Pi Zero 2 W no I2C comms - What am I doing wrong?

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Hi all. I’m no doubt missing something fundamental here but I can’t see it.

I have a Zero 2 W that I want to connect some Piicodev modules to. As a test I’m using the Piicodev RGB module.

I’ve installed the unified Piicodev library to a venv and enabled I2C comms.

Running ls /dev/i2c-* confirms both I2C channels operating.

I connect one RGB module via the Piicodev adaptor for Pi and see the module has the power LED on. I scan for I2C addresses with i2cdetect -y 1 and get naught.

Swapped out the RGB module for another of the same, and then an ENS160 module. Same result.

Replaced the Adaptor for Pi with a breadboard adaptor, wired it, power on the module, no devices found!

The Zero has pull up resistors on board so I don’t see that as the issue.

I’m stumped.

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I think I may have cooked the I2C GPIO on the Zero when trying to get the SEN55 to work. Refer my other thread re the odd wire colours on the SEN55.

I can’t detect any I2C device I connect to the Zero but I can on the Pi 5.

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@Mark285907, I hate to agree, but if i2cdetect isn’t showing up anything on the Zero, whilst it is on the Pi 5, then the Zero’s GPIO is likely at fault.

If you have a Multimeter, it might be worthwhile checking GPIO 2 & 3 to GND. If your Pi Zero is healthy, you should be getting a solid 3.3V each on both of them.

1 Like
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Alas no. That’s what I get for assuming things.

Thanks Jane.