Temperature Control system using 8086
AIM:-
To develop Temperature Control system using 8086
APPARATUS:-
Microprocessor trainer kit, Temperature controller kit, power supply, data cable etc.
THEORY:-
Temperature control system involved interfacing successive approximation ADC and typical
method of measuring and controlling the temperature using microprocessor. ADC is among the
most widely used devices for data acquisition. A digital computer uses binary values, but in
physical world everything is analog, temperature, pressure, humidity, and velocity are few
examples of physical quantities that we seal with every day.
Temperature measurement is of great importance in industry as most of the processes are
temperature dependent. A number of devices and schemes have been used over the years, for the
measurement of temperature. Typical sensors include devices like thermocouples, thermostats,
RTD’s and semiconductor sensor.
This system uses semiconductor sensor AD590 to monitor the temperature of water bath. The
AD590 is basically a PTAT (proportional to absolute temperature) current regulator. It generates
a current O/P of 1µA/K above absolute zero temperature that is -2730C. Thus at 00C the current
O/P will be 273µA and 250 if will be 298µA and 373mV at 1000. This O/p is buffered through an
OPAMP having a gain of 10. To enable easy equivalence between the transducers O/P in volts and
the measured temperature a calibration procedure needs to be done.
WORKING:-
8255 is interfaced with 8086 in I/O mapped I/O. port A (PA0-PA7) as input port is connect to data
lines of ADC, PB0, PB1, PB2 lines of port B for channel selection, PC2 connected to Start of
conversion (SOC) and PC3 to O/P enable. Channel 1 of ADC is used to input analog signal,
Channel 0 of ADC for temperature controller.
ADC will give binary equivalent of the I/P voltage. Input will vary from 0 to 5V (0 to 100 degree
C) and the ADC O/P varies from 00-FFH. So 5V/100 i.e. 5000mvs/100 gives 50mvs/0C. And the
counts for indication of temperature are taken as 2.5 (256/100) per degree C.
AC supply to the external heating element is controlled through the onboard Relay, based on the
set value. When the temperature of the heating element (which is sensed by AD590, AD590 output
is analog which is converted to digital by ADC) is less than the set value (reference value) heating
element will be switched ON and when temperature crosses the set temperature AC supply is
turned OFF.
Interfacing Stepper Motor to 8086 using 8255
To Interface Stepper Motor to 8086 using 8255 and write Assembly Language Program to rotate
Stepper Motor in Clockwise & Anticlockwise direction.
APPARATUS:-
Microprocessor trainer kit, ADC kit, power supply, data cable etc
THEORY:-
Stepper motor is a device used to obtain an accurate position control of rotating shafts. A stepper
motor employs rotation of its shaft in terms of steps, rather than continuous rotation as in case of
AC or DC motor. To rotate the shaft of the stepper motor, a sequence of pulses is needed to be
applied to the windings of the stepper motor, in proper sequence. The numbers of pulses required
for complete rotation of the shaft of the stepper motor are equal to the number of internal teeth on
its rotor. The stator teeth and the rotor teeth lock with each other to fix a position of the shaft. With
a pulse applied to the winding input, the rotor rotates by one teeth position or an angle x. the angle
x may be calculated as.
x = 3600 / no. of rotor teeth
After the rotation of the shaft through angle x, the rotor locks itself with the next tooth in the
sequence on the internal surface of the stator. The typical schematic of a typical stepper motor with
four windings is as shown below.
The stepper motors have been designed to work with digital circuits. Binary level pulses of 0-5V
are required at its winding inputs to obtain the rotation of the shafts. The sequence of the pulses
can be decided, depending upon the required motion of the shaft. By suitable sequence of the
pulses the motor can be used in three modes of operation.
One phase ON (medium torque)
Two phase ON (high torque)
Half stepping (low torque)
WORKING:-
8255 is interfaced with 8086 in I/O mapped I/O. port C (PC0, PC1, PC2, PC3) is used to give pulse
sequence to stepper motor. The 8255 provides very less current which will not be able to drive
stepper motor coils so each of the winding of a stepper motor needs to be interfaced using high
speed switching Darlington transistors with max 1A, 80V rating with heat sink, with the output
port of 8255. Output the sequence in correct order to have the desired direction to rotate the motor.
