transmission is desired, set the TX9 bit.
If interrupts are desired, set the TXIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
If 9-bit transmission is selected, the ninth bit
should be loaded in the TX9D bit.
Start transmission by loading data to the TXREG
register.

Clock Polarity

A clock polarity option is provided for Microwire

compatibility. Clock polarity is selected with the SCKP
bit of the BAUDCON register. Setting the SCKP bit sets
the clock Idle state as high. When the SCKP bit is set,
the data changes on the falling edge of each clock.

DS41609A-page 258

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 22-10:

SYNCHRONOUS TRANSMISSION

RX/DT
pin

bit 0

bit 1
Word 1

bit 2

bit 7

bit 0

bit 1
Word 2

bit 7

TX/CK pin
(SCKP = 0)
TX/CK pin
(SCKP = 1)
Write to
TXREG Reg

Write Word 1

Write Word 2

TXIF bit
(Interrupt Flag)
TRMT bit

TXEN bit

Note:

1
Sync Master mode, SPBRGL = 0, continuous transmission of two 8-bit words.

FIGURE 22-11:

SYNCHRONOUS TRANSMISSION (THROUGH TXEN)

RX/DT pin

bit 0

bit 2

bit 1

bit 6

bit 7

TX/CK pin
Write to
TXREG reg

TXIF bit

TRMT bit

TXEN bit

TABLE 22-7:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER

TRANSMISSION
Bit 7

Bit 6

ABDOVF
GIE

PIE1
PIR1

BAUDCON
INTCON

RCSTA

Bit 2

Bit 1

Bit 0

BRG16

WUE

ABDEN

248

IOCIE

TMR0IF

INTF

IOCIF

TXIE

SSP1IE

TMR2IE

TMR1IE

TXIF

SSP1IF

TMR2IF

TMR1IF

CREN

ADDEN

FERR

OERR

RX9D

247

Bit 5

Bit 4

Bit 3

RCIDL

SCKP

PEIE

TMR0IE

INTE

TMR1GIE

ADIE

RCIE

TMR1GIF

ADIF

RCIF

SPEN

RX9

SREN

SPBRGL

BRG<7:0>

249*

SPBRGH

BRG<15:8>

249*

TRISC

TRISC7

TRISC6

TXSTA

Legend:
*

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

EUSART Transmit Data Register

TXREG
CSRC

TX9

TXEN

SYNC

SENDB

BRGH

122
239*

TRMT

TX9D

246

= unimplemented location, read as 0. Shaded cells are not used for synchronous master transmission.
Page provides register information.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 259

PIC16(L)F1508/9
22.4.1.5

Synchronous Master Reception

Data is received at the RX/DT pin. The RX/DT pin

output driver is automatically disabled when the
EUSART is configured for synchronous master receive
operation.
In Synchronous mode, reception is enabled by setting
either the Single Receive Enable bit (SREN of the
RCSTA register) or the Continuous Receive Enable bit
(CREN of the RCSTA register).
When SREN is set and CREN is clear, only as many
clock cycles are generated as there are data bits in a
single character. The SREN bit is automatically cleared
at the completion of one character. When CREN is set,
clocks are continuously generated until CREN is
cleared. If CREN is cleared in the middle of a character
the CK clock stops immediately and the partial character is discarded. If SREN and CREN are both set, then
SREN is cleared at the completion of the first character
and CREN takes precedence.
To initiate reception, set either SREN or CREN. Data is
sampled at the RX/DT pin on the trailing edge of the
TX/CK clock pin and is shifted into the Receive Shift
Register (RSR). When a complete character is
received into the RSR, the RCIF bit is set and the character is automatically transferred to the two character
receive FIFO. The Least Significant eight bits of the top
character in the receive FIFO are available in RCREG.
The RCIF bit remains set as long as there are unread
characters in the receive FIFO.
Note:

22.4.1.6

If the RX/DT function is on an analog pin,

the corresponding ANSEL bit must be
cleared for the receiver to function.

Slave Clock

Synchronous data transfers use a separate clock line,

which is synchronous with the data. A device configured
as a slave receives the clock on the TX/CK line. The
TX/CK pin output driver is automatically disabled when
the device is configured for synchronous slave transmit
or receive operation. Serial data bits change on the
leading edge to ensure they are valid at the trailing edge
of each clock. One data bit is transferred for each clock
cycle. Only as many clock cycles should be received as
there are data bits.
Note:

22.4.1.7

If the device is configured as a slave and

the TX/CK function is on an analog pin, the
corresponding ANSEL bit must be
cleared.

buffer can be read, however, no additional characters

will be received until the error is cleared. The OERR bit
can only be cleared by clearing the overrun condition.
If the overrun error occurred when the SREN bit is set
and CREN is clear then the error is cleared by reading
RCREG. If the overrun occurred when the CREN bit is
set then the error condition is cleared by either clearing
the CREN bit of the RCSTA register or by clearing the
SPEN bit which resets the EUSART.

22.4.1.8

Receiving 9-bit Characters

The EUSART supports 9-bit character reception. When

the RX9 bit of the RCSTA register is set the EUSART
will shift 9-bits into the RSR for each character
received. The RX9D bit of the RCSTA register is the
ninth, and Most Significant, data bit of the top unread
character in the receive FIFO. When reading 9-bit data
from the receive FIFO buffer, the RX9D data bit must
be read before reading the 8 Least Significant bits from
the RCREG.

22.4.1.9

Synchronous Master Reception

Set-up:

Initialize the SPBRGH, SPBRGL register pair for

the appropriate baud rate. Set or clear the
BRGH and BRG16 bits, as required, to achieve
the desired baud rate.
2. Clear the ANSEL bit for the RX pin (if applicable).
3. Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
4. Ensure bits CREN and SREN are clear.
5. If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
6. If 9-bit reception is desired, set bit RX9.
7. Start reception by setting the SREN bit or for
continuous reception, set the CREN bit.
8. Interrupt flag bit RCIF will be set when reception
of a character is complete. An interrupt will be
generated if the enable bit RCIE was set.
9. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
10. Read the 8-bit received data by reading the
RCREG register.
11. If an overrun error occurs, clear the error by
either clearing the CREN bit of the RCSTA
register or by clearing the SPEN bit which resets
the EUSART.

Receive Overrun Error

The receive FIFO buffer can hold two characters. An

overrun error will be generated if a third character, in its
entirety, is received before RCREG is read to access
the FIFO. When this happens the OERR bit of the
RCSTA register is set. Previous data in the FIFO will
not be overwritten. The two characters in the FIFO

DS41609A-page 260

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 22-12:

SYNCHRONOUS RECEPTION (MASTER MODE, SREN)

RX/DT
pin

bit 0

bit 1

bit 2

bit 3

bit 4

bit 5

bit 6

bit 7

TX/CK pin
(SCKP = 0)
TX/CK pin
(SCKP = 1)
Write to
bit SREN
SREN bit
CREN bit 0

RCIF bit
(Interrupt)
Read
RCREG
Note:

Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0.

TABLE 22-8:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER

RECEPTION
Bit 7

Bit 6

ABDOVF
GIE

PIE1
PIR1

BAUDCON
INTCON

Bit 1

Bit 0

BRG16

WUE

ABDEN

248

IOCIE

TMR0IF

INTF

IOCIF

TXIE

SSP1IE

TMR2IE

TMR1IE

TXIF

SSP1IF

TMR2IF

TMR1IF

OERR

RX9D

Bit 4

Bit 3

RCIDL

SCKP

PEIE

TMR0IE

INTE

TMR1GIE

ADIE

RCIE

TMR1GIF

ADIF

RCIF

SPEN

RX9

SREN

RCREG
RCSTA

Bit 2

Bit 5

EUSART Receive Data Register

CREN

ADDEN

FERR

242*
247

SPBRGL

BRG<7:0>

249*

SPBRGH

BRG<15:8>

249*

TRISC

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

TXSTA

CSRC

TX9

TXEN

SYNC

SENDB

BRGH

TRMT

TX9D

246

Legend: = unimplemented location, read as 0. Shaded cells are not used for synchronous master reception.
* Page provides register information.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 261

PIC16(L)F1508/9
22.4.2

SYNCHRONOUS SLAVE MODE

The following bits are used to configure the EUSART

for synchronous slave operation:

SYNC = 1
CSRC = 0
SREN = 0 (for transmit); SREN = 1 (for receive)
CREN = 0 (for transmit); CREN = 1 (for receive)
SPEN = 1

1.
2.
3.
4.

Setting the SYNC bit of the TXSTA register configures the

device for synchronous operation. Clearing the CSRC bit
of the TXSTA register configures the device as a slave.
Clearing the SREN and CREN bits of the RCSTA register
ensures that the device is in the Transmit mode,
otherwise the device will be configured to receive. Setting
the SPEN bit of the RCSTA register enables the
EUSART.

22.4.2.1

If two words are written to the TXREG and then the

SLEEP instruction is executed, the following will occur:

EUSART Synchronous Slave

Transmit

22.4.2.2
1.

The operation of the Synchronous Master and Slave

Section 22.4.1.3
modes
are
identical
(see
Synchronous Master Transmission), except in the
case of the Sleep mode.

2.
3.
4.

5.
6.
7.
8.

TABLE 22-9:
Name

BAUDCON

The first character will immediately transfer to

the TSR register and transmit.
The second word will remain in the TXREG
register.
The TXIF bit will not be set.
After the first character has been shifted out of
TSR, the TXREG register will transfer the second
character to the TSR and the TXIF bit will now be
set.
If the PEIE and TXIE bits are set, the interrupt
will wake the device from Sleep and execute the
next instruction. If the GIE bit is also set, the
program will call the Interrupt Service Routine.

Synchronous Slave Transmission

Set-up:

Set the SYNC and SPEN bits and clear the

CSRC bit.
Clear the ANSEL bit for the CK pin (if applicable).
Clear the CREN and SREN bits.
If interrupts are desired, set the TXIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
If 9-bit transmission is desired, set the TX9 bit.
Enable transmission by setting the TXEN bit.
If 9-bit transmission is selected, insert the Most
Significant bit into the TX9D bit.
Start transmission by writing the Least
Significant 8 bits to the TXREG register.

SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE

TRANSMISSION
Bit 7

Bit 6

ABDOVF

Bit 2

Bit 1

Bit 0

BRG16

WUE

ABDEN

248

IOCIE

TMR0IF

INTF

IOCIF

78
79

Bit 5

Bit 4

Bit 3

RCIDL

SCKP
INTE

GIE

PEIE

TMR0IE

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

RCSTA

SPEN

RX9

SREN

CREN

ADDEN

FERR

OERR

RX9D

247

TRISC

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

INTCON

TXREG
TXSTA

EUSART Transmit Data Register

CSRC

TX9

TXEN

SYNC

SENDB

BRGH

239*
TRMT

TX9D

246

Legend: = unimplemented location, read as 0. Shaded cells are not used for synchronous slave transmission.
* Page provides register information.

DS41609A-page 262

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
22.4.2.3

EUSART Synchronous Slave

Reception

22.4.2.4

The operation of the Synchronous Master and Slave

modes is identical (Section 22.4.1.5 Synchronous
Master Reception), with the following exceptions:
Sleep
CREN bit is always set, therefore the receiver is
never idle
SREN bit, which is a dont care in Slave mode

1.
2.
3.

A character may be received while in Sleep mode by

setting the CREN bit prior to entering Sleep. Once the
word is received, the RSR register will transfer the data
to the RCREG register. If the RCIE enable bit is set, the
interrupt generated will wake the device from Sleep
and execute the next instruction. If the GIE bit is also
set, the program will branch to the interrupt vector.

4.
5.
6.

8.
9.

Synchronous Slave Reception

Set-up:

Set the SYNC and SPEN bits and clear the

CSRC bit.
Clear the ANSEL bit for both the CK and DT pins
(if applicable).
If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
If 9-bit reception is desired, set the RX9 bit.
Set the CREN bit to enable reception.
The RCIF bit will be set when reception is
complete. An interrupt will be generated if the
RCIE bit was set.
If 9-bit mode is enabled, retrieve the Most
Significant bit from the RX9D bit of the RCSTA
register.
Retrieve the 8 Least Significant bits from the
receive FIFO by reading the RCREG register.
If an overrun error occurs, clear the error by
either clearing the CREN bit of the RCSTA
register or by clearing the SPEN bit which resets
the EUSART.

TABLE 22-10: SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE

RECEPTION
Name

BAUDCON

Bit 7

Bit 6

ABDOVF

Bit 2

Bit 1

Bit 0

BRG16

WUE

ABDEN

248

IOCIE

TMR0IF

INTF

IOCIF

78
79

Bit 5

Bit 4

Bit 3

RCIDL

SCKP
INTE

GIE

PEIE

TMR0IE

PIE1

TMR1GIE

ADIE

RCIE

TXIE

SSP1IE

TMR2IE

TMR1IE

PIR1

TMR1GIF

ADIF

RCIF

TXIF

SSP1IF

TMR2IF

TMR1IF

INTCON

RCREG

EUSART Receive Data Register

82
242*

RCSTA

SPEN

RX9

SREN

CREN

ADDEN

FERR

OERR

RX9D

247

TRISC

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

TXSTA

CSRC

TX9

TXEN

SYNC

SENDB

BRGH

TRMT

TX9D

246

Legend: = unimplemented location, read as 0. Shaded cells are not used for synchronous slave reception.
* Page provides register information.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 263

PIC16(L)F1508/9
22.5

EUSART Operation During Sleep

The EUSART will remain active during Sleep only in the

Synchronous Slave mode. All other modes require the
system clock and therefore cannot generate the necessary signals to run the Transmit or Receive Shift registers during Sleep.
Synchronous Slave mode uses an externally generated
clock to run the Transmit and Receive Shift registers.

22.5.1

SYNCHRONOUS RECEIVE DURING

SLEEP

To receive during Sleep, all the following conditions

must be met before entering Sleep mode:
RCSTA and TXSTA Control registers must be
configured for Synchronous Slave Reception (see
Section 22.4.2.4 Synchronous Slave
Reception Set-up:).
If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
The RCIF interrupt flag must be cleared by reading RCREG to unload any pending characters in
the receive buffer.
Upon entering Sleep mode, the device will be ready to
accept data and clocks on the RX/DT and TX/CK pins,
respectively. When the data word has been completely
clocked in by the external device, the RCIF interrupt
flag bit of the PIR1 register will be set. Thereby, waking
the processor from Sleep.
Upon waking from Sleep, the instruction following the
SLEEP instruction will be executed. If the Global Interrupt Enable (GIE) bit of the INTCON register is also set,
then the Interrupt Service Routine at address 004h will
be called.

DS41609A-page 264

22.5.2

SYNCHRONOUS TRANSMIT
DURING SLEEP

To transmit during Sleep, all the following conditions

must be met before entering Sleep mode:
RCSTA and TXSTA Control registers must be
configured for synchronous slave transmission
(see Section 22.4.2.2 Synchronous Slave
Transmission Set-up:).
The TXIF interrupt flag must be cleared by writing
the output data to the TXREG, thereby filling the
TSR and transmit buffer.
If interrupts are desired, set the TXIE bit of the
PIE1 register and the PEIE bit of the INTCON register.
Interrupt enable bits TXIE of the PIE1 register and
PEIE of the INTCON register must set.
Upon entering Sleep mode, the device will be ready to
accept clocks on TX/CK pin and transmit data on the
RX/DT pin. When the data word in the TSR has been
completely clocked out by the external device, the
pending byte in the TXREG will transfer to the TSR and
the TXIF flag will be set. Thereby, waking the processor
from Sleep. At this point, the TXREG is available to
accept another character for transmission, which will
clear the TXIF flag.
Upon waking from Sleep, the instruction following the
SLEEP instruction will be executed. If the Global
Interrupt Enable (GIE) bit is also set then the Interrupt
Service Routine at address 0004h will be called.

22.5.3

ALTERNATE PIN LOCATIONS

This module incorporates I/O pins that can be moved to

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
23.0

PULSE WIDTH MODULATION

(PWM) MODULE

For a step-by-step procedure on how to set up this

module for PWM operation, refer to Section 23.1.9
Setup for PWM Operation using PWMx Pins.

The PWM module generates a Pulse-Width Modulated

signal determined by the duty cycle, period, and resolution that are configured by the following registers:

FIGURE 23-1:

PWM OUTPUT

Period

PR2
T2CON
PWMxDCH
PWMxDCL
PWMxCON

Pulse Width

TMR2 = 0

TMR2 = PR2
TMR2 =
PWMxDCH<7:0>:PWMxDCL<7:6>

Figure 23-2 shows a simplified block diagram of PWM

operation.
Figure 23-1 shows a typical waveform of the PWM
signal.

FIGURE 23-2:

SIMPLIFIED PWM BLOCK DIAGRAM

Duty Cycle registers

PWMxDCL<7:6>

PWMxDCH
PWMxOUT
to other peripherals: CLC and CWG
Latched
(Not visible to user)

Output Enable (PWMxOE)

TRIS Control
Comparator

0
PWMx

TMR2 Module

TMR2

Output Polarity (PWMxPOL)

(1)

Comparator

PR2

Note 1:

Clear Timer,
PWMx pin and
latch Duty Cycle

8-bit timer is concatenated with the two Least Significant bits of 1/FOSC adjusted by
the Timer2 prescaler to create a 10-bit time base.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 265

PIC16(L)F1508/9
23.1

PWMx Pin Configuration

All PWM outputs are multiplexed with the PORT data

latch. The user must configure the pins as outputs by
clearing the associated TRIS bits.
Note:

23.1.1

Clearing the PWMxOE bit will relinquish

control of the PWMx pin.

FUNDAMENTAL OPERATION

The PWM module produces a 10-bit resolution output.

Timer2 and PR2 set the period of the PWM. The
PWMxDCL and PWMxDCH registers configure the
duty cycle. The period is common to all PWM modules,
whereas the duty cycle is independently controlled.
Note:

The Timer2 postscaler is not used in the

determination of the PWM frequency. The
postscaler could be used to have a servo
update rate at a different frequency than
the PWM output.

All PWM outputs associated with Timer2 are set when

TMR2 is cleared. Each PWMx is cleared when TMR2
is equal to the value specified in the corresponding
PWMxDCH (8 MSb) and PWMxDCL<7:6> (2 LSb) registers. When the value is greater than or equal to PR2,
the PWM output is never cleared (100% duty cycle).
Note:

23.1.2

When TMR2 is equal to PR2, the following three events

occur on the next increment cycle:
TMR2 is cleared
The PWM output is active. (Exception: When the
PWM duty cycle = 0%, the PWM output will
remain inactive.)
The PWMxDCH and PWMxDCL register values
are latched into the buffers.
Note:

23.1.4

Equation 23-2 is used to calculate the PWM pulse

width.
Equation 23-3 is used to calculate the PWM duty cycle
ratio.

EQUATION 23-2:

T OS C (TMR2 Prescale Value)

Note: TOSC = 1/FOSC

EQUATION 23-3:

EQUATION 23-1:

PWM PERIOD

DUTY CYCLE RATIO

PWMxDCH:PWMxDCL<7:6>
Duty Cycle Ratio = ----------------------------------------------------------------------------------4 PR2 + 1

PWM PERIOD

The PWM period is specified by the PR2 register of

Timer2. The PWM period can be calculated using the
formula of Equation 23-1.

PULSE WIDTH

Pulse Width = PWMxDCH:PWMxDCL<7:6>

The output polarity is inverted by setting the PWMxPOL

bit of the PWMxCON register.

23.1.3

PWM DUTY CYCLE

The PWM duty cycle is specified by writing a 10-bit

value to the PWMxDCH and PWMxDCL register pair.
The PWMxDCH register contains the eight MSbs and
the PWMxDCL<7:6>, the two LSbs. The PWMxDCH
and PWMxDCL registers can be written to at any time.

The PWMxDCH and PWMxDCL registers

are double buffered. The buffers are
updated when Timer2 matches PR2. Care
should be taken to update both registers
before the timer match occurs.

PWM OUTPUT POLARITY

The Timer2 postscaler has no effect on

the PWM operation.

The 8-bit timer TMR2 register is concatenated with the

two Least Significant bits of 1/FOSC, adjusted by the
Timer2 prescaler to create the 10-bit time base. The
system clock is used if the Timer2 prescaler is set to
1:1.

PWM Period = PR2 + 1 4 T OSC

(TMR2 Prescale Value)
Note:

TOSC = 1/FOSC

DS41609A-page 266

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
23.1.5

PWM RESOLUTION

The resolution determines the number of available duty

cycles for a given period. For example, a 10-bit resolution will result in 1024 discrete duty cycles, whereas an
8-bit resolution will result in 256 discrete duty cycles.
The maximum PWM resolution is 10 bits when PR2 is
255. The resolution is a function of the PR2 register
value as shown by Equation 23-4.

EQUATION 23-4:

PWM RESOLUTION

log 4 PR2 + 1
Resolution = ------------------------------------------ bits
log 2

Note:

If the pulse width value is greater than the

period the assigned PWM pin(s) will
remain unchanged.

TABLE 23-1:

EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz)

PWM Frequency

0.31 kHz

Timer Prescale (1, 4, 64)

PR2 Value

78.12 kHz

156.3 kHz

208.3 kHz

0xFF

0x3F

0x1F

0x17

6.6

EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 8 MHz)

PWM Frequency

0.31 kHz

Timer Prescale (1, 4, 64)

PR2 Value

4.90 kHz

19.61 kHz

76.92 kHz

153.85 kHz

200.0 kHz

0x65

0x19

0x0C

0x09

Maximum Resolution (bits)

23.1.6

19.53 kHz

0xFF

Maximum Resolution (bits)

TABLE 23-2:

4.88 kHz

OPERATION IN SLEEP MODE

In Sleep mode, the TMR2 register will not increment

and the state of the module will not change. If the
PWMx pin is driving a value, it will continue to drive that
value. When the device wakes up, TMR2 will continue
from its previous state.

23.1.7

CHANGES IN SYSTEM CLOCK

FREQUENCY

The PWM frequency is derived from the system clock

frequency (FOSC). Any changes in the system clock frequency will result in changes to the PWM frequency.
Refer to Section 5.0 Oscillator Module (With
Fail-Safe Clock Monitor) for additional details.

23.1.8

EFFECTS OF RESET

Any Reset will force all ports to Input mode and the
PWM registers to their Reset states.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 267

PIC16(L)F1508/9
23.1.9

SETUP FOR PWM OPERATION

USING PWMx PINS

The following steps should be taken when configuring

the module for PWM operation using the PWMx pins:
1.
2.
3.
4.
5.

Disable the PWMx pin output driver(s) by setting

the associated TRIS bit(s).
Clear the PWMxCON register.
Load the PR2 register with the PWM period
value.
Clear the PWMxDCH register and bits <7:6> of
the PWMxDCL register.
Configure and start Timer2:
Clear the TMR2IF interrupt flag bit of the
PIR1 register. See Note below.
Configure the T2CKPS bits of the T2CON
register with the Timer2 prescale value.
Enable Timer2 by setting the TMR2ON bit of
the T2CON register.
Enable PWM output pin and wait until Timer2
overflows, TMR2IF bit of the PIR1 register is set.
See note below.
Enable the PWMx pin output driver(s) by clearing the associated TRIS bit(s) and setting the
PWMxOE bit of the PWMxCON register.
Configure the PWM module by loading the
PWMxCON register with the appropriate values.
Note 1: In order to send a complete duty cycle
and period on the first PWM output, the
above steps must be followed in the order
given. If it is not critical to start with a
complete PWM signal, then move Step 8
to replace Step 4.
2: For operation with other peripherals only,
disable PWMx pin outputs.

DS41609A-page 268

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
23.2

PWM Register Definitions

PWMxCON: PWM CONTROL REGISTER

R/W-0/0

R-0/0

R/W-0/0

U-0

PWMxEN

PWMxOE

PWMxOUT

PWMxPOL

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

PWMxEN: PWM Module Enable bit

1 = PWM module is enabled
0 = PWM module is disabled

bit 6

PWMxOE: PWM Module Output Enable bit

1 = Output to PWMx pin is enabled
0 = Output to PWMx pin is disabled

bit 5

PWMxOUT: PWM Module Output Value bit

bit 4

PWMxPOL: PWMx Output Polarity Select bit

1 = PWM output is active low
0 = PWM output is active high

bit 3-0

Unimplemented: Read as 0

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 269

PIC16(L)F1508/9
REGISTER 23-2:
R/W-x/u

PWMxDCH: PWM DUTY CYCLE HIGH BITS

R/W-x/u

PWMxDCH<7:0>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

PWMxDCH<7:0>: PWM Duty Cycle Most Significant bits

These bits are the MSbs of the PWM duty cycle. The two LSbs are found in the PWMxDCL register.

PWMxDCL: PWM DUTY CYCLE LOW BITS

R/W-x/u

PWMxDCL<7:6>

U-0

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-6

PWMxDCL<7:6>: PWM Duty Cycle Least Significant bits

These bits are the LSbs of the PWM duty cycle. The MSbs are found in the PWMxDCH register.

bit 5-0

Unimplemented: Read as 0

TABLE 23-3:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH PWM

Bit 7

Bit 6

Bit 5

PWM1EN

PWM1OE

PWM1OUT

PR2

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Timer2 module Period Register

PWM1CON
PWM1DCH
PWM1DCL
PWM2CON

PWM3CON

PWM1DCL<7:6>
PWM2EN

PWM2OE

PWM4CON

179*

PWM2POL

PWM2DCH<7:0>
PWM2DCL<7:6>
PWM3EN

PWM3OE

PWM3DCL<7:6>
PWM4OE

PWM3OUT

PWM3POL

PWM4POL

PWM4DCH<7:0>

PWM4DCL

PWM4DCL<7:6>

T2CON

T2OUTPS<3:0>

TMR2

270
270
269
270

PWM4OUT

PWM4DCH

270
270

PWM3DCH<7:0>
PWM4EN

269
270

PWM2OUT

PWM3DCH
PWM3DCL

PWM1DCH<7:0>

PWM2DCH
PWM2DCL

PWM1POL

270
269
270

TMR2ON

T2CKPS<1:0>

Timer2 module Register

270
181
179*

TRISA

TRISA5

TRISA4

(1)

TRISA2

TRISA1

TRISA0

114

TRISC

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

Legend:
Note

*
1:

- = Unimplemented locations, read as 0, u = unchanged, x = unknown. Shaded cells are not used by the PWM.
Page provides register information.
Unimplemented, read as 1.

