12F683 ADcin = binary outcome!

[HankMcSpank]

I'm a struggling learner who took a few months out of all this - I wish I hadn't now!

Anyway, I'm re-starting with a different (simpler!) chip - a 12f683 - just getting back to the basics right now....AtoD.

I found some code posted by Bruce on here that I shamelessly used (changing the pins to suit my setup)...




@MyConfig = _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON
@MyConfig = MyConfig & _MCLRE_OFF

CMCON0 = 7 ' Disable comparator
ANSEL = %00000010 ' Set GPIO.1 to A/D
ADCON0.7 = 1 ' Right justify for 10-bit
TRISIO = %00000010 ' GP.0 = serial out, GPIO.1 = A/D in, rest outputs

DEFINE OSC 8 ' Internal 8MHz

DEFINE DEBUG_REG GPIO ' Define DEBUG port
DEFINE DEBUG_BIT 0 ' Set GPIO.0 as DEBUG serial output pin
DEFINE DEBUG_BAUD 9600 ' DEBUG baud rate = 9600 bps
DEFINE DEBUG_MODE 0 ' 1 = inverted, 0 = true

DEFINE ADC_BITS 10 ' 10-bit resolution
DEFINE ADC_CLOCK 5 ' Set clock source to Frc/16
DEFINE ADC_SAMPLEUS 50 ' Sample time in uS before A/D is started
Quanta CON 1251 ' For 10-bit A/D +Vref = 5V : 5V/1023*256=1.251=Quanta

' PIN# NAME USE & CONNECTION
' 1 Vdd +5VDC power supply
' 2 GPIO.5 N/C (N/C = NO CONNECTION)
' 3 GPIO.4 N/C
' 4 GPIO.3 N/C
' 5 GPIO.2 N/C
' 6 GPIO.1 A/D input pin
' 7 GPIO.0 Serial output pin to PC serial port RX pin
' 8 Vss Power supply ground (also connect to DB-9 pin #5)
'-------------------------------------------------------------------------

ADval VAR WORD ' A/D result


MAIN:
ADCIN 1, ADval ' Read A/D
DEBUG DEC ADval DIG 3,".",DEC3 ADval,"V",13, 10
PAUSE 500
GOTO MAIN
END



the thing is it'll read 5V for 0V presented on pin 6 GP1 (I view the AtoD result using the PICkit 2 Usart tool)- but nothing in between (only two states!)

Any ideas please before I just give this all up as a bad job and turn to constructing replica stately homes out of discarded matchsticks.

[Archangel]

Hi Hank. . .
try ADCON0 = %10000111
it POR defaults to 0 0 0 0 0 0 0 0

Bits 3:2
00 = GPIO.0 AN0
01 = GPIO.1 AN1
10 = GPIO.2 AN2
11 = GPIO.3 AN3
Bits 1:0
Bit 0 , 0 = disabled 1 = enabled
Bit 1, 0 = A/D completed or not in progress 1 = ready to do for you

[HankMcSpank]

Hi Joe,

I tried your recommendation - couldn't get it to work.

I think it might be something to do with leaving the Pickit2 programmer attached as a 'virtual' serial connnection to my PC - so I moved the AtoD over to AN3 (pin 3)..

This code seems to work...




@MyConfig = _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON
@MyConfig = MyConfig & _MCLRE_OFF

DEFINE OSC 4 ' Internal 8MHz
DEFINE ADC_BITS 8 ' 8-bit resolution
DEFINE ADC_CLOCK 2 ' Set clock source to Frc/32
DEFINE ADC_SAMPLEUS 50 ' Sample time in uS before A/D conversion is started

CMCON0 = 7 'Comparators off
ADCON0 = %00000001 'ADC enabled and right justified
ANSEL = %00001000 'GPIO.0 and GPIO.1 analog input
INTCON = 0 'INTERRUPTS off
TRISIO = %111011 'GPIO2 output
GPIO = %00010000 ' All outputs = 0 on boot

Quanta CON 1251 ' For 10-bit A/D +Vref = 5V : 5V/1023*256=1.251=Quanta
ADval VAR WORD ' A/D conversion result

DEFINE DEBUG_REG GPIO ' Define DEBUG port
DEFINE DEBUG_BIT 0 ' Set GPIO.0 as DEBUG serial output pin
DEFINE DEBUG_BAUD 9600 ' DEBUG baud rate = 9600 bps
DEFINE DEBUG_MODE 0 ' 1 = inverted, 0 = true

MAIN:
ADCIN 3, ADval ' Read A/D
DEBUG DEC ADvAL,13 ,10
PAUSE 200
GOTO MAIN

END



Many thanks for your help.

[Archangel]

Hi Joe,

I tried your recommendation - couldn't get it to work.

I think it might be something to do with leaving the Pickit2 programmer attached as a 'virtual' serial connnection to my PC - so I moved the AtoD over to AN3 (pin 3)..

This code seems to work...




@MyConfig = _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON
@MyConfig = MyConfig & _MCLRE_OFF

DEFINE OSC 4 ' Internal 8MHz
DEFINE ADC_BITS 8 ' 8-bit resolution
DEFINE ADC_CLOCK 2 ' Set clock source to Frc/32
DEFINE ADC_SAMPLEUS 50 ' Sample time in uS before A/D conversion is started

CMCON0 = 7 'Comparators off
ADCON0 = %00000001 'ADC enabled and right justified
ANSEL = %00001000 'GPIO.0 and GPIO.1 analog input
INTCON = 0 'INTERRUPTS off
TRISIO = %111011 'GPIO2 output
GPIO = %00010000 ' All outputs = 0 on boot

Quanta CON 1251 ' For 10-bit A/D +Vref = 5V : 5V/1023*256=1.251=Quanta
ADval VAR WORD ' A/D conversion result

DEFINE DEBUG_REG GPIO ' Define DEBUG port
DEFINE DEBUG_BIT 0 ' Set GPIO.0 as DEBUG serial output pin
DEFINE DEBUG_BAUD 9600 ' DEBUG baud rate = 9600 bps
DEFINE DEBUG_MODE 0 ' 1 = inverted, 0 = true

MAIN:
ADCIN 3, ADval ' Read A/D
DEBUG DEC ADvAL,13 ,10
PAUSE 200
GOTO MAIN

END

Many thanks for your help.
OK, if you are going to use @MyConfig, you are missing the most important piece, under @myConfig you must have the config statement directing it to use MYConfig
like so:


@_MyConfig = _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON
@_MyConfig = MyConfig & _MCLRE_OFF
@ __config MyConfig
And @ _MyConfig must have 1 underscore and no spaces between the @ symbol and the underscore.
I suspect if that worked for you then doing it this way will give an overwriting previous address error, because your code is still using the default config.