I added a PICList tag so more people will see your question.

I don't see anything obviously wrong with the code you sent. It looks to me
like it is CCS's "C". If so, did you include a "use delay()" directive to
let the compiler know what speed oscillator you have.

You might want to try out the "EX_ADMM.C" sample included with CCS "C" to
see if that works. It should compile/run fine if you just change the
processor and speed directives to match the setup you have.

I've never used the "ICEPIC" emulator but, I have used a number of different
emulators over the years and have often found A/D conversion results
unreliable on emulators. Whenever I have questionable A/D results on an
emulator I first check the signal with a DMM and/or oscilloscope to make
sure the signal is what I expected. If the signal looks good I next try the
circuit with a programmed chip instead of the emulator.

One last thought, make sure your source impedance is 10K or less.

Paul

> -----Original Message-----
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Mccauley, Daniel H
> Sent: Friday, November 21, 2003 8:01 AM
>
> I am having some difficulty getting the A/D Converter in my
> PIC16C76 Emulated System (via ICEPIC).  I'm inputting a 0-5VDC
> voltage through a series 10 ohm
> resistor into Port A0 of my microcontroller which at the time is
> the ICEPIC emulator.
>
> The problem is that the voltage seems to be drifting all over the
> place and not settling.  I think it may either be a code problem
> on my part.
> In particular, the voltage seems to be constantly and slowly drifting up.
>
> The following subrouting is from my program.
>
> //*****************
>
> setup_adc_ports (ALL_ANALOG);
> setup_adc (ADC_CLOCK_INTERNAL);
> set_adc_channel ( 0 );
>
> while (TRUE)
>         {
>         value = read_adc ( ) ;
>         delay_ms (20);
>
>         *****routine here for displaying 8-bit A/D number on LCD*****
>         }
>
> Any thoughts???
>
> Thanks in advance!
> Dan

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