DS41609A-page 270

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
24.0

CONFIGURABLE LOGIC CELL

(CLC)

The Configurable Logic Cell (CLCx) provides programmable logic that operates outside the speed limitations
of software execution. The logic cell takes up to 16
input signals and through the use of configurable gates
reduces the 16 inputs to four logic lines that drive one
of eight selectable single-output logic functions.
Input sources are a combination of the following:

I/O pins
Internal clocks
Peripherals
Register bits

The output can be directed internally to peripherals and

to an output pin.

CLCxIN[0]
CLCxIN[1]
CLCxIN[2]
CLCxIN[3]
CLCxIN[4]
CLCxIN[5]
CLCxIN[6]
CLCxIN[7]
CLCxIN[8]
CLCxIN[9]
CLCxIN[10]
CLCxIN[11]
CLCxIN[12]
CLCxIN[13]
CLCxIN[14]
CLCxIN[15]

Possible configurations include:

Combinatorial Logic
- AND
- NAND
- AND-OR
- AND-OR-INVERT
- OR-XOR
- OR-XNOR
Latches
- S-R
- Clocked D with Set and Reset
- Transparent D with Set and Reset
- Clocked J-K with Reset

CLCx SIMPLIFIED BLOCK DIAGRAM

D
Q1

See Figure 24-3

Input Data Selection Gates

FIGURE 24-1:

Refer to Figure 24-1 for a simplified diagram showing

signal flow through the CLCx.

MLCxOUT

LCxOE

LCxEN

lcxg1

LCxOUT

TRIS Control

lcxg2

Logic

lcxg3

Function

lcxq

lcx_out

CLCx

lcxg4
LCxPOL
LCxMODE<2:0>

det
LCxINTP
LCxINTN

sets
CLCxIF
flag

Interrupt

See Figure 24-2

2011 Microchip Technology Inc.

Interrupt

det

Preliminary

DS41609A-page 271

PIC16(L)F1508/9
24.1

CLCx Setup

24.1.1

Programming the CLCx module is performed by configuring the 4 stages in the logic signal flow. The 4 stages
are:

Data selection
Data gating
Logic function selection
Output polarity

Each stage is setup at run time by writing to the corresponding CLCx Special Function Registers. This has
the added advantage of permitting logic reconfiguration
on-the-fly during program execution.

DATA SELECTION

There are 16 signals available as inputs to the configurable logic. Four 8-input multiplexers are used to select
the inputs to pass on to the next stage. The 16 inputs to
the multiplexers are arranged in groups of four. Each
group is available to two of the four multiplexers, in
each case, paired with a different group. This arrangement makes possible selection of up to two from a
group without precluding a selection from another
group.
Data inputs are selected with the CLCxSEL0 and
CLCxSEL1 registers (Register 24-3 and Register 24-4,
respectively).
Data inputs are selected with CLCxSEL0 and
CLCxSEL1 registers (Register 24-3 and Register 24-4,
respectively).
Data selection is through four multiplexers as indicated
on the left side of Figure 24-2. Data inputs in the figure
are identified by a generic numbered input name.
Table 24-1 correlates the generic input name to the
actual signal for each CLC module. The columns labeled
lcxd1 through lcxd4 indicate the MUX output for the
selected data input. D1S through D4S are abbreviations
for the MUX select input codes: LCxD1S<2:0> through
LCxD4S<2:0>, respectively. Selecting a data input in a
column excludes all other inputs in that column.
Note:

TABLE 24-1:
Data Input

Data selections are undefined at power-up.

CLCx DATA INPUT SELECTION

lcxd1
D1S

lcxd2
D2S

lcxd3
D3S

lcxd4
D4S

CLC 1

CLC 2

CLC 3

CLC 4

CLCxIN[0]

000

100

CLC1IN0

CLC2IN0

CLC3IN0

CLC4IN0

CLCxIN[1]

001

101

CLC1IN1

CLC2IN1

CLC3IN1

CLC4IN1

CLCxIN[2]

010

110

SYNCC1OUT

CLCxIN[3]

011

111

SYNCC2OUT

CLCxIN[4]

100

000

FOSC

CLCxIN[5]

101

001

TMR0IF

CLCxIN[6]

110

010

TMR1IF

CLCxIN[7]

111

011

TMR2 = PR2

CLCxIN[8]

100

000

lc1_out

CLCxIN[9]

101

001

lc2_out

CLCxIN[10]

110

010

lc3_out

CLCxIN[11]

111

011

lc4_out

CLCxIN[12]

100

000

NCO1OUT

LFINTOSC

TX (EUSART)

SCK (MSSP)

CLCxIN[13]

101

001

HFINTOSC

ADFRC

LFINTOSC

SDO (MSSP)

CLCxIN[14]

110

010

PWM3OUT

PWM1OUT

PWM2OUT

PWM1OUT

CLCxIN[15]

111

011

PWM4OUT

PWM2OUT

PWM3OUT

PWM4OUT

DS41609A-page 272

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
24.1.2

DATA GATING

Outputs from the input multiplexers are directed to the

desired logic function input through the data gating
stage. Each data gate can direct any combination of the
four selected inputs.
Note:

24.1.3

Data gating is undefined at power-up.

The gate stage is more than just signal direction. The

gate can be configured to direct each input signal as
inverted or non-inverted data. Directed signals are
ANDed together in each gate. The output of each gate
can be inverted before going on to the logic function
stage.
The gating is in essence a 1-to-4 input
AND/NAND/OR/NOR gate. When every input is
inverted and the output is inverted, the gate is an OR of
all enabled data inputs. When the inputs and output are
not inverted, the gate is an AND or all enabled inputs.
Table 24-2 summarizes the basic logic that can be
obtained in gate 1 by using the gate logic select bits.
The table shows the logic of four input variables, but
each gate can be configured to use less than four. If
no inputs are selected, the output will be zero or one,
depending on the gate output polarity bit.

TABLE 24-2:

LCxG1POL

Gate Logic

0x55

AND

0x55

NAND

0xAA

NOR

0xAA

0x00

Logic 0

0x00

Logic 1

LOGIC FUNCTION

There are 8 available logic functions including:

AND-OR
OR-XOR
AND
S-R Latch
D Flip-Flop with Set and Reset
D Flip-Flop with Reset
J-K Flip-Flop with Reset
Transparent Latch with Set and Reset

Logic functions are shown in Figure 24-3. Each logic

function has four inputs and one output. The four inputs
are the four data gate outputs of the previous stage.
The output is fed to the inversion stage and from there
to other peripherals, an output pin, and back to the
CLCx itself.

24.1.4

OUTPUT POLARITY

The last stage in the configurable logic cell is the output

polarity. Setting the LCxPOL bit of the CLCxCON register inverts the output signal from the logic stage.
Changing the polarity while the interrupts are enabled
will cause an interrupt for the resulting output transition.

DATA GATING LOGIC

CLCxGLS0

Data gating is indicated in the right side of Figure 24-2.

Only one gate is shown in detail. The remaining three
gates are configured identically with the exception that
the data enables correspond to the enables for that
gate.

It is possible (but not recommended) to select both the

true and negated values of an input. When this is done,
the gate output is zero, regardless of the other inputs,
but may emit logic glitches (transient-induced pulses).
If the output of the channel must be zero or one, the
recommended method is to set all gate bits to zero and
use the gate polarity bit to set the desired level.
Data gating is configured with the logic gate select registers as follows:

Gate 1: CLCxGLS0 (Register 24-5)

Gate 2: CLCxGLS1 (Register 24-6)
Gate 3: CLCxGLS2 (Register 24-7)
Gate 4: CLCxGLS3 (Register 24-8)

Register number suffixes are different than the gate

numbers because other variations of this module have
multiple gate selections in the same register.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 273

PIC16(L)F1508/9
24.1.5

24.2

CLCx SETUP STEPS

The following steps should be followed when setting up

the CLCx:
Disable CLCx by clearing the LCxEN bit.
Select desired inputs using CLCxSEL0 and
CLCxSEL1 registers (See Table 24-1).
Clear any associated ANSEL bits.
Set all TRIS bits associated with inputs.
Clear all TRIS bits associated with outputs.
Enable the chosen inputs through the four gates
using CLCxGLS0, CLCxGLS1, CLCxGLS2, and
CLCxGLS3 registers.
Select the gate output polarities with the
LCxPOLy bits of the CLCxPOL register.
Select the desired logic function with the
LCxMODE<2:0> bits of the CLCxCON register.
Select the desired polarity of the logic output with
the LCxPOL bit of the CLCxPOL register. (This
step may be combined with the previous gate output polarity step).
If driving the CLCx pin, set the LCxOE bit of the
CLCxCON register and also clear the TRIS bit
corresponding to that output.
If interrupts are desired, configure the following
bits:
- Set the LCxINTP bit in the CLCxCON register
for rising event.
- Set the LCxINTN bit in the CLCxCON
register or falling event.
- Set the CLCxIE bit of the associated PIE
registers.
- Set the GIE and PEIE bits of the INTCON
register.
Enable the CLCx by setting the LCxEN bit of the
CLCxCON register.

CLCx Interrupts

An interrupt will be generated upon a change in the

output value of the CLCx when the appropriate interrupt
enables are set. A rising edge detector and a falling
edge detector are present in each CLC for this purpose.
The CLCxIF bit of the associated PIR registers will be
set when either edge detector is triggered and its associated enable bit is set. The LCxINTP enables rising
edge interrupts and the LCxINTN bit enables falling
edge interrupts. Both are located in the CLCxCON register.
To fully enable the interrupt, set the following bits:
LCxON bit of the CLCxCON register
CLCxIE bit of the associated PIE registers
LCxINTP bit of the CLCxCON register (for a rising
edge detection)
LCxINTN bit of the CLCxCON register (for a falling edge detection)
PEIE and GIE bits of the INTCON register
The CLCxIF bit of the associated PIR registers, must
be cleared in software as part of the interrupt service. If
another edge is detected while this flag is being
cleared, the flag will still be set at the end of the
sequence.

24.3

Output Mirror Copies

Mirror copies of all LCxCON output bits are contained

in the CLCxDATA register. Reading this register reads
the outputs of all CLCs simultaneously. This prevents
any reading skew introduced by testing or reading the
CLCxOUT bits in the individual CLCxCON registers.

24.4

Effects of a Reset

The CLCxCON register is cleared to zero as the result

of a Reset. All other selection and gating values remain
unchanged.

24.5

Operation During Sleep

The CLC module operates independently from the

system clock and will continue to run during Sleep,
provided that the input sources selected remain active.
The HFINTOSC remains active during Sleep when the
CLC module is enabled and the HFINTOSC is
selected as an input source, regardless of the system
clock source selected.
In other words, if the HFINTOSC is simultaneously
selected as the system clock and as a CLC input
source, when the CLC is enabled, the CPU will go idle
during Sleep, but the CLC will continue to operate and
the HFINTOSC will remain active.
This will have a direct effect on the Sleep mode current.

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Preliminary

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PIC16(L)F1508/9
FIGURE 24-2:

CLCxIN[0]
CLCxIN[1]
CLCxIN[2]
CLCxIN[3]
CLCxIN[4]
CLCxIN[5]
CLCxIN[6]
CLCxIN[7]

INPUT DATA SELECTION AND GATING

Data Selection

000

Data GATE 1
lcxd1T

LCxD1G1T

lcxd1N

LCxD1G1N

111

LCxD2G1T

LCxD1S<2:0>

LCxD2G1N
CLCxIN[4]
CLCxIN[5]
CLCxIN[6]
CLCxIN[7]
CLCxIN[8]
CLCxIN[9]
CLCxIN[10]
CLCxIN[11]

lcxg1

000

LCxD3G1T
lcxd2T

LCxG1POL

LCxD3G1N

lcxd2N
LCxD4G1T
111

LCxD2S<2:0>
CLCxIN[8]
CLCxIN[9]
CLCxIN[10]
CLCxIN[11]
CLCxIN[12]
CLCxIN[13]
CLCxIN[14]
CLCxIN[15]

LCxD4G1N

000

Data GATE 2
lcxg2
lcxd3T

(Same as Data GATE 1)

lcxd3N
Data GATE 3
111

lcxg3
LCxD3S<2:0>

CLCxIN[12]
CLCxIN[13]
CLCxIN[14]
CLCxIN[15]
CLCxIN[0]
CLCxIN[1]
CLCxIN[2]
CLCxIN[3]

(Same as Data GATE 1)

Data GATE 4

000

lcxg4
(Same as Data GATE 1)

lcxd4T
lcxd4N
111

LCxD4S<2:0>

Note:

All controls are undefined at power-up.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 275

PIC16(L)F1508/9
FIGURE 24-3:

PROGRAMMABLE LOGIC FUNCTIONS

AND OR

OR XOR

lcxg1

lcxg2

lcxq

lcxg3

lcxq

lcxg3

lcxg4

lcxg4
LCxMODE<2:0>= 000

LCxMODE<2:0>= 001

4-Input AND

S-R Latch

lcxg1

lcxg2

lcxq

lcxg3

lcxg4

LCxMODE<2:0>= 010

lcxq

LCxMODE<2:0>= 011

1-Input D Flip-Flop with S and R

2-Input D Flip-Flop with R

lcxg4
lcxg2

lcxg4
Q

lcxq

lcxg2
lcxg1

lcxg1

lcxq

R
lcxg3

lcxg3
LCxMODE<2:0>= 100

LCxMODE<2:0>= 101

J-K Flip-Flop with R

1-Input Transparent Latch with S and R

lcxg4
lcxg2

lcxq

lcxg1
lcxg4

lcxg2

lcxg1

lcxg3

lcxq

lcxg3
LCxMODE<2:0>= 110

DS41609A-page 276

LCxMODE<2:0>= 111

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
24.6

CLCx Control Registers

CLCxCON: CONFIGURABLE LOGIC CELL CONTROL REGISTER

R/W-0/0

R-0/0

R/W-0/0

LCxEN

LCxOE

LCxOUT

LCxINTP

LCxINTN

R/W-0/0

LCxMODE<2:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

LCxEN: Configurable Logic Cell Enable bit

1 = Configurable logic cell is enabled and mixing input signals
0 = Configurable logic cell is disabled and has logic zero output

bit 6

LCxOE: Configurable Logic Cell Output Enable bit

1 = Configurable logic cell port pin output enabled
0 = Configurable logic cell port pin output disabled

bit 5

LCxOUT: Configurable Logic Cell Data Output bit

Read-only: logic cell output data, after LCxPOL; sampled from lcx_out wire.

bit 4

LCxINTP: Configurable Logic Cell Positive Edge Going Interrupt Enable bit
1 = CLCxIF will be set when a rising edge occurs on lcx_out
0 = CLCxIF will not be set

bit 3

LCxINTN: Configurable Logic Cell Negative Edge Going Interrupt Enable bit
1 = CLCxIF will be set when a falling edge occurs on lcx_out
0 = CLCxIF will not be set

bit 2-0

LCxMODE<2:0>: Configurable Logic Cell Functional Mode bits

111 = Cell is 1-input transparent latch with S and R
110 = Cell is J-K flip-flop with R
101 = Cell is 2-input D flip-flop with R
100 = Cell is 1-input D flip-flop with S and R
011 = Cell is S-R latch
010 = Cell is 4-input AND
001 = Cell is OR-XOR
000 = Cell is AND-OR

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Preliminary

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PIC16(L)F1508/9
REGISTER 24-2:

CLCxPOL: SIGNAL POLARITY CONTROL REGISTER

R/W-0/0

U-0

R/W-x/u

LCxPOL

LCxG4POL

LCxG3POL

LCxG2POL

LCxG1POL

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

LCxPOL: LCOUT Polarity Control bit

1 = The output of the logic cell is inverted
0 = The output of the logic cell is not inverted

bit 6-4

Unimplemented: Read as 0

bit 3

LCxG4POL: Gate 4 Output Polarity Control bit

1 = The output of gate 4 is inverted when applied to the logic cell
0 = The output of gate 4 is not inverted

bit 2

LCxG3POL: Gate 3 Output Polarity Control bit

1 = The output of gate 3 is inverted when applied to the logic cell
0 = The output of gate 3 is not inverted

bit 1

LCxG2POL: Gate 2 Output Polarity Control bit

1 = The output of gate 2 is inverted when applied to the logic cell
0 = The output of gate 2 is not inverted

bit 0

LCxG1POL: Gate 1 Output Polarity Control bit

1 = The output of gate 1 is inverted when applied to the logic cell
0 = The output of gate 1 is not inverted

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PIC16(L)F1508/9
REGISTER 24-3:
U-0

CLCxSEL0: MULTIPLEXER DATA 1 AND 2 SELECT REGISTER

R/W-x/u

LCxD2S<2:0>

U-0

R/W-x/u

LCxD1S<2:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

Unimplemented: Read as 0

bit 6-4

LCxD2S<2:0>: Input Data 2 Selection Control bits(1)

111 = CLCxIN[11] is selected for lcxd2
110 = CLCxIN[10] is selected for lcxd2
101 = CLCxIN[9] is selected for lcxd2
100 = CLCxIN[8] is selected for lcxd2
011 = CLCxIN[7] is selected for lcxd2
010 = CLCxIN[6] is selected for lcxd2
001 = CLCxIN[5] is selected for lcxd2
000 = CLCxIN[4] is selected for lcxd2

bit 3

Unimplemented: Read as 0

bit 2-0

LCxD1S<2:0>: Input Data 1 Selection Control bits(1)

111 = CLCxIN[7] is selected for lcxd1
110 = CLCxIN[6] is selected for lcxd1
101 = CLCxIN[5] is selected for lcxd1
100 = CLCxIN[4] is selected for lcxd1
011 = CLCxIN[3] is selected for lcxd1
010 = CLCxIN[2] is selected for lcxd1
001 = CLCxIN[1] is selected for lcxd1
000 = CLCxIN[0] is selected for lcxd1

Note 1:

See Table 24-1 for signal names associated with inputs.

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Preliminary

DS41609A-page 279

PIC16(L)F1508/9
REGISTER 24-4:
U-0

CLCxSEL1: MULTIPLEXER DATA 3 AND 4 SELECT REGISTER

R/W-x/u

LCxD4S<2:0>

U-0

R/W-x/u

LCxD3S<2:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

Unimplemented: Read as 0

bit 6-4

LCxD4S<2:0>: Input Data 4 Selection Control bits(1)

111 = CLCxIN[3] is selected for lcxd4
110 = CLCxIN[2] is selected for lcxd4
101 = CLCxIN[1] is selected for lcxd4
100 = CLCxIN[0] is selected for lcxd4
011 = CLCxIN[15] is selected for lcxd4
010 = CLCxIN[14] is selected for lcxd4
001 = CLCxIN[13] is selected for lcxd4
000 = CLCxIN[12] is selected for lcxd4

bit 3

Unimplemented: Read as 0

bit 2-0

LCxD3S<2:0>: Input Data 3 Selection Control bits(1)

111 = CLCxIN[15] is selected for lcxd3
110 = CLCxIN[14] is selected for lcxd3
101 = CLCxIN[13] is selected for lcxd3
100 = CLCxIN[12] is selected for lcxd3
011 = CLCxIN[11] is selected for lcxd3
010 = CLCxIN[10] is selected for lcxd3
001 = CLCxIN[9] is selected for lcxd3
000 = CLCxIN[8] is selected for lcxd3

Note 1:

See Table 24-1 for signal names associated with inputs.

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PIC16(L)F1508/9
REGISTER 24-5:

CLCxGLS0: GATE 1 LOGIC SELECT REGISTER

R/W-x/u

LCxG1D4T

LCxG1D4N

LCxG1D3T

LCxG1D3N

LCxG1D2T

LCxG1D2N

LCxG1D1T

LCxG1D1N

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

LCxG1D4T: Gate 1 Data 4 True (non-inverted) bit

1 = lcxd4T is gated into lcxg1
0 = lcxd4T is not gated into lcxg1

bit 6

LCxG1D4N: Gate 1 Data 4 Negated (inverted) bit

1 = lcxd4N is gated into lcxg1
0 = lcxd4N is not gated into lcxg1

bit 5

LCxG1D3T: Gate 1 Data 3 True (non-inverted) bit

1 = lcxd3T is gated into lcxg1
0 = lcxd3T is not gated into lcxg1

bit 4

LCxG1D3N: Gate 1 Data 3 Negated (inverted) bit

1 = lcxd3N is gated into lcxg1
0 = lcxd3N is not gated into lcxg1

bit 3

LCxG1D2T: Gate 1 Data 2 True (non-inverted) bit

1 = lcxd2T is gated into lcxg1
0 = lcxd2T is not gated into lcxg1

bit 2

LCxG1D2N: Gate 1 Data 2 Negated (inverted) bit

1 = lcxd2N is gated into lcxg1
0 = lcxd2N is not gated into lcxg1

bit 1

LCxG1D1T: Gate 1 Data 1 True (non-inverted) bit

1 = lcxd1T is gated into lcxg1
0 = lcxd1T is not gated into lcxg1

bit 0

LCxG1D1N: Gate 1 Data 1 Negated (inverted) bit

1 = lcxd1N is gated into lcxg1
0 = lcxd1N is not gated into lcxg1

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Preliminary

DS41609A-page 281

PIC16(L)F1508/9
REGISTER 24-6:

CLCxGLS1: GATE 2 LOGIC SELECT REGISTER

R/W-x/u

LCxG2D4T

LCxG2D4N

LCxG2D3T

LCxG2D3N

LCxG2D2T

LCxG2D2N

LCxG2D1T

LCxG2D1N

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

LCxG2D4T: Gate 2 Data 4 True (non-inverted) bit

1 = lcxd4T is gated into lcxg2
0 = lcxd4T is not gated into lcxg2

bit 6

LCxG2D4N: Gate 2 Data 4 Negated (inverted) bit

1 = lcxd4N is gated into lcxg2
0 = lcxd4N is not gated into lcxg2

bit 5

LCxG2D3T: Gate 2 Data 3 True (non-inverted) bit

1 = lcxd3T is gated into lcxg2
0 = lcxd3T is not gated into lcxg2

bit 4

LCxG2D3N: Gate 2 Data 3 Negated (inverted) bit

1 = lcxd3N is gated into lcxg2
0 = lcxd3N is not gated into lcxg2

bit 3

LCxG2D2T: Gate 2 Data 2 True (non-inverted) bit

1 = lcxd2T is gated into lcxg2
0 = lcxd2T is not gated into lcxg2

bit 2

LCxG2D2N: Gate 2 Data 2 Negated (inverted) bit

1 = lcxd2N is gated into lcxg2
0 = lcxd2N is not gated into lcxg2

bit 1

LCxG2D1T: Gate 2 Data 1 True (non-inverted) bit

1 = lcxd1T is gated into lcxg2
0 = lcxd1T is not gated into lcxg2

bit 0

LCxG2D1N: Gate 2 Data 1 Negated (inverted) bit

1 = lcxd1N is gated into lcxg2
0 = lcxd1N is not gated into lcxg2

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PIC16(L)F1508/9
REGISTER 24-7:

CLCxGLS2: GATE 3 LOGIC SELECT REGISTER

R/W-x/u

LCxG3D4T

LCxG3D4N

LCxG3D3T

LCxG3D3N

LCxG3D2T

LCxG3D2N

LCxG3D1T

LCxG3D1N

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

LCxG3D4T: Gate 3 Data 4 True (non-inverted) bit

1 = lcxd4T is gated into lcxg3
0 = lcxd4T is not gated into lcxg3

bit 6

LCxG3D4N: Gate 3 Data 4 Negated (inverted) bit

1 = lcxd4N is gated into lcxg3
0 = lcxd4N is not gated into lcxg3

bit 5

LCxG3D3T: Gate 3 Data 3 True (non-inverted) bit

1 = lcxd3T is gated into lcxg3
0 = lcxd3T is not gated into lcxg3

bit 4

LCxG3D3N: Gate 3 Data 3 Negated (inverted) bit

1 = lcxd3N is gated into lcxg3
0 = lcxd3N is not gated into lcxg3

bit 3

LCxG3D2T: Gate 3 Data 2 True (non-inverted) bit

1 = lcxd2T is gated into lcxg3
0 = lcxd2T is not gated into lcxg3

bit 2

LCxG3D2N: Gate 3 Data 2 Negated (inverted) bit

1 = lcxd2N is gated into lcxg3
0 = lcxd2N is not gated into lcxg3

bit 1

LCxG3D1T: Gate 3 Data 1 True (non-inverted) bit

1 = lcxd1T is gated into lcxg3
0 = lcxd1T is not gated into lcxg3

bit 0

LCxG3D1N: Gate 3 Data 1 Negated (inverted) bit

1 = lcxd1N is gated into lcxg3
0 = lcxd1N is not gated into lcxg3

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Preliminary

DS41609A-page 283

PIC16(L)F1508/9
REGISTER 24-8:

CLCxGLS3: GATE 4 LOGIC SELECT REGISTER

R/W-x/u

LCxG4D4T

LCxG4D4N

LCxG4D3T

LCxG4D3N

LCxG4D2T

LCxG4D2N

LCxG4D1T

LCxG4D1N

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

LCxG4D4T: Gate 4 Data 4 True (non-inverted) bit

1 = lcxd4T is gated into lcxg4
0 = lcxd4T is not gated into lcxg4

bit 6

LCxG4D4N: Gate 4 Data 4 Negated (inverted) bit

1 = lcxd4N is gated into lcxg4
0 = lcxd4N is not gated into lcxg4

bit 5

LCxG4D3T: Gate 4 Data 3 True (non-inverted) bit

1 = lcxd3T is gated into lcxg4
0 = lcxd3T is not gated into lcxg4

bit 4

LCxG4D3N: Gate 4 Data 3 Negated (inverted) bit

1 = lcxd3N is gated into lcxg4
0 = lcxd3N is not gated into lcxg4

bit 3

LCxG4D2T: Gate 4 Data 2 True (non-inverted) bit

1 = lcxd2T is gated into lcxg4
0 = lcxd2T is not gated into lcxg4

bit 2

LCxG4D2N: Gate 4 Data 2 Negated (inverted) bit

1 = lcxd2N is gated into lcxg4
0 = lcxd2N is not gated into lcxg4

bit 1

LCxG4D1T: Gate 4 Data 1 True (non-inverted) bit

1 = lcxd1T is gated into lcxg4
0 = lcxd1T is not gated into lcxg4

bit 0

LCxG4D1N: Gate 4 Data 1 Negated (inverted) bit

1 = lcxd1N is gated into lcxg4
0 = lcxd1N is not gated into lcxg4

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PIC16(L)F1508/9
REGISTER 24-9:

