16F88 ADC setup

[wave_man]

Hi all,

I am maybe using the wrong PIC for the job...

I, perhaps wrongly, assumed that I could configure the PIC16F88 for three analog inputs. I want to read AN0, AN1, and AN3, not necessarily at the same time, i.e. useconds are not critical. So, since it appears from the header that I can only configure for one ADC at a time, do I have to call a version of these statements every time I want a different channel?:

[PCM programmer]

The section below is from the 16F88.H file. You can configure
the PIC with one or more analog pins by combining the sANx
constants with bitwise 'OR' symbols. Example:

setup_adc_ports(sAN0 | sAN1 | sAN3);

Then, select the individual channel that you want to do
an A/D conversion on, by using set_adc_channel();
Put in a short delay after changing the channel, before
you do the conversion with a read_adc() statement.
The example in the data sheet shows 20 usec, so just
do this for the delay: delay_us(20);

[wave_man]

Thank you PCMP,

I was not sure you could do this, because the 877A offers explicit combinations in its .h file. Since the 88 .h file only had singles, I assumed there were no other choices.

Regards,

wave_man

[Ttelmah]

The reason for the difference, is in the chip. The 877 (for example), only allows specific combinations, so these are in the .h file. The F88, allows each ADC channel to be selected seperately, so gives the individual bits for these, and allows them to be ored together.

Best Wishes