599 Menlo Drive, Suite 100
General: info@parallax.com
Rocklin, California 95765, USA
Technical: support@parallax.com
Office: (916) 624-8333
Web Site: www.parallax.com
Fax: (916) 624-8003
Educational: www.parallax.com/sic
BS2pe Data Logger Application Note
Parts used:
• BS2pe (#BS2PE)
• BS2p24 demo board (#45183) (suggested but not required)
• Parallel LCD (#603-00006)
• DS1822 (#604-00013)
• Push button (#400-00001)
• 10k ohm resistor (#150-01030)
• 4.7k ohm resistor (#150-04720)
General Information
The following code and setup will implement the BS2pe
features of data logging, Parallel LCD interface, and
expanded EEprom.
Control from a BASIC Stamp
For easy wiring of the LCD, Parallax would suggest the BS2p24 demo board, but it is not required. The
wiring for the LCD does require numerous I/O pins as seen below. If you use the demo board then you
will not need to wire the LCD section below.
DB7
P7
DB6
P6
DB5
P5
DB4
P4 NOTE: Potentiometer between
E
P0 LCD pin 3 and ground is for
R/W
P2 optional contrast control.
RS
P3 10 kΩ
Vdd Connect LCD pin 3 directly to
ground for maximum contrast.
Vss Vdd
1 2 3 4 5 6 7 8 9 11 12 13 14
10 kΩ
P13
Vss
Parallax, Inc. • BS2pe data logger Version 1.0 Page 1
Vdd
DS1822
4.7 kΩ
Vdd
DQ P15
GND
Vss
' Temp_lcd_data_demo.bs2
' Purpose... Reads and displays information from a Dallas DS1822,and stores data across memory
blocks.
' {$STAMP BS2pe}
' {$PBASIC 2.5}
' -----[ Declarations ]----------------------------------------------------
OWpin CON 15
LCDpin CON 0
NoCmd CON $00 ' No command in LCDOUT
ClrLCD CON $01 ' clear the LCD
CrsrHm CON $02 ' move cursor to home position
CrsLf CON $10 ' move cursor left
CrsRt CON $14 ' move cursor right
DispLf CON $18 ' shift displayed chars left
DispRt CON $1C ' shift displayed chars right
DDRam CON $80 ' Display Data RAM control
CGRam CON $40 ' Custom character RAM
Line1 CON $80 ' DDRAM address of line 1
Line2 CON $C0 ' DDRAM address of line 2
UNit_off CON $08
Unit_on CON $0d
OW_FERst CON %0001 ' Front-End Reset
OW_BERst CON %0010 ' Back-End Reset
OW_BitMode CON %0100
OW_HighSpd CON %1000
ReadROM CON $33 ' read ID, serial num, CRC
MatchROM CON $55 ' look for specific device
SkipROM CON $CC ' skip rom (one device)
SearchROM CON $F0 ' search
CnvrtTemp CON $44 ' do temperature conversion
RdScratch CON $BE ' read scratchpad
NoDevice CON %11 ' no device present
DS1822 CON $22 ' device code
DegSym CON 176
DevCheck VAR Nib ' device check return ocde
Idx VAR Byte ' loop counter
RomData VAR Byte(8) ' ROM data from DS1820
TempIn VAR Word ' raw temperature
Sign VAR tempIn.Bit11 ' 1 = negative temperature
TLo VAR tempIn.LowByte
THi VAR tempIn.HighByte
TSign VAR Bit
TempF VAR Word ' Fahrenheit
TempC VAR Word ' Celsius
Run_bit VAR Word
Bank VAR Byte 'bank address
Address VAR Word 'address
Readings VAR Word 'Readings
Temp VAR Word 'Work space varablie
' -----[ Initialization ]--------------------------------------------------
'
Initialize:
PAUSE 500 ' let the LCD settle
LCDCMD LCDpin,%00110000 : PAUSE 5 ' 8-bit mode
LCDCMD LCDpin,%00110000 : PAUSE 0
LCDCMD LCDpin,%00110000 : PAUSE 0
LCDCMD LCDpin,%00100000 : PAUSE 0 ' 4-bit mode
LCDCMD LCDpin,%00001100 : PAUSE 0 ' no crsr, no blink
LCDCMD LCDpin,%00000110 : PAUSE 0 ' inc crsr, no disp shift
LCDCMD LCDpin,%00101000 : PAUSE 0 ' 2 Line 5x8 font
Parallax, Inc. • BS2pe data logger Version 1.0 Page 2
LCDCMD LCDpin,ClrLCD