CLCDATA: CLC DATA OUTPUT

U-0

R-0

MLC4OUT

MLC3OUT

MLC2OUT

MLC1OUT

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

Unimplemented: Read as 0

bit 3

MLC4OUT: Mirror copy of LC4OUT bit

bit 2

MLC3OUT: Mirror copy of LC3OUT bit

bit 1

MLC2OUT: Mirror copy of LC2OUT bit

bit 0

MLC1OUT: Mirror copy of LC1OUT bit

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DS41609A-page 285

PIC16(L)F1508/9
TABLE 24-3:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH CLCx

Bit4

BIt3

Bit2

ANSC3

ANSC2

SSSEL

T1GSEL

Bit0

ANSC1

ANSC0

123

CLC1SEL

NCO1SEL

112

Bit7

Bit6

Bit5

Bit1

ANSELC

ANSC7

ANSC6

APFCON

CLC1CON

LC1EN

LC1OE

LC1OUT

LC1INTP

LC1INTN

LC1MODE<2:0>

277

CLC2CON

LC2EN

LC2OE

LC2OUT

LC2INTP

LC2INTN

LC2MODE<2:0>

277

CLCDATA

MLC4OUT

MLC3OUT

MLC2OUT

MLC1OUT

281

CLC1GLS0

LC1G1D4T

LC1G1D4N

LC1G1D3T

LC1G1D3N

LC1G1D2T

LC1G1D2N

LC1G1D1T

LC1G1D1N

281

CLC1GLS1

LC1G2D4T

LC1G2D4N

LC1G2D3T

LC1G2D3N

LC1G2D2T

LC1G2D2N

LC1G2D1T

LC1G2D1N

282

CLC1GLS2

LC1G3D4T

LC1G3D4N

LC1G3D3T

LC1G3D3N

LC1G3D2T

LC1G3D2N

LC1G3D1T

LC1G3D1N

283

CLC1GLS3

LC1G4D4T

LC1G4D4N

LC1G4D3T

LC1G4D3N

LC1G4D2T

LC1G4D2N

LC1G4D1T

LC1G4D1N

284

CLC1POL

LC1POL

LC1G4POL

LC1G3POL

LC1G2POL

LC1G1POL

278

CLC1SEL0

LC1D2S<2:0>

LC1D1S<2:0>

279

CLC1SEL1

LC1D4S<2:0>

LC1D3S<2:0>

280

CLC2GLS0

LC2G1D4T

LC2G1D4N

LC2G1D3T

LC2G1D3N

LC2G1D2T

LC2G1D2N

LC2G1D1T

LC2G1D1N

281

CLC2GLS1

LC2G2D4T

LC2G2D4N

LC2G2D3T

LC2G2D3N

LC2G2D2T

LC2G2D2N

LC2G2D1T

LC2G2D1N

282

CLC2GLS2

LC2G3D4T

LC2G3D4N

LC2G3D3T

LC2G3D3N

LC2G3D2T

LC2G3D2N

LC2G3D1T

LC2G3D1N

283

CLC2GLS3

LC2G4D4T

LC2G4D4N

LC2G4D3T

LC2G4D3N

LC2G4D2T

LC2G4D2N

LC2G4D1T

LC2G4D1N

284

CLC2POL

LC2POL

LC2G4POL

LC2G3POL

LC2G2POL

LC2G1POL

278

CLC2SEL0

LC2D2S<2:0>

LC2D4S<2:0>

LC2D1S<2:0>

279

CLC2SEL1

CLC3GLS0

LC3G1D4T

LC3G1D4N

LC3G1D3T

LC3G1D3N

LC3G1D2T

LC3G1D2N

LC2D3S<2:0>
LC3G1D1T

LC3G1D1N

280
281

CLC3GLS1

LC3G2D4T

LC3G2D4N

LC3G2D3T

LC3G2D3N

LC3G2D2T

LC3G2D2N

LC3G2D1T

LC3G2D1N

282

CLC3GLS2

LC3G3D4T

LC3G3D4N

LC3G3D3T

LC3G3D3N

LC3G3D2T

LC3G3D2N

LC3G3D1T

LC3G3D1N

283

CLC3GLS3

LC3G4D4T

LC3G4D4N

LC3G4D3T

LC3G4D3N

LC3G4D2T

LC3G4D2N

LC3G4D1T

LC3G4D1N

284

LC3G4POL

LC3G3POL

LC3G2POL

LC3G1POL

278

CLC3POL

LC3POL

CLC3SEL0

LC3D2S<2:0>

LC3D1S<2:0>

279

CLC3SEL1

LC3D4S<2:0>

LC3D3S<2:0>

280

CLC4GLS0

LC4G1D4T

LC4G1D4N

LC4G1D3T

LC4G1D3N

LC4G1D2T

LC4G1D2N

LC4G1D1T

LC4G1D1N

281

CLC4GLS1

LC4G2D4T

LC4G2D4N

LC4G2D3T

LC4G2D3N

LC4G2D2T

LC4G2D2N

LC4G2D1T

LC4G2D1N

282

CLC4GLS2

LC4G3D4T

LC4G3D4N

LC4G3D3T

LC4G3D3N

LC4G3D2T

LC4G3D2N

LC4G3D1T

LC4G3D1N

283

CLC4GLS3

LC4G4D4T

LC4G4D4N

LC4G4D3T

LC4G4D3N

LC4G4D2T

LC4G4D2N

LC4G4D1T

LC4G4D1N

284

CLC4POL

LC4POL

LC4G4POL

LC4G3POL

LC4G2POL

LC4G1POL

278

CLC4SEL0

LC4D2S<2:0>

LC4D1S<2:0>

CLC4SEL1

LC4D4S<2:0>

LC4D3S<2:0>

279
280

GIE

PEIE

TMR0IE

INTE

IOCIE

TMR0IF

INTF

IOCIF

PIE3

CLC4IE

CLC3IE

CLC2IE

CLC1IE

PIR3

CLC4IF

CLC3IF

CLC2IF

CLC1IF

TRISA2

TRISA1

TRISA0

114

TRISC2

TRISC1

TRISC0

122

INTCON

TRISA

TRISA5

TRISA4

(1)

TRISC

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

Legend:
Note 1:

= unimplemented read as 0,. Shaded cells are not used for CLC module.
Unimplemented, read as 1.

DS41609A-page 286

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
25.0

NUMERICALLY CONTROLLED
OSCILLATOR (NCO) MODULE

The Numerically Controlled Oscillator (NCOx) module

is a timer that uses the overflow from the addition of an
increment value to divide the input frequency. The
advantage of the addition method over simple counter
driven timer is that the resolution of division does not
vary with the divider value. The NCOx is most useful for
applications that require frequency accuracy and fine
resolution at a fixed duty cycle.
Features of the NCOx include:

16-bit increment function

Fixed Duty Cycle (FDC) mode
Pulse Frequency (PF) mode
Output pulse width control
Multiple clock input sources
Output polarity control
Interrupt capability

Figure 25-1 is a simplified block diagram of the NCOx

module.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 287

NUMERICALLY CONTROLLED OSCILLATOR (NCOx) MODULE SIMPLIFIED BLOCK DIAGRAM

Increment
16

(1)
Buffer
16

Interrupt event

Set NCOxIF flag

NCO1CLK

LC1OUT
FOSC

Preliminary

HFINTOSC

Accumulator

NCOxOUT

NxOE

Overflow
Q

NCOx Clock

TRIS Control

NxEN

NCOx

NxCKS<2:0>

Overflow

NxPFM
NxPOL

3
2011 Microchip Technology Inc.

NCOx Clock

Ripple Counter

Note 1:

To CLC, CWG

NxPWS<2:0>

Reset

The increment registers are double-buffered to allow for value changes to be made without first disabling the NCOx
module. They are shown here for reference. The buffers are not user-accessible.

PIC16(L)F1508/9

DS41609A-page 288

FIGURE 25-1:

PIC16(L)F1508/9
25.1

NCOx OPERATION

25.1.3

ADDER

The NCOx operates by repeatedly adding a fixed value

to an accumulator. Additions occur at the input clock
rate. The accumulator will overflow with a carry
periodically, which is the raw NCOx output. This
effectively reduces the input clock by the ratio of the
addition value to the maximum accumulator value. See
Equation 25-1.

The NCOx Adder is a full adder, which operates

independently from the system clock. The addition of
the previous result and the increment value replaces
the accumulator value on the rising edge of each input
clock.

The NCOx output can be further modified by stretching

the pulse or toggling a flip-flop. The modified NCOx
output is then distributed internally to other peripherals
and optionally output to a pin. The accumulator overflow
also generates an interrupt.

The Increment value is stored in two 8-bit registers

making up a 16-bit increment. In order of LSB to MSB
they are:

The NCOx period changes in discrete steps to create an

average frequency. This output depends on the ability of
the receiving circuit (i.e., CWG or external resonant
converter circuitry) to average the NCOx output to
reduce uncertainty.

Both of the registers are readable and writeable. The

Increment registers are double-buffered to allow for
value changes to be made without first disabling the
NCOx module.

25.1.1

NCOx CLOCK SOURCES

Clock sources available to the NCOx include:

HFINTOSC
FOSC
LC1OUT
CLKIN pin

25.1.4

INCREMENT REGISTERS

NCOxINCL
NCOxINCH

The buffer loads are immediate when the module is disabled. Writing to the NCOxINCH register first is necessary because then the buffer is loaded synchronously
with the NCOx operation after the write is executed on
the NCOxINCL register.
Note: The increment buffer registers are not
user-accessible.

The NCOx clock source is selected by configuring the

NxCKS<2:0> bits in the NCOxCLK register.

25.1.2

ACCUMULATOR

The accumulator is a 20-bit register. Read and write

access to the accumulator is available through three
registers:
NCOxACCL
NCOxACCH
NCOxACCU

EQUATION 25-1:

NCO Clock Frequency Increment Value

F OVERFLOW = --------------------------------------------------------------------------------------------------------------n
2
n = Accumulator width in bits

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 289

PIC16(L)F1508/9
25.2

FIXED DUTY CYCLE (FDC) MODE

In Fixed Duty Cycle (FDC) mode, every time the

accumulator overflows, the output is toggled. This
provides a 50% duty cycle, provided that the increment
value remains constant. For more information, see
Figure 25-2.
The FDC mode is selected by clearing the NxPFM bit
in the NCOxCON register.

25.3

PULSE FREQUENCY (PF) MODE

In Pulse Frequency (PF) mode, every time the accumulator overflows, the output becomes active for one or
more clock periods. Once the clock period expires, the
output returns to an inactive state. This provides a
pulsed output.
The output becomes active on the rising clock edge
immediately following the overflow event. For more
information, see Figure 25-2.
The value of the active and inactive states depends on
the polarity bit, NxPOL in the NCOxCON register.
The PF mode is selected by setting the NxPFM bit in
the NCOxCON register.

25.3.1

OUTPUT PULSE WIDTH CONTROL

When operating in PF mode, the active state of the output can vary in width by multiple clock periods. Various
pulse widths are selected with the NxPWS<2:0> bits in
the NCOxCLK register.
When the selected pulse width is greater than the
accumulator overflow time frame, the output of the
NCOx operation is indeterminate.

25.4

OUTPUT POLARITY CONTROL

The last stage in the NCOx module is the output polarity. The NxPOL bit in the NCOxCON register selects the
output polarity. Changing the polarity while the interrupts are enabled will cause an interrupt for the resulting output transition.
The NCOx output can be used internally by source
code or other peripherals. Accomplish this by reading
the NxOUT (read-only) bit of the NCOxCON register.

DS41609A-page 290

Preliminary

2011 Microchip Technology Inc.

FDC OUTPUT MODE OPERATION DIAGRAM

Clock Source

NCOx
Increment
Value

NCOx
Accumulator
Input

2000h

02000h

04000h

06000h

08000h

0A000h

0C000h

0E000h

10000h

02000h

04000h

06000h

08000h

0A000h

0C000h

0E000h

10000h

02000h

2000h

4000h

6000h

8000h

A000h

C000h

E000h

0000h

04000h

Tadder
Overflow is the
MSB of the accumulator

Accumulator Input Overflow

Preliminary

Tadder_
NCOx
Accumulator
Value

0000h

2000h

4000h

6000h

8000h

A000h

C000h

E000h

0000h

Tadder
Overflow
PWS = 000

Interrupt
Event

2011 Microchip Technology Inc.

NCOx Output
FDC mode

NCOx Output PF mode

NCOX PWS = 000

NCOx Output PF mode

NCOx PWS = 010

Tadder

2000h

PIC16(L)F1508/9

DS41609A-page 291

FIGURE 25-2:

PIC16(L)F1508/9
25.5

Interrupts

When the accumulator overflows, the NCOx Interrupt

Flag bit, NCOxIF, of the PIRx register is set. To enable
the interrupt event, the following bits must be set:

NxEN bit of the NCOxCON register

NCOxIE bit of the PIEx register
PEIE bit of the INTCON register
GIE bit of the INTCON register

The interrupt must be cleared by software by clearing

the NCOxIF bit in the Interrupt Service Routine.

25.6

Effects of a Reset

All of the NCOx registers are cleared to zero as the

result of a Reset.

25.7

Operation In Sleep

The NCO module operates independently from the

system clock and will continue to run during Sleep,
provided that the clock source selected remains
active.
The HFINTOSC remains active during Sleep when the
NCO module is enabled and the HFINTOSC is
selected as the clock source, regardless of the system
clock source selected.
In other words, if the HFINTOSC is simultaneously
selected as the system clock and the NCO clock
source, when the NCO is enabled, the CPU will go idle
during Sleep, but the NCO will continue to operate and
the HFINTOSC will remain active.
This will have a direct effect on the Sleep mode current.

25.8

Alternate Pin Locations

This module incorporates I/O pins that can be moved to

DS41609A-page 292

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
25.9

NCOx Control Registers

NCOxCON: NCOx CONTROL REGISTER

R/W-0/0

R-0/0

R/W-0/0

U-0

R/W-0/0

NxEN

NxOE

NxOUT

NxPOL

NxPFM

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7

NxEN: NCOx Enable bit

1 = NCOx module is enabled
0 = NCOx module is disabled

bit 6

NxOE: NCOx Output Enable bit

1 = NCOx output pin is enabled
0 = NCOx output pin is disabled

bit 5

NxOUT: NCOx Output bit

1 = NCOx output is high
0 = NCOx output is low

bit 4

NxPOL: NCOx Polarity bit

1 = NCOx output signal is active-high
0 = NCOx output signal is active-low

bit 3-1

Unimplemented: Read as 0.

bit 0

NxPFM: NCOx Pulse Frequency Mode bit

1 = NCOx operates in Pulse Frequency mode
0 = NCOx operates in Fixed Duty Cycle mode

NCOxCLK: NCOx INPUT CLOCK CONTROL REGISTER

R/W-0/0

NxPWS<2:0>

U-0

R/W-0/0

NxCKS<1:0>

bit 7

bit 0

Legend:
R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-5

NxPWS<2:0>: NCOx Output Pulse Width Select bits(1, 2)

111 = 128 NCOx clock periods
110 = 64 NCOx clock periods
101 = 32 NCOx clock periods
100 = 16 NCOx clock periods
011 = 8 NCOx clock periods
010 = 4 NCOx clock periods
001 = 2 NCOx clock periods
000 = 1 NCOx clock periods

bit 4-2

Unimplemented: Read as 0

bit 1-0

NxCKS<1:0>: NCOx Clock Source Select bits

11 = NCO1CLK
10 = LC1OUT
01 = FOSC
00 = HFINTOSC (16 MHz)

Note 1: NxPWS applies only when operating in Pulse Frequency mode.

2: If NCOx pulse width is greater than NCOx overflow period, operation is undeterminate.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 293

PIC16(L)F1508/9
REGISTER 25-3:
R/W-0/0

NCOxACCL: NCOx ACCUMULATOR REGISTER LOW BYTE

R/W-0/0

NCOxACC<7:0>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

NCOxACC<7:0>: NCOx Accumulator, low byte

NCOxACCH: NCOx ACCUMULATOR REGISTER HIGH BYTE

R/W-0/0

NCOxACC<15:8>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

NCOxACC<15:8>: NCOx Accumulator, high byte

NCOxACCU: NCOx ACCUMULATOR REGISTER UPPER BYTE

U-0

R/W-0/0

NCOxACC<19:16>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-4

Unimplemented: Read as 0

bit 3-0

NCOxACC<19:16>: NCOx Accumulator, upper byte

DS41609A-page 294

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 25-6:
R/W-0/0

NCOxINCL: NCOx INCREMENT REGISTER LOW BYTE

R/W-0/0

R/W-1/1

NCOxINC<7:0>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

NCOxINC<7:0>: NCOx Increment, low byte

NCOxINCH: NCOx INCREMENT REGISTER HIGH BYTE

R/W-0/0

NCOxINC<15:8>
bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

bit 7-0

NCOxINC<15:8>: NCOx Increment, high byte

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 295

PIC16(L)F1508/9
TABLE 25-1:
Name

SUMMARY OF REGISTERS ASSOCIATED WITH NCOx

Bit 2

Bit 1

Bit 0

T1GSEL

CLC1SEL

NCO1SEL

112

IOCIE

TMR0IF

INTF

IOCIF

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

APFCON

SSSEL

INTCON

GIE

PEIE

TMR0IE

INTE

NCO1ACCH

NCO1ACC<15:8>

294

NCO1ACCL

NCO1ACC<7:0>

294

NCO1ACCU
NCO1CLK
NCO1CON

NCO1ACC<19:16>

N1PWS<2:0>
N1EN

N1OE

N1OUT

NCO1INCH

N1POL

294

N1CKS<1:0>

N1PFM

NCO1INC<15:8>

NCO1INCL

293
293
295

NCO1INC<7:0>

295

PIE2

OSFIE

C2IE

C1IE

BCL1IE

NCO1IE

PIR2

OSFIF

C2IF

C1IF

BCL1IF

NCO1IF

TRISA5

TRISA4

(1)

TRISA2

TRISA1

TRISA0

114

TRISC7

TRISC6

TRISC5

TRISC4

TRISC3

TRISC2

TRISC1

TRISC0

122

TRISA
TRISC

Legend:
Note 1:

x = unknown, u = unchanged, = unimplemented read as 0, q = value depends on condition. Shaded cells are not
used for NCOx module.
Unimplemented, read as 1.

DS41609A-page 296

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
26.0

COMPLEMENTARY WAVEFORM
GENERATOR (CWG) MODULE

The Complementary Waveform Generator (CWG) produces a complementary waveform with dead-band
delay from a selection of input sources.
The CWG module has the following features:

Selectable dead-band clock source control

Selectable input sources
Output enable control
Output polarity control
Dead-band control with independent 6-bit rising
and falling edge dead-band counters
Auto-shutdown control with:
- Selectable shutdown sources
- Auto-restart enable
- Auto-shutdown pin override control

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 297

2011 Microchip Technology Inc.

FIGURE 26-1:

SIMPLIFIED CWG BLOCK DIAGRAM

GxASDLA

GxCS

FOSC

cwg_clock

GxASDLA = 01
GxOEA

CWGxDBR

HFINTOSC

GxIS

Preliminary

async_C1OUT
async_C2OUT
PWM1OUT
PWM2OUT
PWM3OUT
PWM4OUT
NCO1OUT
LC1OUT

EN
R
S

TRISx

GxPOLA

Input Source

CWGxA

CWGxDBF
6
EN

GxOEB
R

TRISx

0
GxPOLB

CWGxB

GxASDLB = 01
CWG1FLT (INT pin)

GxASDFLT
async_C1OUT
GxASDC1
async_C2OUT
GxASDC2
LC2OUT
GxASCLC

DS41609A-page 298

GxASE Data Bit

WRITE
x = CWG module number

GxASE

Auto-Shutdown
Source

GxARSEN

set dominate

shutdown

GxASDLB

PIC16(L)F1508/9

PIC16(L)F1508/9
FIGURE 26-2:

TYPICAL CWG OPERATION WITH PWM1 (NO AUTO-SHUTDOWN)

cwg_clock
PWM1
CWGxA
Rising Edge
Dead Band

Falling Edge Dead Band

Rising Edge Dead Band

Rising Edge D
Falling Edge Dead Band

CWGxB

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 299

PIC16(L)F1508/9
26.1

Fundamental Operation

The CWG generates a two output complementary

waveform from one of four selectable input sources.
The off-to-on transition of each output can be delayed
from the on-to-off transition of the other output, thereby,
creating a time delay immediately where neither output
is driven. This is referred to as dead time and is covered
in Section 26.5 Dead-Band Control. A typical
operating waveform, with dead band, generated from a
single input signal is shown in Figure 26-2.
It may be necessary to guard against the possibility of
circuit faults or a feedback event arriving too late or not
at all. In this case, the active drive must be terminated
before the Fault condition causes damage. This is
referred to as auto-shutdown and is covered in
Section 26.9 Auto-shutdown Control.

26.2

Clock Source

The CWG module allows the following clock sources

to be selected:
Fosc (system clock)
HFINTOSC (16 MHz only)
The clock sources are selected using the G1CS0 bit of
the CWGxCON0 register (Register 26-1).

26.3

async_C1OUT
async_C2OUT
PWM1OUT
PWM2OUT
PWM3OUT
PWM4OUT
NCO1OUT
LC1OUT

Output Control

Immediately after the CWG module is enabled, the

complementary drive is configured with both CWGxA
and CWGxB drives cleared.

26.4.1

POLARITY CONTROL

The polarity of each CWG output can be selected

independently. When the output polarity bit is set, the
corresponding output is active high. Clearing the output
polarity bit configures the corresponding output as
active low. However, polarity does not affect the
override levels. Output polarity is selected with the
GxPOLA and GxPOLB bits of the CWGxCON0 register.

26.5

Dead-Band Control

Dead-band control provides for non-overlapping output

signals to prevent shoot-through current in power
switches. The CWG contains two 6-bit dead-band
counters. One dead-band counter is used for the rising
edge of the input source control. The other is used for
the falling edge of the input source control.
Dead band is timed by counting CWG clock periods
from zero up to the value in the rising or falling deadband counter registers. See CWGxDBR and
CWGxDBF registers (Register 26-4 and Register 26-5,
respectively).

Rising Edge Dead Band

The rising edge dead-band delays the turn-on of the

CWGxA output from when the CWGxB output is turned
off. The rising edge dead-band time starts when the
rising edge of the input source signal goes true. When
this happens, the CWGxB output is immediately turned
off and the rising edge dead-band delay time starts.
When the rising edge dead-band delay time is reached,
the CWGxA output is turned on.
The CWGxDBR register sets the duration of the deadband interval on the rising edge of the input source
signal. This duration is from 0 to 64 counts of dead band.

The input sources are selected using the GxIS<2:0>

bits in the CWGxCON1 register (Register 26-2).

26.4

26.4.2

26.6

Selectable Input Sources

The CWG can generate the complementary waveform

for the following input sources:

enables are dependent on the module enable bit,

GxEN. When GxEN is cleared, CWG output enables
and CWG drive levels have no effect.

Dead band is always counted off the edge on the input

source signal. A count of 0 (zero), indicates that no
dead band is present.
If the input source signal is not present for enough time
for the count to be completed, no output will be seen on
the respective output.

OUTPUT ENABLES

Each CWG output pin has individual output enable

control. Output enables are selected with the GxOEA
and GxOEB bits of the CWGxCON0 register. When an
output enable control is cleared, the module asserts no
control over the pin. When an output enable is set, the
override value or active PWM waveform is applied to
the pin per the port priority selection. The output pin

DS41609A-page 300

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
26.7

Falling Edge Dead Band

The falling edge dead band delays the turn-on of the

CWGxB output from when the CWGxA output is turned
off. The falling edge dead-band time starts when the
falling edge of the input source goes true. When this
happens, the CWGxA output is immediately turned off
and the falling edge dead-band delay time starts. When
the falling edge dead-band delay time is reached, the
CWGxB output is turned on.
The CWGxDBF register sets the duration of the deadband interval on the falling edge of the input source signal. This duration is from 0 to 64 counts of dead band.
Dead band is always counted off the edge on the input
source signal. A count of 0 (zero), indicates that no
dead band is present.
If the input source signal is not present for enough time
for the count to be completed, no output will be seen on
the respective output.
Refer to Figure 26-3 and Figure 26-4 for examples.

26.8

Dead-Band Uncertainty

When the rising and falling edges of the input source

triggers the dead-band counters, the input may be asynchronous. This will create some uncertainty in the deadband time delay. The maximum uncertainty is equal to
one CWG clock period. Refer to Equation 26-1 for more
detail.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 301

2011 Microchip Technology Inc.

FIGURE 26-3:

DEAD-BAND OPERATION, CWGxDBR = 01H, CWGxDBF = 02H

cwg_clock
Input Source
CWGxA
CWGxB

FIGURE 26-4:

DEAD-BAND OPERATION, CWGxDBR = 03H, CWGxDBF = 04H, SOURCE SHORTER THAN DEAD BAND

Preliminary

cwg_clock
Input Source
CWGxA

DS41609A-page 302

PIC16(L)F1508/9

source shorter than dead band

CWGxB

PIC16(L)F1508/9
EQUATION 26-1:

DEAD-BAND
UNCERTAINTY

1
TDEADBAND_UNCERTAINTY = ----------------------------Fcwg_clock

Example:

Fcwg_clock = 16 MHz

Therefore:

1
TDEADBAND_UNCERTAINTY = ----------------------------Fcwg_clock
1
= ------------------16 MHz
= 62.5ns

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 303

PIC16(L)F1508/9
26.9

Auto-shutdown Control

26.10 Operation During Sleep

Auto-shutdown is a method to immediately override the

CWG output levels with specific overrides that allow for
safe shutdown of the circuit. The shutdown state can be
either cleared automatically or held until cleared by
software.

