by Richard Cooke.
I have attached the circuit diagram of what I have done the bit in the bottom left is an ADC test module that plugs on the ADC port of the PICAXE board it provides a 1 Hz square wave, a 2.7 volt zener a variable DC and the VCC to the 4 ADC inputs. The original output of port B was using a darlington pack as you may see in the picture I replaced that with a DIL resistor pack just to get the connectivity to the LCD port
I have also attached the test software for the PICAXE (see below) that allows the 4 push buttons to turn on the LEDs (PB4 repeats PB1 to upper LED) and sends my name to the screen.
The Picaxe development system is available as a free down load from
http://www.picaxe.com/Software/PICAXE/PICAXE-Programming-Editor/
#PICAXE 28x1 setfreq m8 EEPROM 0,("Richard Cooke V7") ' store the text in the EEPROM memory gosub init ;initialise LCD ;Use one byte for dir storage this sets part of Port C as input and part as Output: dirsc = %11110000 ' Set portc direction like this. out, out, out, out, in, in, in, in. symbol btn1 = pin0 symbol btn2 = pin1 symbol btn3 = pin2 symbol btn4 = pin3 symbol Mode = b27 low portc 7 low portc 6 low portc 5 low portc 4 Gosub LCD Main: Let b1 = 1 gosub wrins b0=0 loop11: lookup b0,("Select Mode"),b1 b0=b0+1 gosub wrchr if b0<11 then loop11 b1=192 'Select line 2 gosub wrins b0=0 loop14: lookup b0,("AWP AWF VTE O2"),b1 b0=b0+1 gosub wrchr if b0<14 then loop14 Pause 500 Main1: gosub Key_scan if mode = 1 then gosub AWP if mode = 4 then gosub O2 Goto Main1 ;Reads Buttons on the test module and lights LEDs Key_scan: If btn1 = 0 then high portc 4 endif If btn1 = 0 then let mode = 1 endif If btn1 = 1 then low portc 4 endif If btn2 = 0 then high portc 5 endif If btn2 = 0 then let mode = 2 endif If btn2 = 1 then low portc 5 endif If btn3 = 0 then high portc 6 endif If btn3 = 0 then let mode = 3 endif If btn3 = 1 then low portc 6 endif If btn4 = 0 then high portc 4 endif If btn4 = 0 then let mode = 4 endif If btn4 = 1 then low portc 4 endif Return '************************************************************************************ ' MEASURE Airway Oxygen Concentration '************************************************************************************ O2: Let b1 = 1 gosub wrins b0=0 loop15: lookup b0,("O2 Concentration"),b1 b0=b0+1 gosub wrchr if b0<16 then loop15 Pause 50 Oxygen: readadc 3,b0 w2=b0*100 'Scale ADC value to = 100% FSD default 100 w2=w2/50 'Scale ADC value to = 100% FSD default 100 w3=w2/100 ' w4=w2//100 w4=w4/10 w5=w2//10 w3=w3+48 'convert individual digits to ASCII w4=w4+48 w5=w5+48 b1=192 'Select line 2 gosub wrins ' ' b0=0 loop16: lookup b0,(" ",b6,b8,".",b10,"%"),b1 b0=b0+1 gosub wrchr if b0<7 then loop16 Gosub Key_scan if mode = 2 then goto main goto Oxygen '************************************************************************************ ' MEASURE Airway Pressure on ADC Channel 1 '************************************************************************************ AWP: low portc 4 Let b1 = 1 gosub wrins b0=0 loop12: lookup b0,("Airway Pressure "),b1 b0=b0+1 gosub wrchr if b0<15 then loop12 Pause 50 cmh2o: readadc 1,b0 w2=b0*40 'Scale ADC value to = 100cmH2O FSD default 100 w2=w2/102 'Scale ADC value to = 100cmH2O FSD default 100 w3=w2/100 ' w4=w2//100 w4=w4/10 w5=w2//10 w3=w3+48 'convert individual digits to ASCII w4=w4+48 w5=w5+48 b1=192 'Select line 2 gosub wrins ' 'Gosub Key_scan 'if mode = 1 then goto main ' b0=0 loop13: lookup b0,("cmH2O ",b6,b8,b10," "),b1 b0=b0+1 gosub wrchr if b0<12 then loop13 Gosub Key_scan if mode = 2 then goto main goto cmh2o '************************************************************************************ ' Opening Screen '************************************************************************************ LCD: let b1 = 1 ' set b1 to clear display instruction and "1" Sets Line 1 as the place to send text gosub wrins ' send instruction to