Traffic light control system using 8086
AIM:-
To develop Traffic light Control system using 8086
APPARATUS:-
Microprocessor trainer kit, Traffic light controller kit, power supply, data cable etc
THEORY:-
Traffic light controller interface module is designed to simulate the function of four way traffic
light controller. Combinations of red, amber and green LED’s are provided to indicate Halt, Wait
and Go signals for vehicles. Combination of red and green LED’s are provided for pedestrian
crossing. 36 LED’s are arranged in the form of an intersection. A typical junction is represented
on the PCB with comprehensive legend printing.
At the left corner of each road, a group of five LED’s (red, amber and 3 green) are arranged in the
form of a T-section to control the traffic of that road. Each road is named North (N), South(S),
East (E) and West (W). LED’s L1, L10, L19 & L28 (Red) are for the stop signal for the vehicles
on the road N, S, W, & E respectively. L2, L11, L20 & L29 (Amber) indicates wait state for
vehicles on the road N, S, W, & E respectively. L3, L4 & L5 (Green) are for left, strait and right
turn for the vehicles on road S. similarly L12-L13-L14, L23-L22-L21 & L32-L31-L30 simulates
same function for the roads E, N, W respectively. A total of 16 LED’s (2 Red & 2 Green at each
road) are provided for pedestrian crossing. L7-L9.L16-L18, L25-L27 & L34-L36 (Green) when
on allows pedestrians to cross and L6-L8, L15-L17, L24-L26 & L33-L35 (Red) when on alarms
the pedestrians to wait.
To minimize the hardware pedestrian’s indicator LED’s (both red and green are connected to same
port lines (PC4 to PC7) with red inverted. Red LED’s L10 & L28 are connected to port lines PC2
& PC3 while L1 & L19 are connected to lines PC0 & PC1 after inversion. All other LED’s (amber
and green) are connected to port A & B.
WORKING:-
8255 is interfaced with 8086 in I/O mapped I/O and all ports are output ports. The basic operation
of the interface is explained with the help of the enclosed program. The enclosed program assumes
no entry of vehicles from North to West, from road East to South. At the beginning of the program
all red LED’s are switch ON, and all other LED‘s are switched OFF. Amber LED is switched ON
before switching over to proceed state from Halt state.
The sequence of traffic followed in the program is given below.
a) From road north to East
From road east to north
From road south to west
From road west to south
From road west to north
b) From road north to East
From road south to west
From road south to north
From road south to east
c) From road north to south
From road south to north
Pedestrian crossing at roads west & east
d) From road east to west
From road west to east
Pedestrian crossing at roads north & south
Interfacing ADC/DAC with 8086 Microprocessor
Signals in the real world are analog: light, sound, temperature, pressure, acceleration or other
phenomenon. So, real-world signals must be converted into digital, using a circuit called ADC
(Analog-to-Digital Converter), before they can be manipulated by digital equipment. When you
scan a picture with a scanner what the scanner is doing is an analog-to-digital conversion: it is
taking the analog information provided by the picture (light) and converting into digital. When you
record your voice on your computer, you are using an analog-to-digital converter to convert your
voice, which is analog, into digital information. When an audio CD is recorded at a studio, once
again analog-to-digital is taking place, converting sounds into digital numbers that will be stored
on the disc. Whenever we need the analog signal back, the opposite conversion – digital-to-analog,
which is done by a circuit called DAC, Digital-to-Analog Converter – is needed. When you play
an audio CD, what the CD player is doing is reading digital information stored on the disc and
converting it back to analog so you can hear the audio.
Analog-to-Digital converter with 8086 using 8255
AIM: - To Interface Analog-to-Digital converter to 8086 using 8255 and write Assembly Language
Program to read Digital value from ADC.