26.9.1

SHUTDOWN

The shutdown state can be entered by either of the following two methods:
Software generated
External Input

26.9.1.1

Software Generated Shutdown

Setting the GxASE bit of the CWGxCON2 register will

force the CWG into the shutdown state.
When auto-restart is disabled, the shutdown state will
persist as long as the GxASE bit is set.

The CWG module operates independently from the

system clock and will continue to run during Sleep,
provided that the clock and input sources selected
remain active.
The HFINTOSC remains active during Sleep, provided
that the CWG module is enabled, the input source is
active, and the HFINTOSC is selected as the clock
source, regardless of the system clock source
selected.
In other words, if the HFINTOSC is simultaneously
selected as the system clock and the CWG clock
source, when the CWG is enabled and the input
source is active, the CPU will go idle during Sleep, but
the CWG will continue to operate and the HFINTOSC
will remain active.
This will have a direct effect on the Sleep mode current.

When auto-restart is enabled, the GxASE bit will clear

automatically and resume operation on the next rising
edge event. See Figure 26-6.

26.9.1.2

External Input Source

External shutdown inputs provide the fastest way to

safely suspend CWG operation in the event of a Fault
condition. When any of the selected shutdown inputs
goes active, the CWG outputs will immediately go to
the selected override levels without software delay. Any
combination of two input sources can be selected to
cause a shutdown condition. The sources are:

async_C1OUT
async_C2OUT
LC2OUT
CWG1FLT

Shutdown inputs are selected using the GxASDS0 and

GxASDS1 bits of the CWGxCON2 register.
(Register 26-3).
Note:

Shutdown inputs are level sensitive, not

edge sensitive. The shutdown state cannot be cleared, except by disabling autoshutdown, as long as the shutdown input
level persists.

DS41609A-page 304

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
26.11 Configuring the CWG

26.11.1

The following steps illustrate how to properly configure

the CWG to ensure a synchronous start:

The levels driven to the output pins, while the shutdown

input is true, are controlled by the GxASDLA and
GxASDLB bits of the CWGxCON2 register
(Register 26-3). GxASDLA controls the CWG1A
override level and GxASDLB controls the CWG1B
override level. The control bit logic level corresponds to
the output logic drive level while in the shutdown state.
The polarity control does not apply to the override level.

2.
3.
4.

5.
6.

7.
8.

Ensure that the TRIS control bits corresponding

to CWGxA and CWGxB are set so that both are
configured as inputs.
Clear the GxEN bit, if not already cleared.
Set desired dead-band times with the CWGxDBR
and CWGxDBF registers.
Setup the following controls in CWGxCON2
auto-shutdown register:
Select desired shutdown source.
Select both output overrides to the desired
levels (this is necessary even if not using
auto-shutdown because start-up will be from
a shutdown state).
Set the GxASE bit and clear the GxARSEN
bit.
Select the desired input source using the
CWGxCON1 register.
Configure the following controls in CWGxCON0
register:
Select desired clock source.
Select the desired output polarities.
Set the output enables for the outputs to be
used.
Set the GxEN bit.
Clear TRIS control bits corresponding to
CWGxA and CWGxB to be used to configure
those pins as outputs.
If auto-restart is to be used, set the GxARSEN
bit and the GxASE bit will be cleared automatically. Otherwise, clear the GxASE bit to start the
CWG.

2011 Microchip Technology Inc.

26.11.2

PIN OVERRIDE LEVELS

AUTO-SHUTDOWN RESTART

After an auto-shutdown event has occurred, there are

two ways to have resume operation:
Software controlled
Auto-restart
The restart method is selected with the GxARSEN bit
of the CWGxCON2 register. Waveforms of software
controlled and automatic restarts are shown in
Figure 26-5 and Figure 26-6.

26.11.2.1

Software controlled restart

When the GxARSEN bit of the CWGxCON2 register is

cleared, the CWG must be restarted after an auto-shutdown event by software.
Clearing the shutdown state requires all selected shutdown inputs to be low, otherwise the GxASE bit will
remain set. The overrides will remain in effect until the
first rising edge event after the GxASE bit is cleared.
The CWG will then resume operation.

26.11.2.2

Auto-Restart

When the GxARSEN bit of the CWGxCON2 register is

set, the CWG will restart from the auto-shutdown state
automatically.
The GxASE bit will clear automatically when all shutdown sources go low. The overrides will remain in
effect until the first rising edge event after the GxASE
bit is cleared. The CWG will then resume operation.

Preliminary

DS41609A-page 305

2011 Microchip Technology Inc.

FIGURE 26-5:

SHUTDOWN FUNCTIONALITY, AUTO-RESTART DISABLED (GxARSEN = 0,GxASDLA = 01, GxASDLB = 01)

Shutdown Event Ceases

GxASE Cleared by Software

CWG Input
Source
Shutdown Source
GxASE

CWG1A

Tri-State (No Pulse)

CWG1B

Tri-State (No Pulse)

No Shutdown

Preliminary

Output Resumes

Shutdown

FIGURE 26-6:

SHUTDOWN FUNCTIONALITY, AUTO-RESTART ENABLED (GxARSEN = 1,GxASDLA = 01, GxASDLB = 01)

Shutdown Event Ceases

GxASE auto-cleared by hardware

Shutdown Source

GxASE

DS41609A-page 306

CWG1A

Tri-State (No Pulse)

CWG1B

Tri-State (No Pulse)

No Shutdown
Shutdown

Output Resumes

PIC16(L)F1508/9

CWG Input
Source

PIC16(L)F1508/9
26.12

CWG Control Registers

CWGxCON0: CWG CONTROL REGISTER 0

R/W-0/0

U-0

R/W-0/0

GxEN

GxOEB

GxOEA

GxPOLB

GxPOLA

GxCS0

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7

GxEN: CWGx Enable bit

1 = Module is enabled
0 = Module is disabled

bit 6

GxOEB: CWGxB Output Enable bit

1 = CWGxB is available on appropriate I/O pin
0 = CWGxB is not available on appropriate I/O pin

bit 5

GxOEA: CWGxA Output Enable bit

1 = CWGxA is available on appropriate I/O pin
0 = CWGxA is not available on appropriate I/O pin

bit 4

GxPOLB: CWGxB Output Polarity bit

1 = Output is inverted polarity
0 = Output is normal polarity

bit 3

GxPOLA: CWGxA Output Polarity bit

1 = Output is inverted polarity
0 = Output is normal polarity

bit 2-1

Unimplemented: Read as 0

bit 0

GxCS0: CWGx Clock Source Select bit

1 = HFINTOSC
0 = FOSC

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 307

PIC16(L)F1508/9
REGISTER 26-2:
R/W-x/u

CWGxCON1: CWG CONTROL REGISTER 1

R/W-x/u

GxASDLB<1:0>

R/W-x/u

U-0

GxASDLA<1:0>

R/W-0/0

GxIS<2:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7-6

GxASDLB<1:0>: CWGx Shutdown State for CWGxB

When an auto shutdown event is present (GxASE = 1):
11 = CWGxB pin is driven to 1, regardless of the setting of the GxPOLB bit.
10 = CWGxB pin is driven to 0, regardless of the setting of the GxPOLB bit.
01 = CWGxB pin is tri-stated
00 = CWGxB pin is driven to its inactive state after the selected dead-band interval. GxPOLB still will
control the polarity of the output.

bit 5-4

GxASDLA<1:0>: CWGx Shutdown State for CWGxA

When an auto shutdown event is present (GxASE = 1):
11 = CWGxA pin is driven to 1, regardless of the setting of the GxPOLA bit.
10 = CWGxA pin is driven to 0, regardless of the setting of the GxPOLA bit.
01 = CWGxA pin is tri-stated
00 = CWGxA pin is driven to its inactive state after the selected dead-band interval. GxPOLA still will
control the polarity of the output.

bit 3

Unimplemented: Read as 0

bit 2-0

GxIS<2:0>: CWGx Input Source Select bits

111 = LC1OUT
110 = NCO1OUT
101 = PWM4OUT
100 = PWM3OUT
011 = PWM2OUT
010 = PWM1OUT
001 = async_C1OUT
000 = async_C2OUT

DS41609A-page 308

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
REGISTER 26-3:

CWGxCON2: CWG CONTROL REGISTER 2

R/W-0/0

GxASE

GxARSEN

U-0

R/W-0/0

GxASDC2

GxASDC1

GxASDFLT

GxASDCLC2

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7

GxASE: Auto-Shutdown Event Status bit

1 = An auto-shutdown event has occurred
0 = No auto-shutdown event has occurred

bit 6

GxARSEN: Auto-Restart Enable bit

1 = Auto-restart is enabled
0 = Auto-restart is disabled

bit 5-4

Unimplemented: Read as 0

bit 3

GxASDC2: CWG Auto-shutdown on Comparator 2 Enable

1 = Shutdown when Comparator 2 output is high
0 = Comparator 2 output has no effect on shutdown

bit 2

GxASDC1: CWG Auto-shutdown on Comparator 1 Enable

1 = Shutdown when Comparator 1 output is high
0 = Comparator 1 output has no effect on shutdown

bit 1

GxASDFLT: CWG Auto-shutdown on FLT Enable bit

1 = Shutdown when CWG1FLT input is low
0 = CWG1FLT input has no effect on shutdown

bit 0

GxASDCLC2: CWG Auto-shutdown on CLC2 Enable bit

1 = Shutdown when LC2OUT is high
0 = LC2OUT has no effect on shutdown

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 309

PIC16(L)F1508/9
REGISTER 26-4:
U-0

CWGxDBR: COMPLEMENTARY WAVEFORM GENERATOR (CWGx) RISING

DEAD-BAND COUNT REGISTER
U-0

R/W-x/u

CWGxDBR<5:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7-6

Unimplemented: Read as 0

bit 5-0

CWGxDBR<5:0>: Complementary Waveform Generator (CWGx) Rising counts

11 1111 = 63-64 counts of dead band
11 1110 = 62-63 counts of dead band

00 0010 = 2-3 counts of dead band

00 0001 = 1-2 counts of dead band
00 0000 = 0 counts of dead band

CWGxDBF: COMPLEMENTARY WAVEFORM GENERATOR (CWGx) FALLING

DEAD-BAND COUNT REGISTER

U-0

R/W-x/u

CWGxDBF<5:0>

bit 7

bit 0

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as 0

u = Bit is unchanged

x = Bit is unknown

-n/n = Value at POR and BOR/Value at all other Resets

1 = Bit is set

0 = Bit is cleared

q = Value depends on condition

bit 7-6

Unimplemented: Read as 0

bit 5-0

CWGxDBF<5:0>: Complementary Waveform Generator (CWGx) Falling counts

11 1111 = 63-64 counts of dead band
11 1110 = 62-63 counts of dead band

00 0010 = 2-3 counts of dead band

00 0001 = 1-2 counts of dead band
00 0000 = 0 counts of dead band. Dead-band generation is bypassed.

DS41609A-page 310

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 26-1:
Name
ANSELA
CWG1CON0
CWG1CON1
CWG1CON2
CWG1DBF
CWG1DBR

SUMMARY OF REGISTERS ASSOCIATED WITH CWG

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ANSA4

ANSA2

ANSA1

ANSA0

115

G1EN

G1OEB

G1OEA

G1POLB

G1POLA

G1CS0

307

G1ASDC2

G1ASDC1

G1ASDLB<1:0>

G1ASDLA<1:0>

G1ASDSFLT

G1ASDSCLC2

308
309

G1ASE

G1ARSEN

CWG1DBF<5:0>

310

CWG1DBR<5:0>

310

TRISA

TRISA5

TRISA4

TRISC

TRISC7

TRISC6

TRISC5

TRISC4

Legend:
Note 1:

G1IS<1:0>

(1)

TRISC3

TRISA2

TRISA1

TRISA0

114

TRISC2

TRISC1

TRISC0

122

x = unknown, u = unchanged, = unimplemented locations read as 0. Shaded cells are not used by CWG.
Unimplemented, read as 1.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 311

PIC16(L)F1508/9
NOTES:

DS41609A-page 312

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
27.0

IN-CIRCUIT SERIAL
PROGRAMMING (ICSP)

27.3

ICSP programming allows customers to manufacture

circuit boards with unprogrammed devices. Programming
can be done after the assembly process allowing the
device to be programmed with the most recent firmware
or a custom firmware. Five pins are needed for ICSP
programming:
ICSPCLK
ICSPDAT
MCLR/VPP
VDD
VSS

Connection to a target device is typically done through

an ICSP header. A commonly found connector on
development tools is the RJ-11 in the 6P6C (6 pin, 6
connector) configuration. See Figure 27-1.

FIGURE 27-1:

VDD

In Program/Verify mode the Program Memory, User IDs

and the Configuration Words are programmed through
serial communications. The ICSPDAT pin is a bidirectional I/O used for transferring the serial data and the
ICSPCLK pin is the clock input. For more information on
ICSP refer to the PIC12(L)F1501/PIC16(L)F150X
Memory Programming Specification (DS41573).

27.1

The Low-Voltage Programming Entry mode allows the

PIC Flash MCUs devices to be programmed using VDD
only, without high voltage. When the LVP bit of
Configuration Words is set to 1, the low-voltage ICSP
programming entry is enabled. To disable the
Low-Voltage ICSP mode, the LVP bit must be
programmed to 0.

ICSPDAT
NC
2 4 6
ICSPCLK
1 3 5
Target
VSS

PC Board
Bottom Side

Pin Description*
1 = VPP/MCLR

High-Voltage Programming Entry

Mode

Low-Voltage Programming Entry

Mode

ICD RJ-11 STYLE

CONNECTOR INTERFACE

VPP/MCLR

2 = VDD Target
3 = VSS (ground)
4 = ICSPDAT

The device is placed into High-Voltage Programming

Entry mode by holding the ICSPCLK and ICSPDAT
pins low then raising the voltage on MCLR/VPP to VIHH.

27.2

Common Programming Interfaces

5 = ICSPCLK
6 = No Connect

Another connector often found in use with the PICkit

programmers is a standard 6-pin header with 0.1 inch
spacing. Refer to Figure 27-2.

Entry into the Low-Voltage Programming Entry mode

requires the following steps:
1.
2.

MCLR is brought to VIL.

A 32-bit key sequence is presented on
ICSPDAT, while clocking ICSPCLK.

Once the key sequence is complete, MCLR must be

held at VIL for as long as Program/Verify mode is to be
maintained.
If low-voltage programming is enabled (LVP = 1), the
MCLR Reset function is automatically enabled and
cannot be disabled. See Section 6.4 MCLR for more
information.
The LVP bit can only be reprogrammed to 0 by using
the High-Voltage Programming mode.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 313

PIC16(L)F1508/9
FIGURE 27-2:

PICkit PROGRAMMER STYLE CONNECTOR INTERFACE

Pin 1 Indicator
Pin Description*
1 = VPP/MCLR

1
2
3
4
5
6

2 = VDD Target
3 = VSS (ground)
4 = ICSPDAT
5 = ICSPCLK
6 = No Connect

The 6-pin header (0.100" spacing) accepts 0.025" square pins.

For additional interface recommendations, refer to your

specific device programmer manual prior to PCB
design.
It is recommended that isolation devices be used to
separate the programming pins from other circuitry.
The type of isolation is highly dependent on the specific
application and may include devices such as resistors,
diodes, or even jumpers. See Figure 27-3 for more
information.

FIGURE 27-3:

TYPICAL CONNECTION FOR ICSP PROGRAMMING

External
Programming
Signals

Device to be
Programmed

VDD

VPP

MCLR/VPP

VSS

Data

ICSPDAT

Clock

ICSPCLK

To Normal Connections

* Isolation devices (as required).

DS41609A-page 314

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
28.0

INSTRUCTION SET SUMMARY

28.1

Read-Modify-Write Operations

Byte Oriented
Bit Oriented
Literal and Control

Any instruction that specifies a file register as part of

the instruction performs a Read-Modify-Write (R-M-W)
operation. The register is read, the data is modified,
and the result is stored according to either the instruction, or the destination designator d. A read operation
is performed on a register even if the instruction writes
to that register.

The literal and control category contains the most varied instruction word format.

TABLE 28-1:

Each PIC16 instruction is a 14-bit word containing the

operation code (opcode) and all required operands.
The op codes are broken into three broad categories.

Table 28-3 lists the instructions recognized by the

MPASMTM assembler.
All instructions are executed within a single instruction
cycle, with the following exceptions, which may take
two or three cycles:
Subroutine takes two cycles (CALL, CALLW)
Returns from interrupts or subroutines take two
cycles (RETURN, RETLW, RETFIE)
Program branching takes two cycles (GOTO, BRA,
BRW, BTFSS, BTFSC, DECFSZ, INCSFZ)
One additional instruction cycle will be used when
any instruction references an indirect file register
and the file select register is pointing to program
memory.
One instruction cycle consists of 4 oscillator cycles; for
an oscillator frequency of 4 MHz, this gives a nominal
instruction execution rate of 1 MHz.
All instruction examples use the format 0xhh to
represent a hexadecimal number, where h signifies a
hexadecimal digit.

OPCODE FIELD
DESCRIPTIONS

Field
f

Description

Register file address (0x00 to 0x7F)

Working register (accumulator)

Bit address within an 8-bit file register

Literal field, constant data or label

Dont care location (= 0 or 1).

The assembler will generate code with x = 0.
It is the recommended form of use for
compatibility with all Microchip software tools.

Destination select; d = 0: store result in W,

d = 1: store result in file register f.
Default is d = 1.

FSR or INDF number. (0-1)

Pre-post increment-decrement mode

selection

TABLE 28-2:

ABBREVIATION
DESCRIPTIONS

Field
PC

Program Counter

Time-out bit

C
DC
Z
PD

2011 Microchip Technology Inc.

Description

Preliminary

Carry bit
Digit carry bit
Zero bit
Power-down bit

DS41609A-page 315

PIC16(L)F1508/9
FIGURE 28-1:

GENERAL FORMAT FOR

INSTRUCTIONS

Byte-oriented file register operations

13
8 7 6
OPCODE
d
f (FILE #)

d = 0 for destination W
d = 1 for destination f
f = 7-bit file register address

Bit-oriented file register operations

13
10 9
7 6
OPCODE
b (BIT #)
f (FILE #)

b = 3-bit bit address

f = 7-bit file register address

Literal and control operations

General
13
OPCODE

0
k (literal)

k = 8-bit immediate value

CALL and GOTO instructions only

13
11 10
OPCODE

k (literal)

k = 11-bit immediate value

MOVLP instruction only

13
OPCODE

0
k (literal)

k = 7-bit immediate value

MOVLB instruction only

13
OPCODE

5 4

0
k (literal)

k = 5-bit immediate value

BRA instruction only

13
OPCODE

0
k (literal)

k = 9-bit immediate value

FSR Offset instructions

13
OPCODE

6
n

0
k (literal)

n = appropriate FSR
k = 6-bit immediate value

FSR Increment instructions

13
OPCODE

2 1
0
n m (mode)

n = appropriate FSR
m = 2-bit mode value
OPCODE only
13

0
OPCODE

DS41609A-page 316

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 28-3:

PIC16(L)F1508/9 ENHANCED INSTRUCTION SET

Mnemonic,
Operands

Description

Cycles

14-Bit Opcode
MSb

LSb

Status
Affected

Notes

BYTE-ORIENTED FILE REGISTER OPERATIONS

ADDWF
ADDWFC
ANDWF
ASRF
LSLF
LSRF
CLRF
CLRW
COMF
DECF
INCF
IORWF
MOVF
MOVWF
RLF
RRF
SUBWF
SUBWFB
SWAPF
XORWF

f, d
f, d
f, d
f, d
f, d
f, d
f

f, d
f, d
f, d
f, d
f, d
f
f, d
f, d
f, d
f, d
f, d
f, d

Add W and f
Add with Carry W and f
AND W with f
Arithmetic Right Shift
Logical Left Shift
Logical Right Shift
Clear f
Clear W
Complement f
Decrement f
Increment f
Inclusive OR W with f
Move f
Move W to f
Rotate Left f through Carry
Rotate Right f through Carry
Subtract W from f
Subtract with Borrow W from f
Swap nibbles in f
Exclusive OR W with f

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1

00
11
00
11
11
11
00
00
00
00
00
00
00
00
00
00
00
11
00
00

0111
1101
0101
0111
0101
0110
0001
0001
1001
0011
1010
0100
1000
0000
1101
1100
0010
1011
1110
0110

dfff
dfff
dfff
dfff
dfff
dfff
lfff
0000
dfff
dfff
dfff
dfff
dfff
1fff
dfff
dfff
dfff
dfff
dfff
dfff

ffff
ffff
ffff
ffff
ffff
ffff
ffff
00xx
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff

C, DC, Z
C, DC, Z
Z
C, Z
C, Z
C, Z
Z
Z
Z
Z
Z
Z
Z
C
C
C, DC, Z
C, DC, Z
Z

2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2

BYTE ORIENTED SKIP OPERATIONS

DECFSZ
INCFSZ

f, d
f, d

Decrement f, Skip if 0
Increment f, Skip if 0

BCF
BSF

f, b
f, b

Bit Clear f
Bit Set f

1(2)
1(2)

00
00

1, 2
1, 2

1011 dfff ffff

1111 dfff ffff

BIT-ORIENTED FILE REGISTER OPERATIONS

1
1

00bb bfff ffff

01bb bfff ffff

2
2

01
01

10bb bfff ffff

11bb bfff ffff

1, 2
1, 2

11
11
11
00
11
11
11
11

1110
1001
1000
0000
0001
0000
1100
1010

01
01

BIT-ORIENTED SKIP OPERATIONS

BTFSC
BTFSS

f, b
f, b

Bit Test f, Skip if Clear

Bit Test f, Skip if Set

ADDLW
ANDLW
IORLW
MOVLB
MOVLP
MOVLW
SUBLW
XORLW

k
k
k
k
k
k
k
k

Add literal and W

AND literal with W
Inclusive OR literal with W
Move literal to BSR
Move literal to PCLATH
Move literal to W
Subtract W from literal
Exclusive OR literal with W

1 (2)
1 (2)

LITERAL OPERATIONS
1
1
1
1
1
1
1
1

kkkk
kkkk
kkkk
001k
1kkk
kkkk
kkkk
kkkk

kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk

C, DC, Z
Z
Z

C, DC, Z
Z

Note 1: If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle
is executed as a NOP.
2: If this instruction addresses an INDF register and the MSb of the corresponding FSR is set, this instruction will require one
additional instruction cycle.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 317

PIC16(L)F1508/9
TABLE 28-3:

PIC16(L)F1508/9 ENHANCED INSTRUCTION SET (CONTINUED)

Mnemonic,
Operands

Description

Cycles

14-Bit Opcode
MSb

LSb

Status
Affected

Notes

CONTROL OPERATIONS
2
2
2
2
2
2
2
2

BRA
BRW
CALL
CALLW
GOTO
RETFIE
RETLW
RETURN

k
k
k

Relative Branch
Relative Branch with W
Call Subroutine
Call Subroutine with W
Go to address
Return from interrupt
Return with literal in W
Return from Subroutine

CLRWDT
NOP
OPTION
RESET
SLEEP
TRIS

Clear Watchdog Timer

No Operation
Load OPTION_REG register with W
Software device Reset
Go into Standby mode
Load TRIS register with W

ADDFSR
MOVIW

n, k
n mm

MOVWI

k[n]
n mm

Add Literal k to FSRn

Move Indirect FSRn to W with pre/post inc/dec
modifier, mm
Move INDFn to W, Indexed Indirect.
Move W to Indirect FSRn with pre/post inc/dec
modifier, mm
Move W to INDFn, Indexed Indirect.

11
00
10
00
10
00
11
00

001k
0000
0kkk
0000
1kkk
0000
0100
0000

kkkk
0000
kkkk
0000
kkkk
0000
kkkk
0000

kkkk
1011
kkkk
1010
kkkk
1001
kkkk
1000

00
00
00
00
00
00

0000
0000
0000
0000
0000
0000

0110
0000
0110
0000
0110
0110

0100 TO, PD
0000
0010
0001
0011 TO, PD
0fff

INHERENT OPERATIONS
1
1
1
1
1
1

C-COMPILER OPTIMIZED

k[n]

1
1

11
00

1
1

11
00

0001 0nkk kkkk

0000 0001 0nmm Z
kkkk
1111 0nkk 1nmm Z
0000 0001 kkkk

1111 1nkk

2, 3
2
2, 3
2

DS41609A-page 318

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
28.2

Instruction Descriptions

ADDFSR

Add Literal to FSRn

ANDLW

AND literal with W

Syntax:

[ label ] ADDFSR FSRn, k

Syntax:

[ label ] ANDLW

Operands:

-32 k 31
n [ 0, 1]

Operands:

0 k 255

Operation:

FSR(n) + k FSR(n)

Status Affected:

None

Description:

The signed 6-bit literal k is added to

the contents of the FSRnH:FSRnL
register pair.

Operation:

(W) .AND. (k) (W)

Status Affected:

Description:

The contents of W register are

ANDed with the eight-bit literal k.
The result is placed in the W register.

FSRn is limited to the range 0000h FFFFh. Moving beyond these bounds
will cause the FSR to wrap around.

ADDLW

Add literal and W

ANDWF

AND W with f

Syntax:

[ label ] ADDLW

Syntax:

[ label ] ANDWF

Operands:

0 f 127
d 0,1

Operation:

(W) .AND. (f) (destination)

Status Affected:

Description:

AND the W register with register f. If

d is 0, the result is stored in the W
register. If d is 1, the result is stored
back in register f.

ASRF

Arithmetic Right Shift

Operands:

0 k 255

Operation:

(W) + k (W)

Status Affected:

C, DC, Z

Description:

The contents of the W register are

added to the eight-bit literal k and the
result is placed in the W register.

f,d

ADDWF

Add W and f

Syntax:

[ label ] ADDWF

Syntax:

[ label ] ASRF

Operands:

0 f 127
d 0,1

Operands:

0 f 127
d [0,1]

Operation:

(W) + (f) (destination)

Operation:

(f<7>) dest<7>
(f<7:1>) dest<6:0>,
(f<0>) C,

f,d

Status Affected:

C, DC, Z

Description:

Add the contents of the W register

with register f. If d is 0, the result is
stored in the W register. If d is 1, the
result is stored back in register f.

