Need suggestion about adc

[misel0019]

Hi, now I'm working with 18f4550.
I want to read 3 analog voltages from 3 different source, reference to 5 volt.

I'm trying to connect

RA0 with sensing point1 with 100k to ground
RA1 with sensing point2 with 100k to ground
RA3 with sensing point3 with 100k to ground

Usually I do that in ATMEL IC

and I command it showing here

set adc channel 1 ->start conversion->usedelay->read
set adc channel 2 ->start conversion->usedelay->read
set adc channel 3 ->start conversion->usedelay->read


I'm usually familiar with Atmel IC.
I did it that way.

But now in PIC I see that there's a problem with that procedure.

I found clamsy type data.
If anyone have suggestion on reading multiple analog voltage from different pin please suggect me to do that in your right way.

Again thanking you
Misel0019

[misel0019]

Hurrah I have done it on Proteus, now I'm working on real board.

And hoping everything will be as I expected.
Regards
Misel

[SherpaDoug]

I'm glad things seem to be working for you. But I should point out that you need a delay between setting the A/D channel and starting the A/D conversion. The PIC needs time for the multiplexer to charge the capacitance of the A/D input. You will have to read the data sheet to see how much time, but it is usually about 20 or 30us. If the time is too short your readings on one channel will be influenced by the other channels.
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