APPARATUS:-
Microprocessor trainer kit, ADC kit, power supply, data cable etc
THEORY:
ANALOG TO DIGITAL CONVERTER (ADC 0809):-
The ADC-0809 data acquisition component is a monolithic CMOS device with an 8-bit analog to
digital converter, 8 channel multiplexed control logic. The 8 bit A/D converter uses successive
approximation as the converter technique. The converter features a high impedance chopper
stabilized comparator, a 256R voltage divider with analog switch free and a successive
approximation register. The 8 channel multiplexed can directly access any of 8 single ended analog
signal.
FEATURES:-
1. Resolution 8 bits
2. Conversion time 100 micro sec.
3. Single supply 5V
4. 8 channel multiplexed with latched control logic
5. easy interface to all microprocessor
6. 0 to 5V analog input voltage range with single 5V supply
7. low power consumption 15mW
8. latched tristate output
WORKING:-
ADC interface consists of a NAND gate oscillator which feeds 50 KHz as the input clock to ADC,
input to channel is given through terminal blocks provided on the card. Channel selection is done
using port lines PC0, PC1 & PC2, START OF CONVERSION and ALE is controlled by port line
PC7. Converted digital output is read by ADC through PORTA lines by enabling OE. OE line is
connected to port line PC6.
In this method of interfacing microprocessor is continuously monitoring EOC line (which is
connected to port line PA7). When this goes high, make OE (PC6) high & then low, this will put
the digital equivalent of analog voltage of the given channel on data lines of ADC. Read the digital
data through port lines PA0 to PA7 and display the same data.
ADC 0809
The ADC0808, ADC0809 data acquisition component is a Monolithic CMOS device with an 8-
bit analog-to-digital converter, 8-channel multiplexer and microprocessor compatible control
logic. The 8-bit A/D converter uses successive approximations the conversion technique. The
converter features a high impedance chopper stabilized comparator, a 256R voltage divider with
analog switch tree and a successive approximation register.
INTERFACING ADC 0809 WITH 8086
8086 Microprocessors it doesn’t have an On chip ADC to accept the digital input, it will not accept
analog input, so we need a ADC to process the analog signal. For interfacing ADC 0809 we require
8 data lines. So ADC 0809 is an 8 bit ADC has 8 channels works on successive approximation
conversion technique
Questions;
Pin assignment with 8086, or pin diagram of ADC 0809
Circuit diagram to interface ADC 0809 with 8086
Assembly program to interface ADC 0809 with 8086
Interfacing Digital-To-Analog converter to 8086 using 8255
AIM:-
To Interface Digital -to-Analog converter to 8086 using 8255 and write Assembly Language
Program to generate Square Wave, Ramp Wave, Triangular Wave & Staircase Wave form.
APPARATUS:-
Microprocessor trainer kit, ADC kit, power supply, data cable, CRO etc
THEORY:-
The DAC 0800 is a monolithic 8 bit high speed current output digital to analog converters featuring
setting time of 100nSEC. It also features high compliance complementary current outputs to allow
differential output voltage of 20 Vp-p with simple resistor load and it can be operated both in
unipolar and bipolar mode.
FEATURES:-
1. Fast setting output current 100nS
2. Full scale error +/- 1 LSB
3. Complementary current outputs
4. easy interface to all microprocessor
5. Wide power supply range +/- 4.5 to +/- 18V
6. low power consumption
WORKING:-
When chip select of DAC is enabled then DAC will convert digital input value given through
portliness PB0-PB7 to analog value. The analog output from DAC is a current quantity. This
current is converted to voltage using OPAMP based current-to-voltage converter. The voltage
outputs (+/- 5V for bipolar 0 to 5V for unipolar mode) of OPAMP are connected to CRO to see
the wave form.
DAC 0800
DAC0800 series are monolithic 8-bit high-speed current output digital-to-analog converters
(DAC) featuring typical settling times of 100 ns. . The noise immune inputs will accept variety of
logic levels. The performance and characteristics of the device are essentially unchanged over the
±4.5V to ±18V power supply range and power consumption at only 33 mW with ±5V supplies is
independent of logic input levels.