ADDWFC

ADD W and CARRY bit to f

Syntax:

[ label ] ADDWFC

Operands:

0 f 127
d [0,1]

Status Affected:

C, Z

Description:

The contents of register f are shifted

one bit to the right through the Carry
flag. The MSb remains unchanged. If
d is 0, the result is placed in W. If d
is 1, the result is stored back in register f.
register f

f {,d}

Operation:

(W) + (f) + (C) dest

Status Affected:

C, DC, Z

Description:

Add W, the Carry flag and data memory location f. If d is 0, the result is
placed in W. If d is 1, the result is
placed in data memory location f.

2011 Microchip Technology Inc.

f {,d}

Preliminary

DS41609A-page 319

PIC16(L)F1508/9
BCF

Bit Clear f

Syntax:

[ label ] BCF

f,b

BTFSC

Bit Test f, Skip if Clear

Syntax:

[ label ] BTFSC f,b

0 f 127
0b7

Operands:

0 f 127
0b7

Operands:

Operation:

0 (f<b>)

Operation:

skip if (f<b>) = 0

Status Affected:

None

Status Affected:

None

Description:

Bit b in register f is cleared.

Description:

If bit b in register f is 1, the next

instruction is executed.
If bit b, in register f, is 0, the next
instruction is discarded, and a NOP is
executed instead, making this a
2-cycle instruction.

BRA

Relative Branch

BTFSS

Bit Test f, Skip if Set

Syntax:

[ label ] BRA label

[ label ] BRA $+k

Syntax:

[ label ] BTFSS f,b

Operands:

-256 label - PC + 1 255

-256 k 255

0 f 127
0b<7

Operation:

skip if (f<b>) = 1

Operation:

(PC) + 1 + k PC

Status Affected:

None

Status Affected:

None

Description:

Add the signed 9-bit literal k to the

PC. Since the PC will have incremented to fetch the next instruction,
the new address will be PC + 1 + k.
This instruction is a two-cycle instruction. This branch has a limited range.

If bit b in register f is 0, the next

instruction is executed.
If bit b is 1, then the next
instruction is discarded and a NOP is
executed instead, making this a
2-cycle instruction.

BRW

Relative Branch with W

Syntax:

[ label ] BRW

Operands:

None

Operation:

(PC) + (W) PC

Status Affected:

None

Description:

Add the contents of W (unsigned) to

the PC. Since the PC will have incremented to fetch the next instruction,
the new address will be PC + 1 + (W).
This instruction is a two-cycle instruction.

BSF

Bit Set f

Syntax:

[ label ] BSF

Operands:

0 f 127
0b7

Operation:

1 (f<b>)

Status Affected:

None

Description:

Bit b in register f is set.

DS41609A-page 320

f,b

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
CALL

Call Subroutine

CLRWDT

Clear Watchdog Timer

Syntax:

[ label ] CALL k

Syntax:

[ label ] CLRWDT

Operands:

0 k 2047

Operands:

None

Operation:

(PC)+ 1 TOS,
k PC<10:0>,
(PCLATH<4:3>) PC<12:11>

Operation:

Status Affected:

None

00h WDT
0 WDT prescaler,
1 TO
1 PD

Description:

Call Subroutine. First, return address

(PC + 1) is pushed onto the stack.
The eleven-bit immediate address is
loaded into PC bits <10:0>. The upper
bits of the PC are loaded from
PCLATH. CALL is a two-cycle instruction.

Status Affected:

TO, PD

Description:

CLRWDT instruction resets the Watchdog Timer. It also resets the prescaler
of the WDT.
Status bits TO and PD are set.

CALLW

Subroutine Call With W

COMF

Complement f

Syntax:

[ label ] CALLW

Syntax:

[ label ] COMF

Operands:

None

Operands:

Operation:

(PC) +1 TOS,
(W) PC<7:0>,
(PCLATH<6:0>) PC<14:8>

0 f 127
d [0,1]

Operation:

(f) (destination)

Status Affected:

Description:

The contents of register f are complemented. If d is 0, the result is

stored in W. If d is 1, the result is
stored back in register f.

DECF

Decrement f

Syntax:

[ label ] DECF f,d

Status Affected:

None

Description:

Subroutine call with W. First, the

return address (PC + 1) is pushed
onto the return stack. Then, the contents of W is loaded into PC<7:0>,
and the contents of PCLATH into
PC<14:8>. CALLW is a two-cycle
instruction.

CLRF

Clear f

Syntax:

[ label ] CLRF

f,d

Operands:

0 f 127

Operands:

Operation:

00h (f)
1Z

0 f 127
d [0,1]

Operation:

(f) - 1 (destination)

Status Affected:

Description:

The contents of register f are cleared

and the Z bit is set.

Description:

Decrement register f. If d is 0, the

result is stored in the W
register. If d is 1, the result is stored
back in register f.

CLRW

Clear W

Syntax:

[ label ] CLRW

Operands:

None

Operation:

00h (W)
1Z

Status Affected:

Description:

W register is cleared. Zero bit (Z) is

set.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 321

PIC16(L)F1508/9
DECFSZ

Decrement f, Skip if 0

INCFSZ

Increment f, Skip if 0

Syntax:

[ label ] DECFSZ f,d

Syntax:

[ label ]

Operands:

0 f 127
d [0,1]

Operands:

0 f 127
d [0,1]

Operation:

(f) - 1 (destination);
skip if result = 0

Operation:

(f) + 1 (destination),
skip if result = 0

Status Affected:

None

Status Affected:

None

Description:

The contents of register f are decremented. If d is 0, the result is placed

in the W register. If d is 1, the result
is placed back in register f.
If the result is 1, the next instruction is
executed. If the result is 0, then a
NOP is executed instead, making it a
2-cycle instruction.

Description:

The contents of register f are incremented. If d is 0, the result is placed

in the W register. If d is 1, the result
is placed back in register f.
If the result is 1, the next instruction is
executed. If the result is 0, a NOP is
executed instead, making it a 2-cycle
instruction.

GOTO

Unconditional Branch

IORLW

Inclusive OR literal with W

Syntax:

[ label ]

Syntax:

[ label ]

GOTO k

INCFSZ f,d

IORLW k

Operands:

0 k 2047

Operands:

0 k 255

Operation:

k PC<10:0>
PCLATH<4:3> PC<12:11>

Operation:

(W) .OR. k (W)

Status Affected:

None

Description:

GOTO is an unconditional branch. The

eleven-bit immediate value is loaded
into PC bits <10:0>. The upper bits of
PC are loaded from PCLATH<4:3>.
GOTO is a two-cycle instruction.

The contents of the W register are

ORed with the eight-bit literal k. The
result is placed in the W register.

INCF

Increment f

IORWF

Inclusive OR W with f

Syntax:

[ label ]

Syntax:

[ label ]

Operands:

0 f 127
d [0,1]

Operands:

0 f 127
d [0,1]

Operation:

(f) + 1 (destination)

Operation:

(W) .OR. (f) (destination)

Status Affected:

Description:

The contents of register f are incremented. If d is 0, the result is placed

in the W register. If d is 1, the result
is placed back in register f.

Description:

Inclusive OR the W register with register f. If d is 0, the result is placed in

the W register. If d is 1, the result is
placed back in register f.

DS41609A-page 322

INCF f,d

Preliminary

IORWF

f,d

2011 Microchip Technology Inc.

PIC16(L)F1508/9
LSLF

Logical Left Shift

f {,d}

MOVF

Move f

Syntax:

[ label ] LSLF

Syntax:

[ label ]

Operands:

0 f 127
d [0,1]

Operands:

0 f 127
d [0,1]

Operation:

(f<7>) C
(f<6:0>) dest<7:1>
0 dest<0>

Operation:

(f) (dest)

Status Affected:

C, Z

Description:

The contents of register f are shifted

one bit to the left through the Carry flag.
A 0 is shifted into the LSb. If d is 0,
the result is placed in W. If d is 1, the
result is stored back in register f.
C

Status Affected:

Description:

The contents of register f is moved to

a destination dependent upon the
status of d. If d = 0,
destination is W register. If d = 1, the
destination is file register f itself. d = 1
is useful to test a file register since
status flag Z is affected.

Words:

Cycles:

Example:

Logical Right Shift

Syntax:

[ label ] LSRF

Operands:

0 f 127
d [0,1]

Operation:

0 dest<7>
(f<7:1>) dest<6:0>,
(f<0>) C,

Status Affected:

C, Z

Description:

The contents of register f are shifted

one bit to the right through the Carry
flag. A 0 is shifted into the MSb. If d is
0, the result is placed in W. If d is 1,
the result is stored back in register f.

2011 Microchip Technology Inc.

f {,d}

MOVF

FSR, 0

After Instruction
W = value in FSR register
Z = 1

LSRF

MOVF f,d

Preliminary

DS41609A-page 323

PIC16(L)F1508/9
MOVIW

Move INDFn to W

Syntax:

[ label ] MOVIW ++FSRn

[ label ] MOVIW --FSRn
[ label ] MOVIW FSRn++
[ label ] MOVIW FSRn-[ label ] MOVIW k[FSRn]

Operands:

n [0,1]
mm [00,01, 10, 11]
-32 k 31

Operation:

INDFn W
Effective address is determined by
FSR + 1 (preincrement)
FSR - 1 (predecrement)
FSR + k (relative offset)
After the Move, the FSR value will be
either:
FSR + 1 (all increments)
FSR - 1 (all decrements)
Unchanged

Status Affected:

MOVLP

Move literal to PCLATH

Syntax:

[ label ] MOVLP k

Operands:

0 k 127

Operation:

k PCLATH

Status Affected:

None

Description:

The seven-bit literal k is loaded into the

PCLATH register.

MOVLW

Move literal to W

Syntax:

[ label ]

Operands:

0 k 255

Operation:

k (W)

Status Affected:

None

Description:

The eight-bit literal k is loaded into W

Words:

1
1

Mode

Syntax

Cycles:

Preincrement

++FSRn

Example:

Predecrement

--FSRn

Postincrement

FSRn++

Postdecrement

FSRn--

Description:

Note: The INDFn registers are not

physical registers. Any instruction that
accesses an INDFn register actually
accesses the register at the address
specified by the FSRn.

Syntax:

[ label ] MOVLB k

Operands:

0 k 15

Operation:

k BSR

Status Affected:

None

Description:

The five-bit literal k is loaded into the

Bank Select Register (BSR).

DS41609A-page 324

0x5A

MOVWF

Move W to f

Syntax:

[ label ]

MOVWF

Operands:

0 f 127

Operation:

(W) (f)

0x5A

Status Affected:

None

Description:

Move data from W register to register

Words:

Cycles:

Example:

FSRn is limited to the range 0000h FFFFh. Incrementing/decrementing it

beyond these bounds will cause it to
wrap-around.

Move literal to BSR

MOVLW

After Instruction
W =

This instruction is used to move data

between W and one of the indirect
registers (INDFn). Before/after this
move, the pointer (FSRn) is updated by
pre/post incrementing/decrementing it.

MOVLB

MOVLW k

Preliminary

MOVWF

OPTION_REG

Before Instruction
OPTION_REG =
W
=
After Instruction
OPTION_REG =
W
=

0xFF
0x4F
0x4F
0x4F

2011 Microchip Technology Inc.

PIC16(L)F1508/9
MOVWI

Move W to INDFn

Syntax:

[ label ] MOVWI ++FSRn

[ label ] MOVWI --FSRn
[ label ] MOVWI FSRn++
[ label ] MOVWI FSRn-[ label ] MOVWI k[FSRn]

Operands:

Operation:

Status Affected:

n [0,1]
mm [00,01, 10, 11]
-32 k 31
W INDFn
Effective address is determined by
FSR + 1 (preincrement)
FSR - 1 (predecrement)
FSR + k (relative offset)
After the Move, the FSR value will be
either:
FSR + 1 (all increments)
FSR - 1 (all decrements)
Unchanged
None

Mode

Syntax

Preincrement

++FSRn

Predecrement

--FSRn

Postincrement

FSRn++

Postdecrement

FSRn--

Description:

This instruction is used to move data

between W and one of the indirect
registers (INDFn). Before/after this
move, the pointer (FSRn) is updated by
pre/post incrementing/decrementing it.

Note: The INDFn registers are not

physical registers. Any instruction that
accesses an INDFn register actually
accesses the register at the address
specified by the FSRn.

NOP

No Operation

Syntax:

[ label ]

Operands:

None

Operation:

No operation

Status Affected:

None

Description:

No operation.

Words:

Cycles:

Example:

NOP

OPTION

Load OPTION_REG Register

with W

Syntax:

[ label ] OPTION

Operands:

None

Operation:

(W) OPTION_REG

Status Affected:

None

Description:

Move data from W register to

OPTION_REG register.

RESET

Software Reset

Syntax:

[ label ] RESET

Operands:

None

Operation:

Execute a device Reset. Resets the

nRI flag of the PCON register.

Status Affected:

None

Description:

This instruction provides a way to

execute a hardware Reset by software.

FSRn is limited to the range 0000h FFFFh. Incrementing/decrementing it

beyond these bounds will cause it to
wrap-around.
The increment/decrement operation on
FSRn WILL NOT affect any Status bits.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 325

PIC16(L)F1508/9
RETFIE

Return from Interrupt

Syntax:

[ label ]

RETURN

RETFIE

Return from Subroutine

Syntax:

[ label ]
None

RETURN

Operands:

None

Operands:

Operation:

TOS PC,
1 GIE

Operation:

TOS PC

Status Affected:

None

Status Affected:

None

Description:

Return from Interrupt. Stack is POPed

and Top-of-Stack (TOS) is loaded in
the PC. Interrupts are enabled by
setting Global Interrupt Enable bit,
GIE (INTCON<7>). This is a two-cycle
instruction.

Return from subroutine. The stack is

POPed and the top of the stack (TOS)
is loaded into the program counter.
This is a two-cycle instruction.

Words:

Cycles:

Example:

RETFIE
After Interrupt
PC =
GIE =

TOS
1

RETLW

Return with literal in W

Syntax:

[ label ]

Operands:

0 k 255

Operation:

k (W);
TOS PC

Status Affected:

None

Description:

The W register is loaded with the eight

bit literal k. The program counter is
loaded from the top of the stack (the
return address). This is a two-cycle
instruction.

Words:

Cycles:

Example:

TABLE

RETLW k

Rotate Left f through Carry

Syntax:

[ label ]

Operands:

0 f 127
d [ 0, 1]

Operation:

See description below

Status Affected:

Description:

The contents of register f are rotated

one bit to the left through the Carry
flag. If d is 0, the result is placed in
the W register. If d is 1, the result is
stored back in register f.

RLF

CALL TABLE;W contains table

;offset value

;W now has table value

ADDWF PC ;W = offset
RETLW k1 ;Begin table
RETLW k2 ;

RETLW kn ; End of table

Before Instruction
W =
After Instruction
W =

DS41609A-page 326

RLF

Words:

Cycles:

Example:

RLF

f,d

REG1,0

Before Instruction
REG1
C
After Instruction
REG1
W
C

=
=

1110 0110
0

=
=
=

1110 0110
1100 1100
1

0x07
value of k8

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
SUBLW

Subtract W from literal

Syntax:

[ label ]

RRF

Rotate Right f through Carry

Syntax:

[ label ]

Operands:

0 f 127
d [0,1]

Operation:

See description below

Status Affected:

C, DC, Z

Status Affected:

Description:

The contents of register f are rotated

one bit to the right through the Carry
flag. If d is 0, the result is placed in
the W register. If d is 1, the result is
placed back in register f.

The W register is subtracted (2s complement method) from the eight-bit

literal k. The result is placed in the W
register.

RRF f,d

SUBLW k

Operands:

0 k 255

Operation:

k - (W) W)

C=0

C=1

DC = 0

W<3:0> k<3:0>

DC = 1

W<3:0> k<3:0>

SLEEP

Enter Sleep mode

SUBWF

Subtract W from f

Syntax:

[ label ]

Syntax:

[ label ]

Operands:

0 f 127
d [0,1]

Operation:

(f) - (W) destination)

Status Affected:

C, DC, Z

Description:

Subtract (2s complement method) W

register from register f. If d is 0, the
result is stored in the W
register. If d is 1, the result is stored
back in register f.

SLEEP

Operands:

None

Operation:

00h WDT,
0 WDT prescaler,
1 TO,
0 PD

Status Affected:

TO, PD

Description:

The power-down Status bit, PD is

cleared. Time-out Status bit, TO is
set. Watchdog Timer and its prescaler are cleared.
The processor is put into Sleep mode
with the oscillator stopped.

2011 Microchip Technology Inc.

SUBWF f,d

C=0

C=1

DC = 0

W<3:0> f<3:0>

DC = 1

W<3:0> f<3:0>

SUBWFB

Subtract W from f with Borrow

Syntax:

SUBWFB

Operands:

0 f 127
d [0,1]

Operation:

(f) (W) (B) dest

f {,d}

Status Affected:

C, DC, Z

Description:

Subtract W and the BORROW flag

(CARRY) from register f (2s complement method). If d is 0, the result is
stored in W. If d is 1, the result is
stored back in register f.

Preliminary

DS41609A-page 327

PIC16(L)F1508/9
SWAPF

Swap Nibbles in f

XORLW

Exclusive OR literal with W

Syntax:

[ label ]

Syntax:

[ label ]

Operands:

0 f 127
d [0,1]

Operation:

SWAPF f,d

(f<3:0>) (destination<7:4>),
(f<7:4>) (destination<3:0>)

XORLW k

Operands:

0 k 255

Operation:

(W) .XOR. k W)

Status Affected:

Description:

The contents of the W register are

XORed with the eight-bit
literal k. The result is placed in the
W register.

Status Affected:

None

Description:

The upper and lower nibbles of register f are exchanged. If d is 0, the

result is placed in the W register. If d
is 1, the result is placed in register f.

TRIS

Load TRIS Register with W

XORWF

Exclusive OR W with f

Syntax:

[ label ] TRIS f

Syntax:

[ label ]

Operands:

5f7

Operands:

Operation:

(W) TRIS register f

0 f 127
d [0,1]

Status Affected:

None

Operation:

(W) .XOR. (f) destination)

Status Affected:

Description:

Exclusive OR the contents of the W

register with register f. If d is 0, the
result is stored in the W register. If d
is 1, the result is stored back in register f.

Description:

DS41609A-page 328

Move data from W register to TRIS

Preliminary

XORWF

f,d

2011 Microchip Technology Inc.

PIC16(L)F1508/9
29.0

ELECTRICAL SPECIFICATIONS

Absolute Maximum Ratings()

Ambient temperature under bias....................................................................................................... -40C to +125C
Storage temperature ........................................................................................................................ -65C to +150C
Voltage on VDD with respect to VSS, PIC16F1508/9 .......................................................................... -0.3V to +6.5V
Voltage on VDD with respect to VSS, PIC16LF1508/9 ........................................................................ -0.3V to +4.0V
Voltage on MCLR with respect to Vss ................................................................................................. -0.3V to +9.0V
Voltage on all other pins with respect to VSS ........................................................................... -0.3V to (VDD + 0.3V)
Total power dissipation(1) ............................................................................................................................... 800 mW
Maximum current out of VSS pin, -40C TA +85C for industrial............................................................... 396 mA
Maximum current out of VSS pin, -40C TA +125C for extended ............................................................ 114 mA
Maximum current into VDD pin, -40C TA +85C for industrial.................................................................. 292 mA
Maximum current into VDD pin, -40C TA +125C for extended ............................................................... 107 mA
Clamp current, IK (VPIN < 0 or VPIN > VDD) 20 mA
Maximum output current sunk by any I/O pin.................................................................................................... 25 mA
Maximum output current sourced by any I/O pin .............................................................................................. 25 mA
Note 1:

Power dissipation is calculated as follows: PDIS = VDD x {IDD IOH} + {(VDD VOH) x IOH} + (VOl x
IOL).

NOTICE: Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operation listings of this specification is not implied. Exposure above maximum rating conditions for
extended periods may affect device reliability.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 329

PIC16(L)F1508/9
PIC16F1508/9 VOLTAGE FREQUENCY GRAPH, -40C TA +125C

FIGURE 29-1:

VDD (V)

5.5

2.5
2.3

Frequency (MHz)
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.
2: Refer to Table 29-1 for each Oscillator modes supported frequencies.

PIC16LF1508/9 VOLTAGE FREQUENCY GRAPH, -40C TA +125C

VDD (V)

FIGURE 29-2:

3.6

2.5

1.8
0

Frequency (MHz)

Note 1: The shaded region indicates the permissible combinations of voltage and frequency.
2: Refer to Table 29-1 for each Oscillator modes supported frequencies.

DS41609A-page 330

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
29.1

DC Characteristics: PIC16(L)F1508/9-I/E (Industrial, Extended)

PIC16LF1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

PIC16F1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

Param.
No.
D001

Sym.
VDD

Characteristic

VDR

VPOR*

VPORR*

Units

PIC16LF1508/9

1.8
2.5

3.6
3.6

V
V

FOSC 16 MHz
FOSC 20 MHz

PIC16F1508/9

2.3
2.5

5.5
5.5

V
V

FOSC 16 MHz
FOSC 20 MHz

PIC16LF1508/9

1.5

Device in Sleep mode

PIC16F1508/9

1.7

Device in Sleep mode

PIC16LF1508/9

1.6

PIC16F1508/9

1.7

V
V

Power-on Reset Rearm Voltage

PIC16LF1508/9

0.8

PIC16F1508/9

1.65

Fixed Voltage Reference Voltage for

ADC, Initial Accuracy

1
1
1
1
1
1

D003C* TCVFVR

Temperature Coefficient, Fixed

Voltage Reference

-130

ppm/C

D003D* VFVR/
VIN

Line Regulation, Fixed Voltage

Reference

0.270

%/V

D004*

VDD Rise Rate to ensure internal

Power-on Reset signal

0.05

V/ms

D002B
D003

VADFVR

SVDD

Conditions

Power-on Reset Release Voltage

D002A
D002B

Max.

RAM Data Retention Voltage(1)

D002*
D002A

Typ

Supply Voltage

D001
D002*

Min.

1.024V, VDD 2.5V, 85C (NOTE 2)

1.024V, VDD 2.5V, 125C (NOTE 2)
2.048V, VDD 2.5V, 85C
2.048V, VDD 2.5V, 125C
4.096V, VDD 4.75V, 85C
4.096V, VDD 4.75V, 125C

See Section 6.1 Power-on Reset

(POR) for details.

Note

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not
tested.
1: This is the limit to which VDD can be lowered in Sleep mode without losing RAM data.
2: For proper operation, the minimum value of the ADC positive voltage reference must be 1.8V or greater. When selecting
the FVR or the VREF+ pin as the source of the ADC positive voltage reference, be aware that the voltage must be 1.8V or
greater.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 331

PIC16(L)F1508/9
FIGURE 29-3:

POR AND POR REARM WITH SLOW RISING VDD

VDD
VPOR
VPORR

VSS
NPOR

POR REARM
VSS
TVLOW(2)

Note 1:
2:
3:

DS41609A-page 332

TPOR(3)

When NPOR is low, the device is held in Reset.

TPOR 1 s typical.
TVLOW 2.7 s typical.

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
29.2

DC Characteristics: PIC16(L)F1508/9-I/E (Industrial, Extended)

PIC16LF1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

PIC16F1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

Param
No.

Device
Characteristics

Conditions

Min.

Typ

Max.

Units

1.8

3.0

2.3

3.0

5.0

110

1.8

170

3.0

110

200

2.3

130

250

3.0

VDD

Note

Supply Current (IDD)(1, 2)

D010
D010

D011
D011

D012
D012

D013
D013

D014

D015
D015

160

340

5.0

120

290

1.8

220

480

3.0

230

300

2.3

300

500

3.0

350

700

5.0

140

1.8

230

3.0

180

2.3

240

3.0

115

320

5.0

100

250

2.3

180

430

3.0

160

275

2.3

210

450

3.0

240

500

5.0

2.3

1.8

4.0

300

3.0

100

2.3

280

3.0

400

5.0

FOSC = 32 kHz LP Oscillator mode

FOSC = 1 MHz XT Oscillator mode

FOSC = 4 MHz XT Oscillator mode

FOSC = 1 MHz
EC Oscillator mode, Medium-power mode
FOSC = 1 MHz
EC Oscillator mode
Medium-power mode
FOSC = 4 MHz
EC Oscillator mode,
Medium-power mode
FOSC = 4 MHz
EC Oscillator mode
Medium-power mode
FOSC = 31 kHz
LFINTOSC mode
FOSC = 31 kHz
LFINTOSC mode

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: The test conditions for all IDD measurements in active operation mode are: CLKIN = external square wave, from
rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading
and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current
consumption.
3: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended
by the formula IR = VDD/2REXT (mA) with REXT in k.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 333

PIC16(L)F1508/9
29.2

DC Characteristics: PIC16(L)F1508/9-I/E (Industrial, Extended) (Continued)

PIC16LF1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

PIC16F1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

Param
No.

Device
Characteristics

D016
D016

D017*
D017*

Conditions

Min.

Typ

Max.

Units

220

400

1.8

280

600

3.0

280

400

2.3

310

550

3.0

360

750

5.0

380

700

1.8

560

1100

3.0

490

850

2.3

600

1150

3.0

VDD

Note
FOSC = 500 kHz HFINTOSC mode
FOSC = 500 kHz HFINTOSC mode

FOSC = 8 MHz
HFINTOSC mode
FOSC = 8 MHz
HFINTOSC mode

690

1350

5.0

520

1200

1.8

810

1750

3.0

680

1200

2.3

850

1800

3.0

960

2000

5.0

D019A

750

2100

3.0

FOSC = 20 MHz
ECH mode

D019A

790

2100

3.0

810

2400

5.0

FOSC = 20 MHz
ECH mode

D019B

1.8

FOSC = 32 kHz ECL mode

3.0

2.3

3.0

5.0

1.8

3.0

2.3

3.0

D018
D018

D019B

D019C
D019C

D020
D020

100

5.0

150

350

1.8

280

680

3.0

230

350

2.3

310

680

3.0

370

830

5.0

FOSC = 16 MHz
HFINTOSC mode
FOSC = 16 MHz
HFINTOSC mode

FOSC = 32 kHz ECL mode

FOSC = 500 kHz ECL mode

FOSC = 4 MHz EXTRC mode (Note 3)

These parameters are characterized but not tested.

