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.