PIC18F4431 read group ADC

[KB]

Helllo,

I try to read 2 channels (channel 0 and 1) using "group A and B are sampled simultaneously and converted sequentially" mode.
And read the result in a interrupt, but this seems not to be working. The only result i get is the value from one channel depends on what i set in the config "set_adc_channel()".

PIC: PIC18F4431
compiler : 4.057

code:
config adc,

setup_adc(DC_CLOCK_DIV_32|ADC_TAD_MUL_12|ADC_CONT_AB|ADC_WHEN_PPWM|ADC_INT_EVERY_OTHER);
set_adc_channel( 0 );

Interrupt:
#INT_AD
void ADCread ()
{
channel0= read_adc( ADC_READ_ONLY );
channel1 = read_adc( ADC_READ_ONLY );
}

i also try:
void ADCread ()
{
set_adc_channel( 0 );
channel0= read_adc( ADC_READ_ONLY );
set_adc_channel( 0 );
channel1 = read_adc( ADC_READ_ONLY );
}

But that also not working.

What could be the problem?

gr
KB

[Ttelmah]

What you are trying to do, is only partly supported by the CCS functions. Their setup, supports enabling the extra features on these chips, but the read_adc function, only returns the current values in the result registers, as for a normal unbuffered ADC. I'd suggest trying defining ADCON1, and changing the buffer address selection bits, between the reads. So something like:

[Ttelmah]

Note also, the comment in the .h file, about using four parameters to 'set_adc_channnel', for this chip. Looks like you use something like:
set_adc_channel(0,1,NULL,NULL);
Worth some experimenting.

Best Wishes