CCS811 does not play nice with ArduinoECCX08 and ArduinoMqttClient libraries about ccs811

[maarten-pennings]

Hi, you are using all kinds of boards and libraries that I don't know. I noticed that the ECCX08 also uses i2c. So, I'm wondering if the ECCX08 library sort of resets the i2c library of the ccs811.

Just to check this, you could maybe move the Wire.begin() call to just before ccs811.begin().

[martin-c0des]

@maarten-pennings Thank you for your comment! I realise it's kind of a mess. Surely enough I'm getting "reset failed" when I moved the Wire.begin() call.

ccs811: reset failed
setup: CCS811 begin FAILED
setup: hardware version: 12
setup: bootloader version: 1000
setup: application version: 2000

Do you have any advice on how I can mitigate this issue? Or is it simply an incompatibility between the 2 libraries?

Also - feel free to close this issue as I now understand that it's nothing inherently wrong with your library.

[maarten-pennings]

Interesting to see that you get begin FAILED, but then get sensible results for the three versions, so i2c communication is working.

I think this is repairable but I can't do this without having your board per libraries.

What I suspect is that the ECCX08 library and wire.begin compete for i2c control. Make sure you have only one i2c begin, and make sure both use the same pins. You might need to like inside the ECCX08 library.

[coelner]

I took the first ECCX08 library I found and found this:
https://github.com/arduino-libraries/ArduinoECCX08/blob/8fb63cea34f2ea58e4cdaa7128db20fea39b73a7/src/ECCX08.cpp#L43

Maybe you can use the Sparkfun library, they do it the right way.