ADC and DAC not working

[preynolds101]

I made a post on the Arduino forum regarding an issue that I cannot get the DAC to work (see here).

I also noticed another post that a user is unable to get the ADC to work, which I have also verified (see here).

So, both ADC and DAC seem to be not working at the moment...

[facchinm]

Hi @preynolds101 ,
DAC is not currently supported but it will be very soon; ADCs instead are working fine. Can you provide your sketch so I can test locally?

[preynolds101]

To keep things as simple as possible for testing purposes, I copied the code from the analogRead page of the Arduino reference pages... Sketch attached. When I run it I just get zeros - for testing I'm connecting the 3.3V output to A0.

sketch_jul03a.zip

[facchinm]

You are totally right 😳 This commit is the offending one f0f4a88 ; I'll try to see what is going on and report back soon.
Thanks for the heads-up

[facchinm]

The master branch is fine now; for sake of completeness, I'm writing down what happened.

During mbed-6.0 merge window a couple of commits slipped through (arduino/mbed-os@538552a and arduino/mbed-os@b289d5a in particular).
Without that patches ALTC pins (A0 to A3) were ignored and the call to analogRead() returned 0. All other analog pins were fine.

So, recompiling the mbed library on arduino/mbed-os@6db3edc fixed the issue.

[hpssjellis]

@facchinm @preynolds101 Can we re open this issue briefly. I think if you check you will find that A5 was also missed.

I can run every analogRead from A0 to A6 and they all work except A5, it completely kills the serial monitor.

[hpssjellis]

I have posted on the Arduino Thread here

[ubidefeo]

hi @hpssjellis
I saw your comment in the forum and came here to check it out.
I will test with the Portenta I have, but if you have this issue I doubt J can get a different outcome.
Let's see what @facchinm has to say about it.
Keep you posted.

Also for @facchinm : is analog reference supported? (same Thread in the forum)

[facchinm]

analogReference is not yet supported on the Portenta.
About A5, I pushed 900f717 to fix the crash and regain the functionality, but it needs some investigation since the chosen mux used to be ok.