LCD ' b1=192 would write to line 2 of a 16x 2 line display let b1 = 12 ' set b1 to hide cursor instruction gosub wrins ' send instruction to LCD For b0 = 0 to 15 ' For...next loop - Read "RichardCooke + Version " text into LCD read b0, b1 ' read letter from EEPROM into variable b1 gosub wrchr ' send character to LCD Next b0 ' Loop pause 6000 ' pause for 0.4s '************************************************************************************ ' MEASURE BATTERY VOLTS '************************************************************************************ '28X1 28 b0-27 w0-13 describes how the words are broken down into digit from the words to send 'first numbers then eventually text to the display battery: readadc 0,b0 'External resistors can be scaled to give a resulting 'count of around 120 for a 12volt battery-16K from +12volt to 'adc input 0 and 3K9 from adc input 3 to ground. In my Jig its direct to VCC but will not be true w2=b0*18 'adjust the division in this line to correct adc count by multiplication and then division so that w2=w2/100 'the display shows the correct voltage - change the division from 100 to 18 for 5V in this instance w3=w2/100 'Derive individual digits for display w4=w2//100 w4=w4/10 w5=w2//10 w3=w3+48 'convert individual digits to ASCII w4=w4+48 w5=w5+48 b1=192 'display message "BATTERY = ***V"at start of display line 2 'ASCII characters are formatted,punctuated,and labelled, gosub wrins 'and fed to 16 character X 2 line alphanumeric display- 'display starts at position 1- Display uses industry 'standard Hitachi HD44780 chip. Display format can be 'simply altered to accomodate 2X20,2X40,4X16 displays b0=0 loop10: lookup b0,("BATTERY=",b6,b8,".",b10,"V"),b1 b0=b0+1 gosub wrchr if b0<13 then loop10 pause 6000 'display battery volts for 1.5 seconds goto main '************************************************************************************ ' HD44780 LCD DISPLAY ROUTINES '************************************************************************************ '######################################################### '# Initialisation subprocedure for the LCD # # '# Use Port B For LCD # # '# B.7 - 14 (DB7) # # '# B.6 - 13 (DB6) # # '# B.5 - 12 (DB5) # # '# B.4 - 11 (DB4) # # '# B.2 - 4 (RS) # # '# B.3 - 6 (E) # # '######################################################### init: 'INITIALISE DISPLAY subroutine pins=0 'clear all output lines b0=0 'reset variable b0 pause 800 'wait 200ms for lcd to reset pins=48 'set to 8 bit operation pulsout 3,4 'send data by pulsing enable line pause 40 'wait 10ms pulsout 3,4 'send data by pulsing enable line pulsout 3,4 'send data by pulsing enable line let pins=32 'set to 4 bit operation pulsout 3,4 'send data by pulsing enable line pulsout 3,4 'send data by pulsing enable line let pins=128 'set to 2 line operation pulsout 3,4 'send data by pulsing enable line b1=14 'screen on, cursor on operation gosub wrins 'write instruction to lcd return 'return to main program wrchr: 'WRITE CHARACTER subroutine pins=b1&240 'mask high nibble of b1 into b2 high 2 'make sure RS is high(character mode) pause 4 pulsout 3,4 'send data by pulsing enable line b2=b1*16 'put low nibble of b1 into b2 pins=b2&240 'mask the high nibble of b2 high 2 'make sure RS is high pause 4 pulsout 3,4 'send data by pulsing enable line return 'return to main program wrins: 'WRITE INSTRUCTION subroutine pins=b1&240 'mask high nibble of b1 into b2 low 2 'make sure RS is low(instruction mode) pause 4 pulsout 3,4 'send data by pulsing enable line b2=b1*16 'put low nibble of b1 into b2 pins=b2&240 'mask the high nibble of b2 low 2 'make sure RS is low pause 4 pulsout 3,4 'send data by pulsing enable line high 2 'back to character mode pause 4 return 'return to main program
file: /Techref/io/lcd/PICAXEADCtest_rc.htm, 9KB, , updated: 2013/2/13 10:07, local time: 2024/8/14 20:16,
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