Is it possible to fry an ADC Channel?

[LOLsim]

I've been testing my ADC Channel 0(AN0) and the output is always single digit from the 12bit possible(0 - 4095).

Then, I tested Channel 1(AN1) and it reported the correct voltage.

Did I just fried my ADC Channel 0? Is this possible?

 

[Tahmid]

Hi LOLsim,
On a 12-bit ADC, 4095 is SUPPOSED to be the maximum value. eg. on 8-bit max is 255, on 10-bit max is 1023 and on 12-bit max is 4095.
Your maximum possible ADC value is (2 ^ ADC_Resolution) - 1
And can you explain what happened on AN1? I don't get it.
Tahmid.

 

[LOLsim]

Ya, I know the maximum is 4095.

On AN0, all I get is single digit output(000X) instead of something like 1365.

But on AN1, I can get the actual value(1365).

The settings is correct. I just wanted to ask whether it is possible that I only fried ADC Channel 0 and nothing else.

 

[Tahmid]

Hi,
I don't know about this, but my common sense tells me it's not possible to fry just one channel, as it is actually one ADC module inside with a multiplexer to set the channel to read from.
You sure your settings are right? You set the TRIS bits properly? ANSEL/ADCON0/ADCON1 set properly? Comparator turned off?
I'm assuming you're using PIC.
Tahmid.

 

[Kaleborg]

I believe that it is possible as it happened to me. I managed to fry input 0 and 3 on M16C micro and except these pins the rest of the micro was working correctly(or it seemed to be working correctly). I think that this would depend of the architecture of the micro u are using.

Regards,
Kris

 

[LOLsim]

I did set all my ADCON0,1,2 correctly. I don't think my PIC have the ANSEL bit. Yes, I'm using PIC18F4553. This is more of a question than solving a problem as I am already using other ADC Channel.

 

[FvM]

You are most likely able to selectivly damage any individual pin, causing e.g. "zapping" of the protection diodes
or the output transistors by current spikes of sufficient energy. In some cases, global chip functions may be affect and
result in complete failure, in other cases they aren't.

When treating your development circuits in a rough way (sometimes, you're required to), it happens every day.

 

[kender]

Is it possible to fry an ADC Channel?

Yes, it's possible. I have fried ADC channels with ESD. A few years ago I've done is repeatedly on three PICs over a course of several days (12 ADC channels total). In the next revision of the board I've added series resistors for ESD protection; never fried another ADC channel again.

 

[yousafzai82]

Hi Kender, FvM, Lolsim, Kalborg

I am facing a problem with the selection of microcontroller. I need 2 analog inputs and seven or eight digital inputs. Then i will send the data on GPRS on remote server.

I am confused with frying of one channel for each sensor or i will have to use multiple ICs?
Please provide me with the Schematics of your projects if you can.

Zahoor Ahmad

 

[akvii]

@yousaf zai

pic16f870 will be suitable