pause 1000
' -----[ Main Routine ]----------------------------------------------------
Bank = 1
Main:
IF run_bit = 1 then Display_Temperatures
GOSUB Device_Check ' look for device
IF (devCheck <> NoDevice) THEN Get_ROM
No_Device_Found:
LCDOUT LCDpin,Line1,[" No DS1822"] : PAUSE 5
LCDOUT LCDpin,Line2,[" Present"]
PAUSE 1500
LCDCMD LCDpin,ClrLCD : PAUSE 0
LCDOUT LCDpin,Line1,["Insert Ds1822"] : PAUSE 5
LCDOUT LCDpin,Line2,["and reset stamp"]
PAUSE 1500
LCDCMD LCDpin,ClrLCD : PAUSE 0
goto main
Get_ROM:
OWOUT OWpin,OW_FERst,[ReadROM] ' send Read ROM command
OWIN OWpin,OW_BERst,[STR romData\8] ' read serial number & CRC
IF (romData(0) = DS1822) THEN Show_Data
LCDCMD LCDpin,ClrLCD : PAUSE 0
LCDOUT LCDpin,Line1,["Installed device"]
PAUSE 5
LCDOUT LCDpin,Line2,["is not DS1822"] : PAUSE 5
LCDOUT LCDpin,NoCmd,["Code = ",HEX2 romData(0)]
PAUSE 1500
goto main
Show_Data:
LCDCMD LCDpin,ClrLCD : PAUSE 0
LCDOUT LCDpin,Line1,["DS1822 Data"]
PAUSE 1500
LCDCMD LCDpin,ClrLCD : PAUSE 0
LCDOUT LCDpin,Line1,["Serial Number : "] : PAUSE 5
FOR idx = 6 TO 1
LCDOUT LCDpin,Line2,[HEX2 romData(idx)]
NEXT
PAUSE 1500
LCDCMD LCDpin,ClrLCD : PAUSE 0
LCDOUT LCDpin,Line1,["Checksum : ",HEX2 romData(7)]
PAUSE 2000
Display_Temperatures:
run_bit = 1
GOSUB Get_Temp
LCDCMD LCDpin,ClrLCD : PAUSE 0
LCDOUT LCDpin,Line1,["Temp ","F:", SDEC tempF] : PAUSE 0
skip_over:
readings = tempF
IF in13 = 0 THEN full
GOSUB record
GOTO Main
' -----[ Subroutines ]-----------------------------------------------------
'
' This subroutine checks to see if any 1-Wire devices are present on the
' bus. It does NOT search for ROM codes
'
Device_Check:
devCheck = 0
OWOUT OWpin,OW_FERst,[SearchROM] ' reset and start search
OWIN OWpin,OW_BitMode,[devCheck.Bit1,devCheck.Bit0]
RETURN
Parallax, Inc. • BS2pe data logger Version 1.0 Page 3
Get_Temp:
FOR temp = 1 TO 250
OWOUT OWpin,OW_FERst,[SkipROM,CnvrtTemp] ' send conversion command
PAUSE 1 ' give it some time
NEXT
OWOUT OWpin,OW_FERst,[SkipROM,RdScratch] ' go get the temperature
OWIN OWpin,OW_BERst,[tLo,tHi]
tSign = sign ' save sign bit
tempC = tempIn
tempC = tempC >> 4 ' round to whole degrees
IF (tSign = 0) THEN NoNegC
tempC = tempC | $FF00 ' extend sign bits for negs
NoNegC:
tempF = tempC */ $01CD ' multiply by 1.8
IF tSign = 0 THEN NoNegF ' if neg, extend sign bits
tempF = tempF | $FF00
NoNegF:
tempF = tempF + 32 ' finish C -> F conversion
RETURN
Full:
FOR bank = 1 TO 15
FOR address = 0 TO 2048 step 2
STORE bank
READ address ,readings.lowbyte
READ address + 1,readings.highbyte
LCDCMD LCDpin,ClrLCD : PAUSE 0
LCDOUT LCDpin,Line1,["Reading: ",dec address/2] : PAUSE 0
LCDOUT LCDpin,Line2,["Bank:",dec bank,"Temp ","F:", SDEC tempF] : PAUSE 0
PAUSE 1000 ' lessen this pause to increase rate of display
NEXT
NEXT
Sleeping:
SLEEP 3
LCDCMD LCDpin,unit_off : PAUSE 0
IF IN12 = 1 THEN sleeping
LCDCMD LCDpin,unit_on : PAUSE 0
GOTO sleeping
Record:
PAUSE 1000 ‘Adjust to vary the rate of storage
If address < 2040 THEN no_up
bank = bank +1
address = 0
No_up:
'DEBUG 0,cr,"record: ",? bank,? address,? readings," Low ",dec readings.lowbyte," High
",dec readings.highbyte
STORE bank
WRITE address ,readings.lowbyte
WRITE address + 1,readings.highbyte
address = address + 2
IF bank = 15 AND address = 2040 THEN filled
return
filled:
LCDCMD LCDpin,ClrLCD : PAUSE 0
LCDOUT LCDpin,Line1,["Full"] : PAUSE 5
STOP
Parallax, Inc. • BS2pe data logger Version 1.0 Page 4
