ADC on 12f675?

[peu]

I have the attached circuit and the following program:


TRISIO=%1 'Pic 12F675
DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 50
cmcon=7
ansel=1
ADCON0=131


number VAR word

Pause 100
Loop:

ADCIN 0, number ' (0-1023)

IF number > 0 AND number < 400 Then
GPIO.1=1
GPIO.2=0
GPIO.4=0
EndIF
IF number > 401 AND number < 800 Then
GPIO.1=0
GPIO.2=1
GPIO.4=0
EndIF
IF number > 801 AND number < 1024 Then
GPIO.1=0
GPIO.2=0
GPIO.4=1
EndIF


GoTo loop
End


it does not work, any ideas?

Im trying to do my 1st ADC program, a simpler working one that make me understand the concept is welcome too!!!


Thanks a bunch

[Dwayne]

Hello Peu,

Peu>>TRISIO=%1 'Pic 12F675<

TRISIO is your input output switch.

I did not go through all of your code, but this put a flag up to me.

TRISIO=%XXXXXXX is a binary representation of the switches.
I question the usagle of just TRISIO=%1

You are using GPIO.0 as your input, thus I would assign TRISIO one of the following:

TRISIO=%00000001
or
TRISIO=1

Notice I did not put the % in front of the second one.
Because 1 = %00000001

I am not saying this is your entire problem. But you may want to check it out.

Dwayne

[peu]

I tried but it did not worked, I think Im missing something, but I can't figure it out.

pointers to adc examples for the 12f675/683 are welcome. Thanks

[Acetronics2]

Hi,Peu

I remember CMCON = 7 is used on my 16F628 to DISABLE all Analogic inputs ...
Verify if the same config. word for 12F675...

your Pb seems to be here ...

Alain

[peu]

with this new header:

DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 50
'cmcon=7
ADCON0=%11000011 'dec 195
ansel=%001


it still does not work ... any idea?

[Bruce]

All you need to set is ADCON0.7 = 1 for right justification. PBP will
handle channel select bits and ADON.

Try this.

DEFINE ADC_BITS 10 
DEFINE ADC_CLOCK 3 
DEFINE ADC_SAMPLEUS 50 
number VAR word

CMCON = 7          ' Comparators off
ANSEL = %00000001  ' GPIO.0 A/D in, rest digital
ADCON0.7 = 1       ' Right justify for 10-bit
TRISIO = %00000001 ' GPIO.0 = input, rest outputs

    Pause 100

Loop:
    ADCIN 0, number ' (0-1023)
    IF (number > 0) AND (number < 400) Then
      GPIO 1=1
      GPIO.2=0
      GPIO.4=0
    EndIF
    IF (number > 401) AND (number < 800) Then
      GPIO.1=0
      GPIO.2=1
      GPIO.4=0
    EndIF
    IF (number > 801) AND (number < 1024) Then
      GPIO.1=0
      GPIO.2=0
      GPIO.4=1
    EndIF
    number = 0
    GoTo loop
    
    End

Assuming you have your config fuse options & oscillator setup
properly, this should work.

You can find several more 12F675 A/D examples here;
http://www.microengineeringlabs.com/...ples.htm#x4pbp

[Acetronics2]

here's an example ... with explanations !!!

Alain

[peu]

Bruce:

Thanks var word
loop:
thanks=$FFFF '


it works, now I need to adjust the code because the led dont work as expected, but I put a serout after the adcin and the terminal reads the different values OK!!!

goto loop

[Bruce]

DEFINE ADC_BITS 10 
DEFINE ADC_CLOCK 3 
DEFINE ADC_SAMPLEUS 50 
number VAR word

CMCON = 7          ' Comparators off
ANSEL = %00000001  ' GPIO.0 A/D in, rest digital
ADCON0.7 = 1       ' Right justify for 10-bit
GPIO = %00000000 ' Initialize outputs
TRISIO = %00000001 ' GPIO.0 = input, rest outputs

    PAUSE 100

Loop:
    ADCIN 0, number ' (0-1023)
    IF (number > 0) AND (number < 400) Then
      GPIO = %00000010
      'GPIO.1=1
      'GPIO.2=0
      'GPIO.4=0
    EndIF
    IF (number > 401) AND (number < 800) Then
      GPIO = %00000100
      'GPIO.1=0
      'GPIO.2=1
      'GPIO.4=0
    EndIF
    IF (number > 801) AND (number < 1024) Then
      GPIO = %00010000
      'GPIO.1=0
      'GPIO.2=0
      'GPIO.4=1
    EndIF
    number = 0
    GoTo loop