16F676 A/D not work!

[cindyw]

Hi, techies,

I am using 16F676 in my project. AN4 to AN7 need to be set to A/D.
Here is my code:

void init_adc(void)
{
SETUP_ADC_PORTS(sAN4|sAN5|sAN6|sAN7|VSS_VDD); // AN4:7 A/D. others digital,range 0-vdd ??
setup_adc( ADC_CLOCK_INTERNAL ); //internal 2-6us
set_adc_channel(TRIM); //channel 5
SETUP_COMPARATOR(NC_NC_NC_NC); // off comparators

}

The problem is that the resistance of all this pin is only 22ohm instead of high impedance as normal ADC. It results input analog signal pull down.
I check register: ANSEL=F0, ADCON0=15,ADCON1=30. they are correct.
(Internal oscillator is used)

Please help

Cindy
_________________
CC

[rwyoung]

Look at the LST file. Is something occuring after your setup routine to alter the ADC configuration?

Can you post a complete program (main() and the minimum of commands to demonstrate the problem)?

And it is always a good idea to post the version number of the compiler you are using. PCM Programmer and a few others here keep pretty detailed lists of known bugs and in what version they appeared and were fixed.
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!