I2C Port Expander MCP23017 on Windows IoT


#1

I’m currently trying to get a MCP23017 expander chip working with my DragonBoard410c.
I have it working with a RaspberryPi3 so I know the chip & wiring are good.
Unfortunately when I try to access it as I did with the RPi3 I always get the error “Slave address was not acknowledged”.

AFAIK the chip should be able to work with 1.8V. Is there anything I have to do different with the DragonBoard?


#2

I was able to resolve the issue.

Since the Dragonboard only outputs 1.8V you need to limit your Bus-Speed to 100kHz instead of 400kHz (RPi3).
Then it works just fine.


#3

Great to hear and thanks for following up with a success report! I like those better than failure reports :grin:.


#4

Sure thing. I’ve written a small blog post about my findings & how to avoid some pitfalls: