EMC2101 breakout not working with M0 / M4 boards

[uberpenguin]

Using this breakout:
Adafruit EMC2101 I2C PC Fan Controller and Temperature Sensor, PRODUCT ID: 4808

Running this code:
https://github.com/adafruit/Adafruit_EM ... 1_test.ino

Fails to run on these boards:
Adafruit Feather M4 Express, PRODUCT ID: 3857
Adafruit ItsyBitsy M4 Express, PRODUCT ID: 3800
Adafruit QT Py - SAMD21 Dev Board with STEMMA QT, PRODUCT ID: 4600

Serial output stops at: "Adafruit EMC2101 test"

Above EMC2101 breakout, with above referenced code, runs as expected on
Adafruit Feather HUZZAH with ESP8266, PRODUCT ID: 2821

Development enviroment:
Platformio / Visual Studio Code
Version: 1.52.1
Commit: ea3859d4ba2f3e577a159bc91e3074c5d85c0523
Date: 2020-12-16T16:32:10.090Z
Electron: 9.3.5
Chrome: 83.0.4103.122
Node.js: 12.14.1
V8: 8.3.110.13-electron.0
OS: Linux x64 5.4.89-1-MANJARO

Using arduino framework & following libs and board available through Platformio:
lib: Adafruit EMC2101 by Adafruit, version 1.0.3
boards: Atmel SAM, version 5.1.1, Espressif 8266, version 2.6.2

Also, the above M4 / M0 boards work fine with / without Adafruit TCA9548A I2C mux breakout & INA260 power monitor breakout.

Problem with the EMC2101 lib on ARM? Or, more likely, what am I doing wrong?

Thank you much for any help.

[mikeysklar]

Hmm, sounds like this is limited to our 3v3 boards. If you followed our wiring diagram for the Metro that has the 5v line being used, but I think you will actually want a 3v going into the EMC2101 so you don't mess up the i2c communication. I think the red wire coming off the Metro 5v in the example below would cause the hang you are seeing on the M0 and M4 boards.

Screen Shot 2021-01-22 at 11.16.59 AM.png (642.89 KiB) Viewed 230 times

[adafruit2]

this demo is a feather m4 so it def works with samd51 series
https://www.adafruit.com/product/4808
probably a wiring issue as mikey says, power it from 3V logic!

[uberpenguin]

Thanks for the feedback! I actually used one edge bus on the breadboard for my V+, and it was tied to 3.3V. I was not using 5V for anything in the setup. I also had an INA260 on the I2C bus with the EMC2101, powered from the same V+ bus and it worked great. I may revisit it, as I have no doubt it should be working with at least the M4 I tested with, based on the demo you linked above.

Problem was ultimately solved by removing the EMC2101 from the design. Once I discovered that it only had 16 steps (6.25%) at my desired 25KHz PWM frequency I refactored the HW design. Settled on a Teensy 3.5. I now have 8 channels of 25KHz PWM with 0.10% duty cycle resolution and 8 channels of tach feedback with a lot of pins left and some real simple, clean code.

Thanks again for the help and with the great products and support!

[SeiteBroken]

Hey,
I'm having the same issue. I can run the EMC2101 circuit python script on my SAMD21 Dev Board with STEMMA QT and it is working fine.
But the arduino script is not working. I only get the same output:

Serial output stops at: "Adafruit EMC2101 test"

Thank you much for any help.

[mikeysklar]

@SeiteBroken,

Is the Arduino script being run on the same SAMD21 dev board that you had run the CircuitPython code on? I'm trying to rule out soldering / wiring issues and this being a pure software problem.

[SeiteBroken]

I use the STEMMA QT Connection. An yes it is the same board. So I think it is a software problem