16F877A problem: "coupled" digital values

[BobK]

Ah-hem, Lupo83,

You probably didn't notice it but we are a PicBasic, forum not a "C" forum.

BobK

[Lupo83]

Yes guys, you are both perfectly right but I DID notice it I was just posting wherever there could be someone familiar with PICs and crosstalk troubles (electronical aspects do not depend on the language you use).
Besides, I was thinking that some basic expert could have also been involved in C matters.
I've already tried to write in C forums but nobody's been helpful yet, so it was despair that drove me here

Of course, I apologize if my post here was unappropriate: in that case, delete it and sorry again

ciao!

[Darrel Taylor]

Hi Lupo,

Good answer. Not a problem.

I think you need some delay between selecting the A/D channel (with ADCON0) and starting the conversion (ADGO = 1;) for sample Aquisition time.

Starting it too soon won't allow the internal Sample and Hold capacitor to fully charge. Which leaves part of the charge from the last channel in it.

HTH,

[Lupo83]

Ciao Darrel,

your answer is the most useful I've read so far, so I thank you very much for that!

I'll test your solution tomorrow morning, since the board/PIC I'm working on are not mine, but have to stay in a laboratory at my university.

Then, I'll let you know.

Best regards.

[mackrackit]

Of course, I apologize if my post here was unappropriate:

I do not think your post was inappropriate, just thought you posted to the wrong forum.
There are a few here that use "C" and I understand needing help.

Tried PIC programming in "C" a few years ago and like you I could not find help. That was one of the reasons I ended up using PIC BASIC.

Good luck.

[Lupo83]

Good morning everybody (here it's 11:40 AM).

Dear Darrel, your suggestion worked fine! You've been the only one to solve the problem, congrats!! I thank you very much for your competence. Hope to get as experienced as you, first or later

[Dave]

Lupo83, If you would have read the data sheet for the PIC it would have told you that there is a minimum time required for the A/D caps to charge before taking a measurement. It's in the Data sheet......

Dave Purola,
N8NTA

[T.Jackson]

I do not think your post was inappropriate, just thought you posted to the wrong forum.
There are a few here that use "C" and I understand needing help.

Tried PIC programming in "C" a few years ago and like you I could not find help. That was one of the reasons I ended up using PIC BASIC.

Good luck.

C / Java is not as intimidating as it first looks - but you will find it difficult to learn from just reading a book. I learned more about Java from 100pgs of lecture material that was straight to the point than I did from reading portions of a 1,000pg book. The practical assignments helped as well. It's clearly a language that needs to be taught formally with a lot of resources for help.

[mackrackit]

C / Java is not as intimidating as it first looks.

About six months ago I purchased two Java books. I am starting to make a little progress. Now my biggest problem is finding time to work on it. The IDEs like NetBeans just made it more confusing. Every one seems to have a different method. Now I am using gedit and compiling from the command line.