WIFI module causes PMOD TC1 to not work properly

[Marty]

I have two PMOD TC1 which work fine when communication to PC is via USB, when I switch to WIFI communication the readings are not correct (lower by 2 or 5 degrees F depending on PMOD position on PMOD shield).   The 3.3 volt supply level is still the same with WIFI on, the problem (my guess)  is WIFI TX portion of WF32 gets a little coupled into PMOD TC1.  VERY frustrating.

The PMOD shield with the default  direct  SPI connection is above the WIFI unit on WF32 and is effected the most,  Pmod connection next to  connection right next to it for second.  Also WIFI uses SPI which may or may not add to the problem.

 

Marty

 

[jpeyron]

Hi @Marty,

Are you still having issues with your Pmod TC1?

thank you,

Jon

 

 

 

[Marty]

Thanks, JP.

 

For now, I'm going to avoid WIFI and Pmod TC1 on the WF32.   If someone can bench it back in your lab, below is what to do to see issue.

This one should be easy.

1) Install WIFI firmware on WF32 with invalid  settings so it won't connect to a network.  Make sure WIFI unit is on (not connected to network, just on)

2) Use USB to do all communications.

3) Install two Pmod TC1 in pmod shields slots above WIFI module. I think its JC and JD.

4) Tape ends, but don't put tape on bead, of thermocouple  (tape just below bead) so beads are very close together ( less than 1 mm) and stick them in a WF32 box and stick that box in a desk drawer.

5) Run a continuous acquistion loop and plot both temperatures against time.

6) Two thing can happen, SPI read error, or temperatures off 2-5 degrees F.

 

Prior to doing wifi firmware install, you can run the loop and see what temperature difference between two thermocouple for a reference.

 

Curious what you get .I've also noticed if seebek ICs is are at different temperatures then temperature readings will be affected.  This even happened when WIFI module is OFF (reload USB firmware to turn off wifi unit)

thanks,

Marty