DS41609A-page 334

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
29.2

DC Characteristics: PIC16(L)F1508/9-I/E (Industrial, Extended) (Continued)

PIC16LF1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

PIC16F1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

Param
No.

Device
Characteristics

Conditions

Min.

Typ

Max.

Units

D021

1000

2100

3.0

FOSC = 20 MHz HS Oscillator mode

D021

1350

2100

3.0

FOSC = 20 MHz HS Oscillator mode

1700

2400

5.0

VDD

Note

These parameters are characterized but not tested.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 335

PIC16(L)F1508/9
29.3

DC Characteristics: PIC16(L)F1508/9-I/E (Power-Down)

PIC16LF1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

PIC16F1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

Param
No.

Device Characteristics
Power-down Current

D022

D022A

D023
D023

D023A
D023A

Min.

Typ

Max.
+85C

Max.
+125C

Units

0.025

1.0

7.0

0.035

2.0

0.20

0.25

Conditions
VDD

Note

1.8

9.0

3.0

Base Current: WDT, BOR, FVR,

and SOSC disabled, all Peripherals inactive

2.0

2.3

4.0

3.0

0.30

5.0

2.3

3.0

5.0

0.29

1.5

1.8

0.39

2.0

3.0

10.5

2.3

11.3

3.0

12.5

5.0

1.8

3.0

2.3

3.0
5.0

(IPD)(2)

WDT, BOR, FVR, and SOSC disabled, all Peripherals inactive

(VREGPM = 1; Low-Power mode)
Base Current: WDT, BOR, FVR
and SOSC disabled, all peripheral
inactive (VREGPM = 0; Normal
Power mode)
LPWDT Current (Note 1)
LPWDT Current (Note 1)

FVR current (Note 1)

115

120

D024

3.0

BOR Current (Note 1)

D024

3.0

BOR Current (Note 1)

5.0

D24A

0.1

3.0

LPBOR Current (Note 1)

D24A

3.0

LPBOR Current (Note 1)

5.0

Note 1:

2:
3:

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are
not tested.
The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is
enabled. The peripheral current can be determined by subtracting the base IDD or IPD current from this limit. Max
values should be used when calculating total current consumption.
The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD.
A/D oscillator source is FRC.

DS41609A-page 336

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
29.3

DC Characteristics: PIC16(L)F1508/9-I/E (Power-Down) (Continued)

PIC16LF1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

PIC16F1508/9

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +85C for industrial
-40C TA +125C for extended

Param
No.

Device Characteristics

D025
D025

D026
D026

D026A*
D026A*

D027
D027

Note 1:

2:
3:

Min.

Typ

Max.
+85C

0.6

1.8

Conditions

Max.
+125C

Units

3.5

1.8

4.0

3.0

2.3

3.0

5.0

.025

1.8

.035

3.0

2.3

3.0

VDD

5.0

250

1.8

250

3.0

280

2.3

280

3.0

280

5.0

1.8

3.0

2.3

3.0

5.0

Note
SOSC Current (Note 1)
SOSC Current (Note 1)

A/D Current (Note 1, Note 3), no

conversion in progress
A/D Current (Note 1, Note 3), no
conversion in progress

A/D Current (Note 1, Note 3),

conversion in progress
A/D Current (Note 1, Note 3),
conversion in progress

Comparator, Low-Power mode

(Note 1)
Comparator, Low-Power mode
(Note 1)

These parameters are characterized but not tested.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 337

PIC16(L)F1508/9
29.4

DC Characteristics: PIC16(L)F1508/9-I/E
DC CHARACTERISTICS

Param
No.

Sym.
VIL

Characteristic

Standard Operating Conditions (unless otherwise stated)

Operating temperature -40C TA +85C for industrial
-40C TA +125C for extended
Min.

Typ

Max.

Units

Conditions

Input Low Voltage

I/O PORT:

D030

with TTL buffer

D030A
D031

with Schmitt Trigger buffer

D032

MCLR
VIH

0.8

4.5V VDD 5.5V

0.15 VDD

1.8V VDD 4.5V

0.2 VDD

2.0V VDD 5.5V

0.2 VDD

Input High Voltage

I/O ports:

D040

with TTL buffer

D040A
D041

with Schmitt Trigger buffer

D042

MCLR
IIL

2.0

4.5V VDD 5.5V

0.25 VDD +
0.8

1.8V VDD 4.5V

2.0V VDD 5.5V

0.8 VDD

V
nA

Input Leakage Current(1)

D060

I/O ports

125

1000

VSS VPIN VDD, Pin at highimpedance at 85C

125C

D061

MCLR(2)

200

VSS VPIN VDD at 85C

25
25

100
140

200
300

VDD = 3.3V, VPIN = VSS

VDD = 5.0V, VPIN = VSS

0.6

IOL = 8mA, VDD = 5V

IOL = 6mA, VDD = 3.3V
IOL = 1.8mA, VDD = 1.8V

VDD - 0.7

IOH = 3.5mA, VDD = 5V

IOH = 3mA, VDD = 3.3V
IOH = 1mA, VDD = 1.8V

IPUR

Weak Pull-up Current

D070*
VOL
D080

Output Low Voltage(3)

I/O ports

VOH
D090

Output High Voltage(3)

I/O ports

Capacitive Loading Specs on Output Pins

D101A* CIO

All I/O pins

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: Negative current is defined as current sourced by the pin.
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent
normal operating conditions. Higher leakage current may be measured at different input voltages.
3: Including OSC2 in CLKOUT mode.

DS41609A-page 338

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
29.5

Memory Programming Requirements

Standard Operating Conditions (unless otherwise stated)
Operating temperature -40C TA +125C

DC CHARACTERISTICS
Param
No.

Sym.

Characteristic

Min.

Typ

Max.

Units

Conditions

Program Memory
Programming Specifications
D110

VIHH

Voltage on MCLR/VPP pin

8.0

9.0

D111

IDDP

Supply Current during

Programming

(Note 2)

D112

VBE

VDD for Bulk Erase

2.7

VDD max.

D113

VPEW

VDD for Write or Row Erase

VDD min.

VDD max.

D114

IPPPGM Current on MCLR/VPP during Erase/

Write

1.0

D115

IDDPGM Current on VDD during Erase/Write

5.0

D121

Cell Endurance

10K

E/W

VDD min.

VDD max.

2.5

Year

Provided no other
specifications are violated

100K

E/W

0C to +60C lower byte,

last 128 addresses

Program Flash Memory

D122

VPR

VDD for Read

D123

TIW

Self-timed Write Cycle Time

D124

TRETD Characteristic Retention

D125

EHEFC High-Endurance Flash Cell

-40C to +85C (Note 1)

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Self-write and Block Erase.
2: Required only if single-supply programming is disabled.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 339

PIC16(L)F1508/9
29.6

Thermal Considerations

Standard Operating Conditions (unless otherwise stated)

Operating temperature -40C TA +125C
Param
No.
TH01

TH02

Sym.

Characteristic

Thermal Resistance Junction to Ambient

TH03

TJMAX

TH04

TH05

Thermal Resistance Junction to Case

Maximum Junction Temperature

Power Dissipation

PINTERNAL Internal Power Dissipation

Typ.

Units

Conditions

62.2

C/W

20-pin PDIP package

75.0

C/W

20-pin SOIC package

89.3

C/W

20-pin SSOP package

43.0

C/W

20-pin QFN 4X4mm package

27.5

C/W

20-pin PDIP package

23.1

C/W

20-pin SOIC package

31.1

C/W

20-pin SSOP package

5.3

C/W

20-pin QFN 4X4mm package

150

PD = PINTERNAL + PI/O

PINTERNAL = IDD x VDD(1)

TH06

PI/O

I/O Power Dissipation

PI/O = (IOL * VOL) + (IOH * (VDD - VOH))

TH07

PDER

Derated Power

PDER = PDMAX (TJ - TA)/JA(2)

Note 1: IDD is current to run the chip alone without driving any load on the output pins.
2: TA = Ambient Temperature
3: TJ = Junction Temperature

DS41609A-page 340

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
29.7

Timing Parameter Symbology

The timing parameter symbols have been created with

one of the following formats:
1. TppS2ppS
2. TppS
T
F
Frequency
Lowercase letters (pp) and their meanings:
pp
cc
CCP1
ck
CLKOUT
cs
CS
di
SDIx
do
SDO
dt
Data in
io
I/O PORT
mc
MCLR
Uppercase letters and their meanings:
S
F
Fall
H
High
I
Invalid (High-impedance)
L
Low

FIGURE 29-4:

Time

osc
rd
rw
sc
ss
t0
t1
wr

CLKIN
RD
RD or WR
SCKx
SS
T0CKI
T1CKI
WR

P
R
V
Z

Period
Rise
Valid
High-impedance

LOAD CONDITIONS
Load Condition

CL
VSS

Legend: CL = 50 pF for all pins

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 341

PIC16(L)F1508/9
29.8

AC Characteristics: PIC16(L)F1508/9-I/E

FIGURE 29-5:

CLOCK TIMING
Q4

CLKIN
OS12

OS02

OS11

OS03
CLKOUT
(CLKOUT Mode)

Note

See Table 29-3.

TABLE 29-1:

CLOCK OSCILLATOR TIMING REQUIREMENTS

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +125C
Param
No.
OS01

Sym.
FOSC

Characteristic
External CLKIN Frequency(1)

Min.

Typ

Max.

Units

Conditions

0.5

MHz

EC Oscillator mode (low)

MHz

EC Oscillator mode (medium)

EC Oscillator mode (high)

MHz

OS02

TOSC

External CLKIN Period(1)

31.25

EC mode

OS03

TCY

Instruction Cycle Time(1)

125

TCY = FOSC/4

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are based on
characterization data for that particular oscillator type under standard operating conditions with the device executing code.
Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at min values with an external clock applied to CLKIN pin. When an external
clock input is used, the max cycle time limit is DC (no clock) for all devices.

TABLE 29-2:

OSCILLATOR PARAMETERS

Standard Operating Conditions (unless otherwise stated)

Operating Temperature
-40C TA +125C
Param
No.

Sym.

Characteristic

Freq.
Tolerance

Min.

Typ

Max.

Units

Conditions

OS08

HFOSC

Internal Calibrated HFINTOSC

Frequency(1)

10%

16.0

MHz

0C TA +85C

OS09

LFOSC

Internal LFINTOSC Frequency

kHz

-40C TA +125C

OS10*

TIOSC ST HFINTOSC
Wake-up from Sleep Start-up Time

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as close to the device as
possible. 0.1 F and 0.01 F values in parallel are recommended.

DS41609A-page 342

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 29-6:

CLKOUT AND I/O TIMING

Cycle

Write

Fetch

Read

Execute

FOSC
OS12

OS11
OS20
OS21

CLKOUT
OS19

OS18

OS16

OS13

OS17

I/O pin
(Input)
OS14

OS15
I/O pin
(Output)

New Value

Old Value
OS18, OS19

TABLE 29-3:

CLKOUT AND I/O TIMING PARAMETERS

Standard Operating Conditions (unless otherwise stated)

Operating Temperature -40C TA +125C
Param
No.

OS11
OS12

Sym.

TosH2ckL

Characteristic

Min.

Typ

Max.

Units

Conditions

FOSC to CLKOUT (1)

VDD = 3.3-5.0V

(1)

VDD = 3.3-5.0V

TosH2ckH FOSC to CLKOUT

valid(1)

OS13

TckL2ioV

CLKOUT to Port out

OS14
OS15
OS16

TioV2ckH
TosH2ioV
TosH2ioI

OS17

TioV2osH

OS18* TioR

Port input valid before CLKOUT(1)

Fosc (Q1 cycle) to Port out valid
Fosc (Q2 cycle) to Port input invalid
(I/O in hold time)
Port input valid to Fosc(Q2 cycle)
(I/O in setup time)
Port output rise time(2)

OS19* TioF

Port output fall time(2)

TOSC + 200 ns

70*

ns
ns
ns

25
25

15
40
28
15

32
72
55
30

OS20* Tinp
OS21* Tioc

INT pin input high or low time

Interrupt-on-change new input level
time
* These parameters are characterized but not tested.
Data in Typ column is at 3.0V, 25C unless otherwise stated.
Note 1: Measurements are taken in EC mode where CLKOUT output is 4 x TOSC.

2011 Microchip Technology Inc.

Preliminary

VDD = 3.3-5.0V
VDD = 3.3-5.0V

VDD = 2.0V
VDD = 5.0V
VDD = 2.0V
VDD = 5.0V

ns
ns

DS41609A-page 343

PIC16(L)F1508/9
FIGURE 29-7:

RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP

TIMER TIMING

VDD
MCLR
30

Internal
POR
33

PWRT
Time-out
Internal Reset(1)
Watchdog Timer
Reset(1)

I/O pins

Note 1: Asserted low.

FIGURE 29-8:

BROWN-OUT RESET TIMING AND CHARACTERISTICS

VDD
VBOR and VHYST

VBOR

(Device in Brown-out Reset)

(Device not in Brown-out Reset)

Reset

33(1)

(due to BOR)

Note 1: 64 ms delay only if PWRTE bit in the Configuration Words is programmed to 0.

2 ms delay if PWRTE = 0 and VREGEN = 1.

DS41609A-page 344

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 29-4:

RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER

AND BROWN-OUT RESET PARAMETERS

Standard Operating Conditions (unless otherwise stated)

Operating Temperature -40C TA +125C
Param
No.

Sym.

Characteristic

Min.

Typ

Max.

Units

Conditions

2
5

s
s

VDD = 3.3-5V, -40C to +85C

VDD = 3.3-5V

VDD = 3.3V-5V,
1:16 Prescaler used

TMCL

MCLR Pulse Width (low)

TWDTLP Low-Power Watchdog Timer

Time-out Period

33*

TPWRT

Power-up Timer Period, PWRTE = 0

140

34*

TIOZ

I/O high-impedance from MCLR Low

or Watchdog Timer Reset

2.0

VBOR

Brown-out Reset Voltage

2.50

2.70

2.80

2.30
1.8

2.40
1.90

2.50
2.00

V
V

-40C to +85C

VDD VBOR

Brown-out Reset Hysteresis

36*

VHYST

37*

TBORDC Brown-out Reset DC Response

Time

BORV = 0, high trip point

BORV = 1, low trip point
(PIC16F1508/9)
(PIC16LF1508/9)

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: To ensure these voltage tolerances, VDD and VSS must be capacitively decoupled as close to the device as
possible. 0.1 F and 0.01 F values in parallel are recommended.

FIGURE 29-9:

TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS

T0CKI
40

41
42

T1CKI
45

46
47

TMR0 or
TMR1

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 345

PIC16(L)F1508/9
TABLE 29-5:

TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS

Standard Operating Conditions (unless otherwise stated)

Operating Temperature -40C TA +125C
Param
No.
40*

Sym.

Characteristic

TT0H

T0CKI High Pulse Width

Min.
No Prescaler

TT0L

T0CKI Low Pulse Width

No Prescaler

TT0P

T0CKI Period

45*

TT1H

T1CKI High Synchronous, No Prescaler

Time
Synchronous,
with Prescaler

0.5 TCY + 20

Greater of:
20 or TCY + 40
N

0.5 TCY + 20

Asynchronous
46*

TT1L

T1CKI Low
Time

Units

With Prescaler
42*

Max.

0.5 TCY + 20

With Prescaler
41*

Typ

Synchronous, No Prescaler

0.5 TCY + 20

Synchronous, with Prescaler

Asynchronous

Greater of:
30 or TCY + 40
N

47*

TT1P

49*

TCKEZTMR1 Delay from External Clock Edge to Timer

Increment

T1CKI Input Synchronous

Period
Asynchronous

2 TOSC

7 TOSC

Conditions

N = prescale value
(2, 4, ..., 256)

N = prescale value
(1, 2, 4, 8)

Timers in Sync
mode

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: For proper operation, the minimum value of the ADC positive voltage reference must be 1.8V or greater. When selecting
the FVR or the VREF+ pin as the source of the ADC positive voltage reference, be aware that the voltage must be 1.8V
or greater.

TABLE 29-6:

PIC16(L)F1508/9 A/D CONVERTER (ADC) CHARACTERISTICS:

Standard Operating Conditions (unless otherwise stated)

Operating temperature Tested at 25C
Param
Sym.
No.

Characteristic

Min.

Typ

Max.

Units

Conditions

AD01

Resolution

AD02

EIL

Integral Error

1.7

AD03

EDL

Differential Error

AD04

EOFF Offset Error

2.5

LSb VREF = 3.0V

AD05

EGN

2.0

LSb VREF = 3.0V

AD06

VREF Reference Voltage(3)

1.8

VDD

AD07

VAIN

Full-Scale Range

VSS

VREF

AD08

ZAIN

Recommended Impedance of
Analog Voltage Source

Note 1:
2:
3:
4:
5:

Gain Error

bit
LSb VREF = 3.0V
LSb No missing codes
VREF = 3.0V

VREF = (VREF+ minus VREF-) (NOTE 5)

Can go higher if external 0.01F capacitor is
present on input pin.

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Total Absolute Error includes integral, differential, offset and gain errors.
The A/D conversion result never decreases with an increase in the input voltage and has no missing codes.
ADC VREF is from external VREF+ pin, VDD pin, whichever is selected as reference input.
When ADC is off, it will not consume any current other than leakage current. The power-down current specification
includes any such leakage from the ADC module.
FVR voltage selected must be 2.048V or 4.096V.

DS41609A-page 346

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 29-7:

PIC16(L)F1508/9 A/D CONVERSION REQUIREMENTS

Standard Operating Conditions (unless otherwise stated)

Operating temperature
-40C TA +125C
Param
No.

Sym.

Characteristic

AD130* TAD

AD131

TCNV

AD132* TACQ

Min.

Typ

Max.

Units

Conditions

A/D Clock Period

1.0

9.0

TOSC-based

A/D Internal FRC Oscillator

Period

1.0

1.6

6.0

ADCS<1:0> = 11 (ADFRC mode)

Conversion Time (not including

Acquisition Time)(1)

TAD

Set GO/DONE bit to conversion

complete

Acquisition Time

5.0

These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: The ADRES register may be read on the following TCY cycle.

FIGURE 29-10:

PIC16(L)F1508/9 A/D CONVERSION TIMING (NORMAL MODE)

BSF ADCON0, GO
AD134

1 TCY

(TOSC/2(1))

AD131

AD130
A/D CLK
9

A/D Data

OLD_DATA

ADRES

0
NEW_DATA
1 TCY

ADIF
GO
Sample

DONE
AD132

Sampling Stopped

Note 1: If the A/D clock source is selected as FRC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 347

PIC16(L)F1508/9
FIGURE 29-11:

PIC16(L)F1508/9 A/D CONVERSION TIMING (SLEEP MODE)

BSF ADCON0, GO
AD134

(TOSC/2 + TCY(1))

1 TCY

AD131

AD130
A/D CLK
9

A/D Data

OLD_DATA

ADRES

0
NEW_DATA

ADIF

1 TCY

DONE

Sample

AD132

Sampling Stopped

Note 1: If the A/D clock source is selected as FRC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.

DS41609A-page 348

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 29-8:

COMPARATOR SPECIFICATIONS

Operating Conditions: 1.8V < VDD < 5.5V, -40C < TA < +125C (unless otherwise stated).
Param
No.

Sym.

Characteristics

Min.

Typ.

Max.

Units

Comments

CM01

VIOFF

Input Offset Voltage

7.5

CM02

VICM

Input Common Mode Voltage

VDD

CM04A

Response Time Rising Edge

400

800

High-Power mode
(Note 1)

CM04B

Response Time Falling Edge

200

400

High-Power mode
(Note 1)

Response Time Rising Edge

1200

Low-Power mode
(Note 1)

Response Time Falling Edge

550

Low-Power mode
(Note 1)

Comparator Mode Change to

Output Valid*

CM04C

TRESP

CM04D
TMC2OV

CM05

CHYSTER Comparator Hysteresis

CM06
*
Note 1:
2:

Note 2

These parameters are characterized but not tested.

Response time measured with one comparator input at VDD/2, while the other input transitions
from VSS to VDD.
Comparator Hysteresis is available when the CxHYS bit of the CMxCON0 register is enabled.

TABLE 29-9:

DIGITAL-TO-ANALOG CONVERTER (DAC) SPECIFICATIONS

Operating Conditions: 1.8V < VDD < 5.5V, -40C < TA < +125C (unless otherwise stated).
Param
No.

Sym.

Characteristics

Min.

Typ.

Max.

Units

DAC01*

CLSB

Step Size(2)

VDD/32

DAC02*

CACC

Absolute Accuracy

1/2

LSb

DAC03*

Unit Resistor Value (R)

CST

Time(1)

DAC04*

Settling

Comments

*
These parameters are characterized but not tested.
Legend: TBD = To Be Determined
Note 1: Settling time measured while DACR<4:0> transitions from 0000 to 1111.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 349

PIC16(L)F1508/9
FIGURE 29-12:

USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING

CK
US121

US121

DT
US122

US120
Note:

Refer to Figure 29-4 for load conditions.

TABLE 29-10: USART SYNCHRONOUS TRANSMISSION REQUIREMENTS

Standard Operating Conditions (unless otherwise stated)
Operating Temperature
-40C TA +125C
Param.
No.

Symbol

Characteristic

Min.

Max.

Units

US120 TCKH2DTV SYNC XMIT (Master and Slave)

Clock high to data-out valid

3.0-5.5V

1.8-5.5V

100

US121 TCKRF

Clock out rise time and fall time

(Master mode)

3.0-5.5V

1.8-5.5V

Data-out rise time and fall time

3.0-5.5V

1.8-5.5V

US122 TDTRF

FIGURE 29-13:

Conditions

USART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING

US125

DT
US126
Note: Refer to Figure 29-4 for load conditions.

TABLE 29-11: USART SYNCHRONOUS RECEIVE REQUIREMENTS

Standard Operating Conditions (unless otherwise stated)
Operating Temperature
-40C TA +125C
Param.
No.

Symbol

Characteristic

US125 TDTV2CKL SYNC RCV (Master and Slave)

Data-hold before CK (DT hold time)
US126 TCKL2DTL

DS41609A-page 350

Data-hold after CK (DT hold time)

Preliminary

Min.

Max.

Units

Conditions

2011 Microchip Technology Inc.

PIC16(L)F1508/9
FIGURE 29-14:

SPI MASTER MODE TIMING (CKE = 0, SMP = 0)

SS
SP70
SCK
(CKP = 0)
SP71

SP72
SP78

SP79

SP78

SCK
(CKP = 1)

SP80
bit 6 - - - - - -1

MSb

SDO

LSb

SP75, SP76
SDI

MSb In

bit 6 - - - -1

LSb In

SP74
SP73

Note: Refer to Figure 29-4 for load conditions.

FIGURE 29-15:

SPI MASTER MODE TIMING (CKE = 1, SMP = 1)

SS
SP81
SCK
(CKP = 0)
SP71

SP72
SP79

SP73
SCK
(CKP = 1)
SP80

SDO

MSb

SP78

bit 6 - - - - - -1

LSb

SP75, SP76
SDI

MSb In

bit 6 - - - -1

LSb In

SP74

Note: Refer to Figure 29-4 for load conditions.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 351

PIC16(L)F1508/9
FIGURE 29-16:

SPI SLAVE MODE TIMING (CKE = 0)

SS
SP70
SCK
(CKP = 0)

SP83
SP71

SP72
SP78

SP79

SP78

SCK
(CKP = 1)

SP80
MSb

SDO

LSb

bit 6 - - - - - -1

SP77

SP75, SP76
SDI

MSb In

bit 6 - - - -1

LSb In

SP74
SP73

Note: Refer to Figure 29-4 for load conditions.

FIGURE 29-17:
SS

SPI SLAVE MODE TIMING (CKE = 1)

SP82
SP70
SP83

SCK
(CKP = 0)
SP71

SP72

SCK
(CKP = 1)
SP80

SDO

MSb

bit 6 - - - - - -1

LSb
SP77

SP75, SP76
SDI

MSb In

bit 6 - - - -1

LSb In

SP74

Note: Refer to Figure 29-4 for load conditions.

DS41609A-page 352

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 29-12: SPI MODE REQUIREMENTS
Param
No.

Symbol

Characteristic

SP70* TSSL2SCH, SS to SCK or SCK input

TSSL2SCL

Min.

Typ

Max. Units Conditions

TCY

SP71* TSCH

SCK input high time (Slave mode)

TCY + 20

SP72* TSCL

SCK input low time (Slave mode)

TCY + 20

100

3.0-5.5V

1.8-5.5V

SP73* TDIV2SCH, Setup time of SDI data input to SCK edge

TDIV2SCL
SP74* TSCH2DIL,
TSCL2DIL

Hold time of SDI data input to SCK edge

SP75* TDOR

SDO data output rise time

SP76* TDOF

SDO data output fall time

SP77* TSSH2DOZ

SS to SDO output high-impedance

SP78* TSCR

SCK output rise time

(Master mode)

3.0-5.5V

1.8-5.5V

SP79* TSCF

SCK output fall time (Master mode)

3.0-5.5V

1.8-5.5V

145

Tcy

1.5TCY + 40

SP80* TSCH2DOV, SDO data output valid after

TSCL2DOV SCK edge

SP81* TDOV2SCH, SDO data output setup to SCK edge

TDOV2SCL
SP82* TSSL2DOV

SDO data output valid after SS edge

SP83* TSCH2SSH, SS after SCK edge

TSCL2SSH

* These parameters are characterized but not tested.

Data in Typ column is at 3.0V, 25C unless otherwise stated. These parameters are for design guidance
only and are not tested.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 353

PIC16(L)F1508/9
FIGURE 29-18:

I2C BUS START/STOP BITS TIMING

SCL
SP93

SP91
SP90

SP92

SDA

Stop
Condition

Start
Condition

Note: Refer to Figure 29-4 for load conditions.

TABLE 29-13: I2C BUS START/STOP BITS REQUIREMENTS

Param
No.