INTERFACING DAC WITH 8086
We now want to we now want to convert the Digital signal to analog voltage by using 8086 trainer
board. Here we are using DAC 0800. The DAC 0800 consists of a 8 data lines and REF voltage
lines. When the DAC is given the digital input it converts the Digital data to corresponding current,
to convert the I to V we use UA 741.
Questions:
You have to tabulate the PIN assignment with 8086
Circuit diagram to interface DAC0800 with 8086
Assembly program to interface DAC with0800 with 8086
Interfacing LCD Module with 8086
AIM:-
To get familiar with LCD its pin configuration, internal architecture and its interface with
PPI 8255A.
APPARATUS:
PC having Intel microprocessor, MDA-8086 kit using WinnComm.
1-LCD:
16 CHARACTERS × 2 LINE MODULES
1) PHYSICAL DATA
Module size 80.0W × 36.0H × 9.30D mm
Min. view area 65.6W × 13.8D mm
Character construction 5 × 7 dots
Character size 2.85W × 3.8H mm
Character Pitch 3.65 mm
Dot size 0.55W × 0.5H mm
LCD(Liquid Crystal Display):
LCD (Liquid Crystal Display) is very popular for displaying in Embedded Applications. LCDs are
very cheap and easy to interface with microprocessors; LCDs are widely used in devices like
telephones, vending machines, washing machines, toys etc.
LCD comes in several varieties i.e. 16*2, 20*2, 20*4 etc. These different LCD varieties can display
different number of characters i.e. 16*2 can display 32 characters at a time.
Liquid Crystal displays are created by sandwiching a thin 10-12 µm layer of a liquid-crystal fluid
between two glass plates. A transparent, electrically conductive film or backplane is put on the
rear glass sheet. Transparent sections of conductive film in the shape of the desired characters are
coated on the front glass plate.
When a voltage is applied between a segment and the backplane, an electric field is created in the
region under the segment. This electric field changes the transmission of light through the region
under the segment film.
Characteristics:
Each module contains a CMOS controller and all necessary drivers which have low power
consumption. The controller is equipped with an internal character generator ROM, RAM and
RAM for display data. All display functions are controllable by instructions making interfacing
practical.
PIN CONFIGURATION:
There are total 16 pins in this LCD module.
Interfacing 7 segment Display with 8086 microprocessor
AIM:-
To get familiar with the seven segment display and its interfacing with 8086 microprocessor using
8255A.
APPARATUS:
PC having Intel microprocessor, MDA-8086 kit using WinnComm.
Theory
Seven segment is a display which may be either common anode or common cathode. Which is ON
either on 1 or zero but here we use the format ‘ON’ on zero (active low).
7-segment display, it is composed of 8 LEDs, 7 segments are arranged as a rectangle for symbol
displaying and there is an additional segment for decimal point displaying. In order to simplify
connecting, anodes and cathodes of all diodes are connected to the common pin so that there are
Common Anode displays.
Common Cathode displays.
Segments are marked with the letters from A to G, plus DP, as shown in the figure below. On
connecting, each diode is treated separately, which means that each must have its own current
limiting resistor.
A seven segment display, as its name indicates, is composed of seven elements. Individually on or
off, they can be combined to produce the representations numbers. In most applications, the seven
segments are of nearly uniform shape and size, though in the case of adding machines, the vertical
segments are longer and more oddly shaped at the ends in an effort to further enhance readability.
The hex decimal data corresponding to the segments which have to glow for displaying a character
is output to port B
As far we know all the segments are LEDs. Basically LED have Anode & Cathode. In order to
simplify connecting, anodes and cathodes of all diodes are connected to the common pin.
In Common Anode display, anodes of the all LEDs are connected to Vcc, cathodes are
connected to microprocessor port pins via 8255.
In Common Cathode display, cathodes of the all LEDs are connected to Gnd, anodes are
connected to microprocessor port pins via 8255.
DISPLAY FORMAT
Let us consider Common Anode display to understand well, the following table represents
the connection format of the Common Anode display
Logic ‘0' in the above format will turn ON that particular segment. Logic ‘1' will keep the
segment OFF. The data for turning ON the display is through 8255 (We already studied).