Symbol

SP90*

TSU:STA

SP91*

THD:STA

SP92*

TSU:STO

SP93

Characteristic

Typ

Max. Units

Start condition

100 kHz mode

4700

Setup time

400 kHz mode

600

Start condition

100 kHz mode

4000

Hold time

400 kHz mode

600

Stop condition

100 kHz mode

4700

Setup time

400 kHz mode

600

100 kHz mode

4000

400 kHz mode

600

THD:STO Stop condition

Hold time
*

Min.

Conditions

Only relevant for Repeated

Start condition

After this period, the first

clock pulse is generated

ns
ns

These parameters are characterized but not tested.

FIGURE 29-19:

I2C BUS DATA TIMING

SP103

SCL

SP100

SP90

SP102

SP101

SP106

SP107

SP91
SDA
In

SP92
SP110

SP109

SDA
Out

Note: Refer to Figure 29-4 for load conditions.

DS41609A-page 354

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
TABLE 29-14: I2C BUS DATA REQUIREMENTS
Param.
No.

Symbol

SP100* THIGH

Characteristic

Clock high time

Min.

Max.

Units

100 kHz mode

4.0

Device must operate at a

minimum of 1.5 MHz

400 kHz mode

0.6

Device must operate at a

minimum of 10 MHz

1.5TCY

100 kHz mode

4.7

Device must operate at a

minimum of 1.5 MHz

400 kHz mode

1.3

Device must operate at a

minimum of 10 MHz

SSP module
SP101* TLOW

Clock low time

1.5TCY

SDA and SCL rise

time

100 kHz mode

1000

400 kHz mode

20 + 0.1CB

300

SDA and SCL fall

time

100 kHz mode

250

400 kHz mode

20 + 0.1CB

250

SSP module
SP102* TR

SP103* TF

SP106* THD:DAT
SP107* TSU:DAT
SP109* TAA
SP110*

SP111
*
Note 1:
2:

TBUF

Data input hold time 100 kHz mode

400 kHz mode

0.9

Data input setup

time
Output valid from
clock
Bus free time

Conditions

100 kHz mode

250

400 kHz mode

100

100 kHz mode

3500

400 kHz mode

100 kHz mode

4.7

400 kHz mode

1.3

400

Bus capacitive loading

CB is specified to be from
10-400 pF
CB is specified to be from
10-400 pF

(Note 2)
(Note 1)

Time the bus must be free

before a new transmission
can start

These parameters are characterized but not tested.

As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region
(min. 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
A Fast mode (400 kHz) I2C bus device can be used in a Standard mode (100 kHz) I2C bus system, but
the requirement TSU:DAT 250 ns must then be met. This will automatically be the case if the device does
not stretch the low period of the SCL signal. If such a device does stretch the low period of the SCL signal,
it must output the next data bit to the SDA line TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to
the Standard mode I2C bus specification), before the SCL line is released.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 355

PIC16(L)F1508/9
NOTES:

DS41609A-page 356

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
30.0

DC AND AC
CHARACTERISTICS GRAPHS
AND CHARTS

Graphs and charts are not available at this time.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 357

PIC16(L)F1508/9
NOTES:

DS41609A-page 358

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
31.0

DEVELOPMENT SUPPORT

31.1

The PIC microcontrollers and dsPIC digital signal

controllers are supported with a full range of software
and hardware development tools:
Integrated Development Environment
- MPLAB IDE Software
Compilers/Assemblers/Linkers
- MPLAB C Compiler for Various Device
Families
- HI-TECH C for Various Device Families
- MPASMTM Assembler
- MPLINKTM Object Linker/
MPLIBTM Object Librarian
- MPLAB Assembler/Linker/Librarian for
Various Device Families
Simulators
- MPLAB SIM Software Simulator
Emulators
- MPLAB REAL ICE In-Circuit Emulator
In-Circuit Debuggers
- MPLAB ICD 3
- PICkit 3 Debug Express
Device Programmers
- PICkit 2 Programmer
- MPLAB PM3 Device Programmer
Low-Cost Demonstration/Development Boards,
Evaluation Kits, and Starter Kits

MPLAB Integrated Development

Environment Software

The MPLAB IDE software brings an ease of software

development previously unseen in the 8/16/32-bit
microcontroller market. The MPLAB IDE is a Windows
operating system-based application that contains:
A single graphical interface to all debugging tools
- Simulator
- Programmer (sold separately)
- In-Circuit Emulator (sold separately)
- In-Circuit Debugger (sold separately)
A full-featured editor with color-coded context
A multiple project manager
Customizable data windows with direct edit of
contents
High-level source code debugging
Mouse over variable inspection
Drag and drop variables from source to watch
windows
Extensive on-line help
Integration of select third party tools, such as
IAR C Compilers
The MPLAB IDE allows you to:
Edit your source files (either C or assembly)
One-touch compile or assemble, and download to
emulator and simulator tools (automatically
updates all project information)
Debug using:
- Source files (C or assembly)
- Mixed C and assembly
- Machine code
MPLAB IDE supports multiple debugging tools in a
single development paradigm, from the cost-effective
simulators, through low-cost in-circuit debuggers, to
full-featured emulators. This eliminates the learning
curve when upgrading to tools with increased flexibility
and power.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 359

PIC16(L)F1508/9
31.2

MPLAB C Compilers for Various

Device Families

The MPLAB C Compiler code development systems

are complete ANSI C compilers for Microchips PIC18,
PIC24 and PIC32 families of microcontrollers and the
dsPIC30 and dsPIC33 families of digital signal controllers. These compilers provide powerful integration
capabilities, superior code optimization and ease of
use.
For easy source level debugging, the compilers provide
symbol information that is optimized to the MPLAB IDE
debugger.

31.3

HI-TECH C for Various Device

Families

For easy source level debugging, the compilers provide

symbol information that is optimized to the MPLAB IDE
debugger.
The compilers include a macro assembler, linker, preprocessor, and one-step driver, and can run on multiple
platforms.

MPASM Assembler

The MPASM Assembler is a full-featured, universal

macro assembler for PIC10/12/16/18 MCUs.
The MPASM Assembler generates relocatable object
files for the MPLINK Object Linker, Intel standard HEX
files, MAP files to detail memory usage and symbol
reference, absolute LST files that contain source lines
and generated machine code and COFF files for
debugging.
The MPASM Assembler features include:

MPLINK Object Linker/

MPLIB Object Librarian

The MPLINK Object Linker combines relocatable

objects created by the MPASM Assembler and the
MPLAB C18 C Compiler. It can link relocatable objects
from precompiled libraries, using directives from a
linker script.
The MPLIB Object Librarian manages the creation and
modification of library files of precompiled code. When
a routine from a library is called from a source file, only
the modules that contain that routine will be linked in
with the application. This allows large libraries to be
used efficiently in many different applications.
The object linker/library features include:

The HI-TECH C Compiler code development systems

are complete ANSI C compilers for Microchips PIC
family of microcontrollers and the dsPIC family of digital
signal controllers. These compilers provide powerful
integration capabilities, omniscient code generation
and ease of use.

31.4

31.5

Efficient linking of single libraries instead of many

smaller files
Enhanced code maintainability by grouping
related modules together
Flexible creation of libraries with easy module
listing, replacement, deletion and extraction

31.6

MPLAB Assembler, Linker and

Librarian for Various Device
Families

MPLAB Assembler produces relocatable machine

code from symbolic assembly language for PIC24,
PIC32 and dsPIC devices. MPLAB C Compiler uses
the assembler to produce its object file. The assembler
generates relocatable object files that can then be
archived or linked with other relocatable object files and
archives to create an executable file. Notable features
of the assembler include:

Support for the entire device instruction set

Support for fixed-point and floating-point data
Command line interface
Rich directive set
Flexible macro language
MPLAB IDE compatibility

Integration into MPLAB IDE projects

User-defined macros to streamline
assembly code
Conditional assembly for multi-purpose
source files
Directives that allow complete control over the
assembly process

DS41609A-page 360

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
31.7

MPLAB SIM Software Simulator

31.9

The MPLAB SIM Software Simulator allows code

development in a PC-hosted environment by simulating the PIC MCUs and dsPIC DSCs on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a comprehensive stimulus controller. Registers can be
logged to files for further run-time analysis. The trace
buffer and logic analyzer display extend the power of
the simulator to record and track program execution,
actions on I/O, most peripherals and internal registers.
The MPLAB SIM Software Simulator fully supports
symbolic debugging using the MPLAB C Compilers,
and the MPASM and MPLAB Assemblers. The software simulator offers the flexibility to develop and
debug code outside of the hardware laboratory environment, making it an excellent, economical software
development tool.

31.8

MPLAB REAL ICE In-Circuit

Emulator System

MPLAB REAL ICE In-Circuit Emulator System is

Microchips next generation high-speed emulator for
Microchip Flash DSC and MCU devices. It debugs and
programs PIC Flash MCUs and dsPIC Flash DSCs
with the easy-to-use, powerful graphical user interface of
the MPLAB Integrated Development Environment (IDE),
included with each kit.
The emulator is connected to the design engineers PC
using a high-speed USB 2.0 interface and is connected
to the target with either a connector compatible with incircuit debugger systems (RJ11) or with the new highspeed, noise tolerant, Low-Voltage Differential Signal
(LVDS) interconnection (CAT5).
The emulator is field upgradable through future firmware
downloads in MPLAB IDE. In upcoming releases of
MPLAB IDE, new devices will be supported, and new
features will be added. MPLAB REAL ICE offers
significant advantages over competitive emulators
including low-cost, full-speed emulation, run-time
variable watches, trace analysis, complex breakpoints, a
ruggedized probe interface and long (up to three meters)
interconnection cables.

2011 Microchip Technology Inc.

MPLAB ICD 3 In-Circuit Debugger

System

MPLAB ICD 3 In-Circuit Debugger System is Microchip's most cost effective high-speed hardware
debugger/programmer for Microchip Flash Digital Signal Controller (DSC) and microcontroller (MCU)
devices. It debugs and programs PIC Flash microcontrollers and dsPIC DSCs with the powerful, yet easyto-use graphical user interface of MPLAB Integrated
Development Environment (IDE).
The MPLAB ICD 3 In-Circuit Debugger probe is connected to the design engineer's PC using a high-speed
USB 2.0 interface and is connected to the target with a
connector compatible with the MPLAB ICD 2 or MPLAB
REAL ICE systems (RJ-11). MPLAB ICD 3 supports all
MPLAB ICD 2 headers.

31.10 PICkit 3 In-Circuit Debugger/

Programmer and
PICkit 3 Debug Express
The MPLAB PICkit 3 allows debugging and programming of PIC and dsPIC Flash microcontrollers at a
most affordable price point using the powerful graphical
user interface of the MPLAB Integrated Development
Environment (IDE). The MPLAB PICkit 3 is connected
to the design engineer's PC using a full speed USB
interface and can be connected to the target via an
Microchip debug (RJ-11) connector (compatible with
MPLAB ICD 3 and MPLAB REAL ICE). The connector
uses two device I/O pins and the reset line to implement in-circuit debugging and In-Circuit Serial Programming.
The PICkit 3 Debug Express include the PICkit 3, demo
board and microcontroller, hookup cables and CDROM
with users guide, lessons, tutorial, compiler and
MPLAB IDE software.

Preliminary

DS41609A-page 361

PIC16(L)F1508/9
31.11 PICkit 2 Development
Programmer/Debugger and
PICkit 2 Debug Express

31.13 Demonstration/Development
Boards, Evaluation Kits, and
Starter Kits

The PICkit 2 Development Programmer/Debugger is

a low-cost development tool with an easy to use interface for programming and debugging Microchips Flash
families of microcontrollers. The full featured
Windows programming interface supports baseline
(PIC10F,
PIC12F5xx,
PIC16F5xx),
midrange
(PIC12F6xx, PIC16F), PIC18F, PIC24, dsPIC30,
dsPIC33, and PIC32 families of 8-bit, 16-bit, and 32-bit
microcontrollers, and many Microchip Serial EEPROM
products. With Microchips powerful MPLAB Integrated
Development Environment (IDE) the PICkit 2
enables in-circuit debugging on most PIC microcontrollers. In-Circuit-Debugging runs, halts and single
steps the program while the PIC microcontroller is
embedded in the application. When halted at a breakpoint, the file registers can be examined and modified.

A wide variety of demonstration, development and

evaluation boards for various PIC MCUs and dsPIC
DSCs allows quick application development on fully functional systems. Most boards include prototyping areas for
adding custom circuitry and provide application firmware
and source code for examination and modification.

The PICkit 2 Debug Express include the PICkit 2, demo

board and microcontroller, hookup cables and CDROM
with users guide, lessons, tutorial, compiler and
MPLAB IDE software.

31.12 MPLAB PM3 Device Programmer

The MPLAB PM3 Device Programmer is a universal,
CE compliant device programmer with programmable
voltage verification at VDDMIN and VDDMAX for
maximum reliability. It features a large LCD display
(128 x 64) for menus and error messages and a modular, detachable socket assembly to support various
package types. The ICSP cable assembly is included
as a standard item. In Stand-Alone mode, the MPLAB
PM3 Device Programmer can read, verify and program
PIC devices without a PC connection. It can also set
code protection in this mode. The MPLAB PM3
connects to the host PC via an RS-232 or USB cable.
The MPLAB PM3 has high-speed communications and
optimized algorithms for quick programming of large
memory devices and incorporates an MMC card for file
storage and data applications.

DS41609A-page 362

The boards support a variety of features, including LEDs,

temperature sensors, switches, speakers, RS-232
interfaces, LCD displays, potentiometers and additional
EEPROM memory.
The demonstration and development boards can be
used in teaching environments, for prototyping custom
circuits and for learning about various microcontroller
applications.
In addition to the PICDEM and dsPICDEM demonstration/development board series of circuits, Microchip
has a line of evaluation kits and demonstration software
for analog filter design, KEELOQ security ICs, CAN,
IrDA, PowerSmart battery management, SEEVAL
evaluation system, Sigma-Delta ADC, flow rate
sensing, plus many more.
Also available are starter kits that contain everything
needed to experience the specified device. This usually
includes a single application and debug capability, all
on one board.
Check the Microchip web page (www.microchip.com)
for the complete list of demonstration, development
and evaluation kits.

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
32.0

PACKAGING INFORMATION

32.1

Package Marking Information

20-Lead PDIP (300 mil)

Example

PIC16F1508
-E/P e3
1120123

XXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXX
YYWWNNN

20-Lead SOIC (7.50 mm)

Example

PIC16F1508
-E/SO e3
1120123

Legend: XX...X
Y
YY
WW
NNN

*
Note:

Customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week 01)
Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.

In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.

Standard PICmicro device marking consists of Microchip part number, year code, week code and
traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check
with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP
price.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 363

PIC16(L)F1508/9
32.2

Package Marking Information

20-Lead SSOP (5.30 mm)

Example

PIC16F1508
-E/SS e3
1120123

20-Lead QFN (4x4x0.9 mm)

Example

PIN 1

DS41609A-page 364

PIN 1

Preliminary

PIC16
F1508
-E/ML e3
120123

2011 Microchip Technology Inc.

PIC16(L)F1508/9
32.3

Package Details

The following sections give the technical details of the packages.

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2011 Microchip Technology Inc.

Preliminary

DS41609A-page 365

PIC16(L)F1508/9

Note:

For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging

DS41609A-page 366

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9

Note:

For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 367

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DS41609A-page 368

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9

Note:

For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 369

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Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9

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2011 Microchip Technology Inc.

Preliminary

DS41609A-page 371

PIC16(L)F1508/9
NOTES:

DS41609A-page 372

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
APPENDIX A:

DATA SHEET
REVISION HISTORY

Revision A
Original release (10/2011).

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 373

PIC16(L)F1508/9
NOTES:

DS41609A-page 374

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
INDEX
A
A/D
Specifications.................................................... 346, 347
Absolute Maximum Ratings .............................................. 329
AC Characteristics
Industrial and Extended ............................................ 342
Load Conditions ........................................................ 341
ACKSTAT ......................................................................... 218
ACKSTAT Status Flag ...................................................... 218
ADC .................................................................................. 135
Acquisition Requirements ......................................... 146
Associated registers.................................................. 148
Block Diagram........................................................... 135
Calculating Acquisition Time..................................... 146
Channel Selection..................................................... 136
Configuration............................................................. 136
Configuring Interrupt ................................................. 140
Conversion Clock...................................................... 136
Conversion Procedure .............................................. 140
Internal Sampling Switch (RSS) Impedance.............. 146
Interrupts................................................................... 138
Operation .................................................................. 139
Operation During Sleep ............................................ 139
Port Configuration ..................................................... 136
Reference Voltage (VREF)......................................... 136
Source Impedance.................................................... 146
Starting an A/D Conversion ...................................... 138
ADCON0 Register....................................................... 29, 141
ADCON1 Register....................................................... 29, 142
ADCON2 Register............................................................. 143
ADDFSR ........................................................................... 319
ADDWFC .......................................................................... 319
ADRESH Register............................................................... 29
ADRESH Register (ADFM = 0) ......................................... 144
ADRESH Register (ADFM = 1) ......................................... 145
ADRESL Register (ADFM = 0).......................................... 144
ADRESL Register (ADFM = 1).......................................... 145
Alternate Pin Function....................................................... 112
Analog-to-Digital Converter. See ADC
ANSELA Register ............................................................. 115
ANSELB Register ............................................................. 119
ANSELC Register ............................................................. 123
APFCON Register............................................................. 112
Assembler
MPASM Assembler................................................... 360
Automatic Context Saving................................................... 77

B
Bank 10 ............................................................................... 32
Bank 11 ............................................................................... 32
Bank 12 ............................................................................... 32
Bank 13 ............................................................................... 32
Bank 2 ................................................................................. 30
Bank 3 ................................................................................. 30
Bank 30 ............................................................................... 33
Bank 4 ................................................................................. 31
Bank 5 ................................................................................. 31
Bank 6 ................................................................................. 31
Bank 7 ................................................................................. 31
Bank 8 ................................................................................. 31
Bank 9 ................................................................................. 31
BAUDCON Register.......................................................... 248
BF ............................................................................. 218, 220

2011 Microchip Technology Inc.

BF Status Flag .......................................................... 218, 220

Block Diagrams
ADC .......................................................................... 135
ADC Transfer Function............................................. 147
Analog Input Model........................................... 147, 158
Block Diagrams
PIC16(L)1508/9 .................................................... 5
Clock Source .............................................................. 50
Comparator............................................................... 154
Crystal Operation.................................................. 52, 53
Digital-to-Analog Converter (DAC) ........................... 150
EUSART Receive ..................................................... 238
EUSART Transmit .................................................... 237
External RC Mode ...................................................... 53
Fail-Safe Clock Monitor (FSCM)................................. 60
Generic I/O Port........................................................ 111
Interrupt Logic............................................................. 73
NCO.......................................................................... 288
On-Chip Reset Circuit................................................. 65
PIC16(L)F1508/9 ........................................................ 10
PWM......................................................................... 265
Resonator Operation .................................................. 52
Timer0 ...................................................................... 163
Timer1 ...................................................................... 167
Timer1 Gate.............................................. 172, 173, 174
Timer2 ...................................................................... 179
Voltage Reference.................................................... 131
Voltage Reference Output Buffer Example .............. 150
BORCON Register.............................................................. 67
BRA .................................................................................. 320
Break Character (12-bit) Transmit and Receive ............... 257
Brown-out Reset (BOR)...................................................... 67
Specifications ........................................................... 345
Timing and Characteristics ....................................... 344

C
C Compilers
MPLAB C18.............................................................. 360
CALL................................................................................. 321
CALLW ............................................................................. 321
CLCDATA Register........................................................... 285
CLCxCON Register .......................................................... 277
CLCxGLS0 Register ......................................................... 281
CLCxGLS1 Register ......................................................... 282
CLCxGLS2 Register ......................................................... 283
CLCxGLS3 Register ......................................................... 284
CLCxPOL Register ........................................................... 278
CLCxSEL0 Register.......................................................... 279
Clock Accuracy with Asynchronous Operation ................. 246
Clock Sources
External Modes........................................................... 51
EC ...................................................................... 51
HS ...................................................................... 51
LP ....................................................................... 51
OST .................................................................... 52
RC ...................................................................... 53
XT ....................................................................... 51
Internal Modes............................................................ 54
HFINTOSC ......................................................... 54
Internal Oscillator Clock Switch Timing .............. 55
LFINTOSC.......................................................... 54
Clock Switching .................................................................. 57
CMOUT Register .............................................................. 160
CMxCON0 Register .......................................................... 159

Preliminary

DS41609A-page 375

PIC16(L)F1508/9
CMxCON1 Register .......................................................... 160
Code Examples
A/D Conversion ......................................................... 140
Initializing PORTA ..................................................... 113
Writing to Flash Program Memory ............................ 104
Comparator
Associated Registers ................................................ 161
Operation .................................................................. 153
Comparator Module .......................................................... 153
Cx Output State Versus Input Conditions ................. 155
Comparator Specifications ................................................ 349
Comparators
C2OUT as T1 Gate ................................................... 169
Complementary Waveform Generator (CWG) .......... 297, 298
CONFIG1 Register.............................................................. 44
CONFIG2 Register.............................................................. 45
Core Function Register ....................................................... 28
Customer Change Notification Service ............................. 381
Customer Notification Service........................................... 381
Customer Support ............................................................. 381
CWG
Auto-shutdown Control ............................................. 304
Clock Source............................................................. 300
Output Control........................................................... 300
Selectable Input Sources .......................................... 300
CWGxCON0 Register ....................................................... 307
CWGxCON1 Register ....................................................... 308
CWGxCON2 Register ....................................................... 309
CWGxDBF Register .......................................................... 310
CWGxDBR Register.......................................................... 310

D
DACCON0 (Digital-to-Analog Converter Control 0)
Register..................................................................... 152
DACCON1 (Digital-to-Analog Converter Control 1)
Register..................................................................... 152
Data Memory....................................................................... 20
DC and AC Characteristics ............................................... 357
DC Characteristics
Extended and Industrial ............................................ 338
Industrial and Extended ............................................ 331
Development Support ....................................................... 359
Device Configuration........................................................... 43
Code Protection .......................................................... 46
Configuration Word ..................................................... 43
User ID .................................................................. 46, 47
Device ID Register .............................................................. 47
Device Overview ............................................................. 9, 91
Digital-to-Analog Converter (DAC).................................... 149
Associated Registers ................................................ 152
Effects of a Reset...................................................... 150
Specifications ............................................................ 349

E
Effects of Reset
PWM mode ............................................................... 267
Electrical Specifications .................................................... 329
Enhanced Mid-Range CPU................................................. 15
Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART)............................... 237
Errata .................................................................................... 8
EUSART............................................................................ 237
Associated Registers
Baud Rate Generator........................................ 250
Asynchronous Mode ................................................. 239
12-bit Break Transmit and Receive................... 257

DS41609A-page 376

Associated Registers
Receive .................................................... 245
Transmit.................................................... 241
Auto-Wake-up on Break ................................... 255
Baud Rate Generator (BRG) ............................ 249
Clock Accuracy................................................. 246
Receiver ........................................................... 242
Setting up 9-bit Mode with Address Detect ...... 244
Transmitter ....................................................... 239
Baud Rate Generator (BRG)
Auto Baud Rate Detect..................................... 254
Baud Rate Error, Calculating............................ 249
Baud Rates, Asynchronous Modes .................. 251
Formulas........................................................... 250
High Baud Rate Select (BRGH Bit) .................. 249
Synchronous Master Mode............................... 258, 262
Associated Registers
Receive .................................................... 261
Transmit.................................................... 259
Reception ......................................................... 260
Transmission .................................................... 258
Synchronous Slave Mode
Associated Registers
Receive .................................................... 263
Transmit.................................................... 262
Reception ......................................................... 263
Transmission .................................................... 262
Extended Instruction Set
ADDFSR ................................................................... 319

F
Fail-Safe Clock Monitor ...................................................... 60
Fail-Safe Condition Clearing....................................... 60
Fail-Safe Detection ..................................................... 60
Fail-Safe Operation..................................................... 60
Reset or Wake-up from Sleep .................................... 60
Firmware Instructions ....................................................... 315
Fixed Voltage Reference (FVR)........................................ 131
Associated Registers ................................................ 132
Flash Program Memory ...................................................... 95
Associated Registers ................................................ 110
Configuration Word w/ Flash Program Memory........ 110
Erasing ....................................................................... 99
Modifying .................................................................. 105
Write Verify ............................................................... 107
Writing ...................................................................... 101
FSR Register ...................................................................... 28
FVRCON (Fixed Voltage Reference Control) Register..... 132

I
I2C Mode (MSSPx)
Acknowledge Sequence Timing ............................... 222
Bus Collision
During a Repeated Start Condition................... 227
During a Stop Condition ................................... 228
Effects of a Reset ..................................................... 223
I2C Clock Rate w/BRG.............................................. 230
Master Mode
Operation.......................................................... 214
Reception ......................................................... 220
Start Condition Timing .............................. 216, 217
Transmission .................................................... 218
Multi-Master Communication, Bus Collision and
Arbitration ......................................................... 223
Multi-Master Mode .................................................... 223
Read/Write Bit Information (R/W Bit) ........................ 198

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
Slave Mode
Transmission .................................................... 204
Sleep Operation ........................................................ 223
Stop Condition Timing............................................... 222
INDF Register ..................................................................... 28
Indirect Addressing ............................................................. 38
Instruction Format ............................................................. 316
Instruction Set ................................................................... 315
ADDLW ..................................................................... 319
ADDWF..................................................................... 319
ADDWFC .................................................................. 319
ANDLW ..................................................................... 319
ANDWF..................................................................... 319
BRA........................................................................... 320
CALL ......................................................................... 321
CALLW...................................................................... 321
LSLF ......................................................................... 323
LSRF......................................................................... 323
MOVF........................................................................ 323
MOVIW ..................................................................... 324
MOVLB ..................................................................... 324
MOVWI ..................................................................... 325
OPTION .................................................................... 325
RESET ...................................................................... 325
SUBWFB................................................................... 327
TRIS.......................................................................... 328
BCF........................................................................... 320
BSF ........................................................................... 320
BTFSC ...................................................................... 320
BTFSS ...................................................................... 320
CALL ......................................................................... 321
CLRF......................................................................... 321
CLRW ....................................................................... 321
CLRWDT................................................................... 321
COMF ....................................................................... 321
DECF ........................................................................ 321
DECFSZ.................................................................... 322
GOTO ....................................................................... 322
INCF.......................................................................... 322
INCFSZ ..................................................................... 322
IORLW ...................................................................... 322
IORWF ...................................................................... 322
MOVLW .................................................................... 324
MOVWF .................................................................... 324
NOP .......................................................................... 325
RETFIE ..................................................................... 326
RETLW ..................................................................... 326
RETURN ................................................................... 326
RLF ........................................................................... 326
RRF........................................................................... 327
SLEEP ...................................................................... 327
SUBLW ..................................................................... 327
SUBWF ..................................................................... 327
SWAPF ..................................................................... 328
XORLW..................................................................... 328
XORWF..................................................................... 328
INTCON Register ................................................................ 78
Internal Oscillator Block
INTOSC
Specifications.................................................... 342
Internal Sampling Switch (RSS) Impedance ...................... 146
Internet Address................................................................ 381
Interrupt-On-Change ......................................................... 125
Associated Registers ................................................ 129
Interrupts ............................................................................. 73

2011 Microchip Technology Inc.

ADC .......................................................................... 140

Associated registers w/ Interrupts .............................. 85
Configuration Word w/ Clock Sources........................ 63
TMR1........................................................................ 171
INTOSC Specifications ..................................................... 342
IOCAF Register ................................................................ 127
IOCAN Register ................................................................ 127
IOCAP Register ................................................................ 127
IOCBF Register ................................................................ 128
IOCBN Register ................................................................ 128
IOCBP Register ................................................................ 128

L
LATA Register .......................................................... 115, 122
LATB Register .................................................................. 119
Load Conditions................................................................ 341
LSLF ................................................................................. 323
LSRF ................................................................................ 323

M
Master Synchronous Serial Port. See MSSPx
MCLR ................................................................................. 68
Internal........................................................................ 68
Memory Organization ......................................................... 17
Data ............................................................................ 20
Program...................................................................... 17
Microchip Internet Web Site.............................................. 381
MOVIW ............................................................................. 324
MOVLB ............................................................................. 324
MOVWI ............................................................................. 325
MPLAB ASM30 Assembler, Linker, Librarian ................... 360
MPLAB Integrated Development Environment Software.. 359
MPLAB PM3 Device Programmer .................................... 362
MPLAB REAL ICE In-Circuit Emulator System ................ 361
MPLINK Object Linker/MPLIB Object Librarian ................ 360
MSSPx.............................................................................. 183
SPI Mode.................................................................. 186
SSPxBUF Register ................................................... 189
SSPxSR Register ..................................................... 189

N
NCO
Associated registers ................................................. 296
NCOxACCH Register ....................................................... 294
NCOxACCL Register ........................................................ 294
NCOxACCU Register ....................................................... 294
NCOxCLK Register........................................................... 293
NCOxCON Register.......................................................... 293
NCOxINCH Register......................................................... 295
NCOxINCL Register ......................................................... 295
Numerically Controlled Oscillator (NCO) .......................... 287

O
OPCODE Field Descriptions............................................. 315
OPTION ............................................................................ 325
OPTION Register.............................................................. 165
OSCCON Register.............................................................. 62
Oscillator
Associated Registers.................................................. 63
Associated registers ................................................. 311
Oscillator Module ................................................................ 49
ECH ............................................................................ 49
ECL............................................................................. 49
ECM............................................................................ 49
HS............................................................................... 49
INTOSC ...................................................................... 49

Preliminary

DS41609A-page 377

PIC16(L)F1508/9
LP................................................................................ 49
RC ............................................................................... 49
XT ............................................................................... 49
Oscillator Parameters........................................................ 342
Oscillator Specifications .................................................... 342
Oscillator Start-up Timer (OST)
Specifications ............................................................ 345
Oscillator Switching
Fail-Safe Clock Monitor............................................... 60
Two-Speed Clock Start-up .......................................... 58
OSCSTAT Register............................................................. 63

P
Packaging ......................................................................... 363
Marking ............................................................. 363, 364
PDIP Details.............................................................. 365
PCL and PCLATH ............................................................... 16
PCL Register....................................................................... 28
PCLATH Register................................................................ 28
PCON Register ............................................................. 29, 71
PIE1 Register ................................................................ 29, 79
PIE2 Register ................................................................ 29, 80
PIE3 Register ................................................................ 29, 81
Pinout Descriptions
PIC16(L)F1508/9 ........................................................ 11
PIR1 Register................................................................ 29, 82
PIR2 Register................................................................ 29, 83
PIR3 Register................................................................ 29, 84
PMADR Registers ............................................................... 95
PMADRH Registers ............................................................ 95
PMADRL Register............................................................. 108
PMADRL Registers ............................................................. 95
PMCON1 Register ...................................................... 95, 109
PMCON2 Register ...................................................... 95, 110
PMDATH Register............................................................. 108
PMDATL Register ............................................................. 108
PMDRH Register............................................................... 108
PORTA.............................................................................. 113
ANSELA Register ..................................................... 113
Associated Registers ................................................ 116
LATA Register............................................................. 30
PORTA Register ......................................................... 29
Specifications ............................................................ 343
PORTA Register ............................................................... 114
PORTB.............................................................................. 117
ANSELB Register ..................................................... 117
Associated Registers ................................................ 120
LATB Register............................................................. 30
PORTB Register ......................................................... 29
PORTB Register ............................................................... 118
PORTC
ANSELC Register ..................................................... 121
Associated Registers ................................................ 123
LATC Register ............................................................ 30
Pin Descriptions and Diagrams................................. 121
PORTC Register ......................................................... 29
PORTC Register ............................................................... 122
Power-Down Mode (Sleep) ................................................. 87
Associated Registers .................................................. 90
Power-on Reset .................................................................. 66
Power-up Time-out Sequence ............................................ 68
Power-up Timer (PWRT)..................................................... 66
Specifications ............................................................ 345
PR2 Register....................................................................... 29
Program Memory ................................................................ 17
Map and Stack (PIC16(L)F1508 ................................. 18

DS41609A-page 378

Map and Stack (PIC16(L)F1509 ................................. 18

Programming, Device Instructions .................................... 315
Pulse Width Modulation (PWM)........................................ 265
Associated registers w/ PWM ................................... 270
PWM Mode
Duty Cycle ........................................................ 266
Effects of Reset ................................................ 267
Example PWM Frequencies and
Resolutions, 20 MHZ ................................ 267
Example PWM Frequencies and
Resolutions, 8 MHz .................................. 267
Operation in Sleep Mode.................................. 267
Setup for Operation using PWMx pins ............. 268
System Clock Frequency Changes .................. 267
PWM Period.............................................................. 266
Setup for PWM Operation using PWMx Pins ........... 268
PWMxCON Register ......................................................... 269
PWMxDCH Register ......................................................... 270
PWMxDCL Register.......................................................... 270

R
RCREG............................................................................. 244
RCREG Register ................................................................ 30
RCSTA Register ......................................................... 30, 247
Reader Response............................................................. 382
Read-Modify-Write Operations ......................................... 315
Registers
ADCON0 (ADC Control 0) ........................................ 141
ADCON1 (ADC Control 1) ........................................ 142
ADCON2 (ADC Control 2) ........................................ 143
ADRESH (ADC Result High) with ADFM = 0) .......... 144
ADRESH (ADC Result High) with ADFM = 1) .......... 145
ADRESL (ADC Result Low) with ADFM = 0)............ 144
ADRESL (ADC Result Low) with ADFM = 1)............ 145
ANSELA (PORTA Analog Select)............................. 115
ANSELB (PORTB Analog Select)............................. 119
ANSELC (PORTC Analog Select) ............................ 123
APFCON (Alternate Pin Function Control) ............... 112
BAUDCON (Baud Rate Control)............................... 248
BORCON Brown-out Reset Control) .......................... 67
CLCDATA (Data Output) .......................................... 285
CLCxCON (CLCx Control)........................................ 277
CLCxGLS0 (Gate 1 Logic Select)............................. 281
CLCxGLS1 (Gate 2 Logic Select)............................. 282
CLCxGLS2 (Gate 3 Logic Select)............................. 283
CLCxGLS3 (Gate 4 Logic Select)............................. 284
CLCxPOL (Signal Polarity Control)........................... 278
CLCxSEL0 (Multiplexer Data 1 and 2 Select)........... 279
CMOUT (Comparator Output) .................................. 160
CMxCON0 (Cx Control) ............................................ 159
CMxCON1 (Cx Control 1) ......................................... 160
Configuration Word 1.................................................. 44
Configuration Word 2.................................................. 45
Core Function, Summary............................................ 28
CWGxCON0 (CWG Control 0) ................................. 307
CWGxCON1 (CWG Control 1) ................................. 308
CWGxCON2 (CWG Control 1) ................................. 309
CWGxDBF (CWGx Dead Band Falling Count)......... 310
CWGxDBR (CWGx Dead Band Rising Count) ......... 310
DACCON0 ................................................................ 152
DACCON1 ................................................................ 152
Device ID .................................................................... 47
FVRCON................................................................... 132
INTCON (Interrupt Control)......................................... 78
IOCAF (Interrupt-on-Change PORTA Flag).............. 127

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
IOCAN (Interrupt-on-Change PORTA
Negative Edge) ................................................. 127
IOCAP (Interrupt-on-Change PORTA
Positive Edge)................................................... 127
IOCBF (Interrupt-on-Change PORTB Flag).............. 128
IOCBN (Interrupt-on-Change PORTB
Negative Edge) ................................................. 128
IOCBP (Interrupt-on-Change PORTB
Positive Edge)................................................... 128
LATA (Data Latch PORTA)....................................... 115
LATB (Data Latch PORTB)....................................... 119
LATC (Data Latch PORTC) ...................................... 122
NCOxACCH (NCOx Accumulator High Byte) ........... 294
NCOxACCL (NCOx Accumulator Low Byte)............. 294
NCOxACCU (NCOx Accumulator Upper Byte)......... 294
NCOxCLK (NCOx Clock Control) ............................. 293
NCOxCON (NCOx Control) ...................................... 293
NCOxINCH (NCOx Increment High Byte)................. 295
NCOxINCL (NCOx Increment Low Byte) .................. 295
OPTION_REG (OPTION) ......................................... 165
OSCCON (Oscillator Control) ..................................... 62
OSCSTAT (Oscillator Status) ..................................... 63
PCON (Power Control Register) ................................. 71
PCON (Power Control) ............................................... 71
PIE1 (Peripheral Interrupt Enable 1)........................... 79
PIE2 (Peripheral Interrupt Enable 2)........................... 80
PIE3 (Peripheral Interrupt Enable 3)........................... 81
PIR1 (Peripheral Interrupt Register 1) ........................ 82
PIR2 (Peripheral Interrupt Request 2) ........................ 83
PIR3 (Peripheral Interrupt Request 3) ........................ 84
PMADRL (Program Memory Address)...................... 108
PMCON1 (Program Memory Control 1).................... 109
PMCON2 (Program Memory Control 2).................... 110
PMDATH (Program Memory Data) ........................... 108
PMDATL (Program Memory Data)............................ 108
PMDRH (Program Memory Address) ....................... 108
PORTA...................................................................... 114
PORTB...................................................................... 118
PORTC ..................................................................... 122
PWMxCON (PWM Control)....................................... 269
PWMxDCH (PWM Control)....................................... 270
PWMxDCL (PWM Control) ....................................... 270
RCREG ..................................................................... 254
RCSTA (Receive Status and Control)....................... 247
SPBRGH................................................................... 249
SPBRGL ................................................................... 249
Special Function, Summary ........................................ 29
SSPxADD (MSSPx Address and Baud Rate,
I2C Mode) ......................................................... 235
SSPxCON1 (MSSPx Control 1) ................................ 232
SSPxCON2 (SSPx Control 2) ................................... 233
SSPxCON3 (SSPx Control 3) ................................... 234
SSPxMSK (SSPx Mask) ........................................... 235
SSPxSTAT (SSPx Status) ........................................ 231
STATUS...................................................................... 21
T1CON (Timer1 Control)........................................... 175
T1GCON (Timer1 Gate Control) ............................... 176
T2CON...................................................................... 181
TRISA (Tri-State PORTA)......................................... 114
TRISB (Tri-State PORTB)......................................... 118
TRISC (Tri-State PORTC) ........................................ 122
TXSTA (Transmit Status and Control) ...................... 246
VREGCON (Voltage Regulator Control) ..................... 90
WDTCON (Watchdog Timer Control) ......................... 93
WPUA (Weak Pull-up PORTA) ................................. 116

2011 Microchip Technology Inc.

WPUB (Weak Pull-up PORTB)................................. 120

RESET.............................................................................. 325
Reset .................................................................................. 65
Reset Instruction................................................................. 68
Resets ................................................................................ 65
Associated Registers.................................................. 72
Revision History................................................................ 373

S
Software Simulator (MPLAB SIM) .................................... 361
SPBRG Register................................................................. 30
SPBRGH Register ............................................................ 249
SPBRGL Register............................................................. 249
Special Function Registers (SFRs)..................................... 29
SPI Mode (MSSPx)
Associated Registers................................................ 193
SPI Clock.................................................................. 189
SSPOV ............................................................................. 220
SSPOV Status Flag .......................................................... 220
SSPxADD Register........................................................... 235
SSPxCON1 Register ........................................................ 232
SSPxCON2 Register ........................................................ 233
SSPxCON3 Register ........................................................ 234
SSPxMSK Register........................................................... 235
SSPxSTAT Register ......................................................... 231
R/W Bit ..................................................................... 198
Stack................................................................................... 36
Accessing ................................................................... 36
Reset .......................................................................... 38
Stack Overflow/Underflow .................................................. 68
STATUS Register ............................................................... 21
SUBWFB .......................................................................... 327

T
T1CON Register ......................................................... 29, 175
T1GCON Register ............................................................ 176
T2CON (Timer2) Register................................................. 181
T2CON Register ................................................................. 29
Temperature Indicator
Associated Registers................................................ 134
Temperature Indicator Module.......................................... 133
Thermal Considerations.................................................... 340
Timer0 .............................................................................. 163
Associated Registers................................................ 165
Operation.................................................................. 163
Specifications ........................................................... 346
Timer1 .............................................................................. 167
Associated registers ................................................. 177
Asynchronous Counter Mode ................................... 169
Reading and Writing ......................................... 169
Clock Source Selection ............................................ 168
Interrupt .................................................................... 171
Operation.................................................................. 168
Operation During Sleep ............................................ 171
Prescaler .................................................................. 169
Specifications ........................................................... 346
Timer1 Gate
Selecting Source .............................................. 169
TMR1H Register....................................................... 167
TMR1L Register ....................................................... 167
Timer2 .............................................................................. 179
Associated registers ................................................. 182
Timers
Timer1
T1CON ............................................................. 175
T1GCON........................................................... 176

Preliminary

DS41609A-page 379

PIC16(L)F1508/9
Timer2
T2CON.............................................................. 181
Timing Diagrams
A/D Conversion ......................................................... 347
A/D Conversion (Sleep Mode) .................................. 348
Acknowledge Sequence ........................................... 222
Asynchronous Reception .......................................... 244
Asynchronous Transmission ..................................... 240
Asynchronous Transmission (Back to Back) ............ 240
Auto Wake-up Bit (WUE) During Normal Operation . 256
Auto Wake-up Bit (WUE) During Sleep .................... 256
Automatic Baud Rate Calibration .............................. 254
Baud Rate Generator with Clock Arbitration ............. 215
BRG Reset Due to SDA Arbitration During Start
Condition........................................................... 226
Brown-out Reset (BOR) ............................................ 344
Brown-out Reset Situations ........................................ 67
Bus Collision During a Repeated Start Condition
(Case 1) ............................................................ 227
Bus Collision During a Repeated Start Condition
(Case 2) ............................................................ 227
Bus Collision During a Start Condition (SCL = 0) ..... 226
Bus Collision During a Stop Condition (Case 1) ....... 228
Bus Collision During a Stop Condition (Case 2) ....... 228
Bus Collision During Start Condition (SDA only) ...... 225
Bus Collision for Transmit and Acknowledge............ 224
CLKOUT and I/O....................................................... 343
Clock Synchronization .............................................. 212
Clock Timing ............................................................. 342
Comparator Output ................................................... 153
Fail-Safe Clock Monitor (FSCM) ................................. 61
First Start Bit Timing ................................................. 216
I2C Bus Data ............................................................. 354
I2C Bus Start/Stop Bits.............................................. 354
I2C Master Mode (7 or 10-Bit Transmission) ............ 219
I2C Master Mode (7-Bit Reception) ........................... 221
I2C Stop Condition Receive or Transmit Mode ......... 223
INT Pin Interrupt.......................................................... 76
Internal Oscillator Switch Timing................................. 56
Repeat Start Condition.............................................. 217
Reset Start-up Sequence............................................ 69
Reset, WDT, OST and Power-up Timer ................... 344
Send Break Character Sequence ............................. 257
SPI Master Mode (CKE = 1, SMP = 1) ..................... 351
SPI Mode (Master Mode) .......................................... 189
SPI Slave Mode (CKE = 0) ....................................... 352
SPI Slave Mode (CKE = 1) ....................................... 352
Synchronous Reception (Master Mode, SREN) ....... 261
Synchronous Transmission....................................... 259
Synchronous Transmission (Through TXEN) ........... 259
Timer0 and Timer1 External Clock ........................... 345
Timer1 Incrementing Edge........................................ 171
Two Speed Start-up .................................................... 59
USART Synchronous Receive (Master/Slave) ......... 350
USART Synchronous Transmission
(Master/Slave)................................................... 350
Wake-up from Interrupt ............................................... 88
Timing Parameter Symbology........................................... 341
Timing Requirements
I2C Bus Data ............................................................. 355
I2C Bus Start/Stop Bits ............................................. 354
SPI Mode .................................................................. 353
TMR0 Register .................................................................... 29
TMR1H Register ................................................................. 29
TMR1L Register .................................................................. 29

DS41609A-page 380

TMR2 Register.................................................................... 29
TRIS.................................................................................. 328
TRISA Register........................................................... 29, 114
TRISB Register........................................................... 29, 118
TRISC ............................................................................... 121
TRISC Register........................................................... 29, 122
Two-Speed Clock Start-up Mode........................................ 58
TXREG ............................................................................. 239
TXREG Register ................................................................. 30
TXSTA Register.......................................................... 30, 246
BRGH Bit .................................................................. 249

U
USART
Synchronous Master Mode
Requirements, Synchronous Receive .............. 350
Requirements, Synchronous Transmission...... 350
Timing Diagram, Synchronous Receive ........... 350
Timing Diagram, Synchronous Transmission... 350

V
VREF. SEE ADC Reference Voltage
VREGCON Register ........................................................... 90

W
Wake-up on Break ............................................................ 255
Wake-up Using Interrupts ................................................... 87
Watchdog Timer (WDT)...................................................... 68
Associated Registers .................................................. 94
Modes ......................................................................... 92
Specifications ........................................................... 345
WCOL ....................................................... 215, 218, 220, 222
WCOL Status Flag.................................... 215, 218, 220, 222
WDTCON Register ............................................................. 93
WPUA Register................................................................. 116
WPUB Register................................................................. 120
Write Protection .................................................................. 46
WWW Address ................................................................. 381
WWW, On-Line Support ....................................................... 8

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
THE MICROCHIP WEB SITE

CUSTOMER SUPPORT

Microchip provides online support via our WWW site at

www.microchip.com. This web site is used as a means
to make files and information easily available to
customers. Accessible by using your favorite Internet
browser, the web site contains the following
information:

Users of Microchip products can receive assistance

through several channels:

Product Support Data sheets and errata,

application notes and sample programs, design
resources, users guides and hardware support
documents, latest software releases and archived
software
General Technical Support Frequently Asked
Questions (FAQ), technical support requests,
online discussion groups, Microchip consultant
program member listing
Business of Microchip Product selector and
ordering guides, latest Microchip press releases,
listing of seminars and events, listings of
Microchip sales offices, distributors and factory
representatives

Distributor or Representative
Local Sales Office
Field Application Engineer (FAE)
Technical Support
Development Systems Information Line

Customers
should
contact
their
distributor,
representative or field application engineer (FAE) for
support. Local sales offices are also available to help
customers. A listing of sales offices and locations is
included in the back of this document.
Technical support is available through the web site
at: http://microchip.com/support

CUSTOMER CHANGE NOTIFICATION

SERVICE
Microchips customer notification service helps keep
customers current on Microchip products. Subscribers
will receive e-mail notification whenever there are
changes, updates, revisions or errata related to a
specified product family or development tool of interest.
To register, access the Microchip web site at
www.microchip.com. Under Support, click on
Customer Change Notification and follow the
registration instructions.

2011 Microchip Technology Inc.

Preliminary

DS41609A-page 381

PIC16(L)F1508/9
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip
product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our
documentation can better serve you, please FAX your comments to the Technical Publications Manager at
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Please list the following information, and use this outline to provide us with your comments about this document.
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Application (optional):
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Device: PIC16(L)F1508/9

Literature Number: DS41609A

Questions:
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2. How does this document meet your hardware and software development needs?

3. Do you find the organization of this document easy to follow? If not, why?

4. What additions to the document do you think would enhance the structure and subject?

5. What deletions from the document could be made without affecting the overall usefulness?

6. Is there any incorrect or misleading information (what and where)?

7. How would you improve this document?

DS41609A-page 382

Preliminary

2011 Microchip Technology Inc.

PIC16(L)F1508/9
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.

[X](1)

PART NO.
Device

Tape and Reel Temperature

Option
Range

/XX

XXX

Package

Pattern

Examples:
a)

b)
Device:

PIC16F1508, PIC16LF1508,
PIC16F1509, PIC16LF1509

Tape and Reel

Option:

Blank
T

= Standard packaging (tube or tray)

= Tape and Reel(1)

Temperature
Range:

I
E

= -40C to +85C
= -40C to +125C

Package:

ML
P
SO
SS

Pattern:

=
=
=
=

(Industrial)
(Extended)

Micro Lead Frame (QFN) 4x4

Plastic DIP
SOIC
SSOP

QTP, SQTP, Code or Special Requirements

(blank otherwise)

2011 Microchip Technology Inc.

PIC16LF1508T - I/SO
Tape and Reel,
Industrial temperature,
SOIC package
PIC16F1509 - I/P
Industrial temperature
PDIP package
PIC16F1508 - E/ML
Extended temperature,
QFN package
QTP pattern #298

Preliminary

Note 1:

Tape and Reel identifier only appears in the

catalog part number description. This
identifier is used for ordering purposes and is
not printed on the device package. Check
with your Microchip Sales Office for package
availability with the Tape and Reel option.

DS41609A-page 383

Worldwide Sales and Service

AMERICAS

ASIA/PACIFIC

EUROPE

Corporate Office
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://www.microchip.com/
support
Web Address:
www.microchip.com

Asia Pacific Office

Suites 3707-14, 37th Floor
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Fax: 852-2401-3431

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Fax: 91-80-3090-4123
India - New Delhi
Tel: 91-11-4160-8631
Fax: 91-11-4160-8632

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Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
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Fax: 81-45-471-6122

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Tel: 49-89-627-144-0
Fax: 49-89-627-144-44

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Tel: 82-53-744-4301
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Italy - Milan
Tel: 39-0331-742611
Fax: 39-0331-466781

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Tel: 678-957-9614
Fax: 678-957-1455
Boston
Westborough, MA
Tel: 774-760-0087
Fax: 774-760-0088
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Fax: 630-285-0075
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Santa Clara, CA
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Fax: 408-961-6445
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Mississauga, Ontario,
Canada
Tel: 905-673-0699
Fax: 905-673-6509

Australia - Sydney
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
China - Beijing
Tel: 86-10-8569-7000
Fax: 86-10-8528-2104
China - Chengdu
Tel: 86-28-8665-5511
Fax: 86-28-8665-7889
China - Chongqing
Tel: 86-23-8980-9588
Fax: 86-23-8980-9500

Korea - Seoul
Tel: 82-2-554-7200
Fax: 82-2-558-5932 or
82-2-558-5934

China - Hangzhou
Tel: 86-571-2819-3187
Fax: 86-571-2819-3189

Malaysia - Kuala Lumpur

Tel: 60-3-6201-9857
Fax: 60-3-6201-9859

China - Hong Kong SAR

Tel: 852-2401-1200
Fax: 852-2401-3431

Malaysia - Penang
Tel: 60-4-227-8870
Fax: 60-4-227-4068

China - Nanjing
Tel: 86-25-8473-2460
Fax: 86-25-8473-2470

Philippines - Manila
Tel: 63-2-634-9065
Fax: 63-2-634-9069

China - Qingdao
Tel: 86-532-8502-7355
Fax: 86-532-8502-7205

Singapore
Tel: 65-6334-8870
Fax: 65-6334-8850

China - Shanghai
Tel: 86-21-5407-5533
Fax: 86-21-5407-5066

Taiwan - Hsin Chu

Tel: 886-3-5778-366
Fax: 886-3-5770-955

China - Shenyang
Tel: 86-24-2334-2829
Fax: 86-24-2334-2393

Taiwan - Kaohsiung
Tel: 886-7-536-4818
Fax: 886-7-330-9305

China - Shenzhen
Tel: 86-755-8203-2660
Fax: 86-755-8203-1760

Taiwan - Taipei
Tel: 886-2-2500-6610
Fax: 886-2-2508-0102

China - Wuhan
Tel: 86-27-5980-5300
Fax: 86-27-5980-5118

Thailand - Bangkok
Tel: 66-2-694-1351
Fax: 66-2-694-1350

Spain - Madrid
Tel: 34-91-708-08-90
Fax: 34-91-708-08-91
UK - Wokingham
Tel: 44-118-921-5869
Fax: 44-118-921-5820

China - Xian
Tel: 86-29-8833-7252
Fax: 86-29-8833-7256
China - Xiamen
Tel: 86-592-2388138
Fax: 86-592-2388130
China - Zhuhai
Tel: 86-756-3210040
Fax: 86-756-3210049

DS41609A-page 384

Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340

08/02/11

Preliminary

2011 Microchip Technology Inc.

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