I2C no acknowledge from address on custom carrier

Hi, I developed a custom carrier board with an I2C0 connection (pins 185 and 187 on the SOM). I’ve successfully flashed the device tree disabling unused pins, however I’m having problems trying to use the I2C.

First, I can’t easily tell which port the I2C corresponds to, which makes debugging it tricky. I tried running the I2CDetect utility on all the I2C ports, they all respond with “no acknowledge from address.” Are there any steps you might recommend to get to the bottom of this?

My first guess is to try reducing the I2C bus speed, but I’m not sure which I2C bus corresponds to I2C0 so I feel like I’m hacking away blindly.

hello jsuffolk,

this failure usually related to power-supply.
please review the device tree property settings, you should assign correct regulator settings to i2c,

I’ll double-check. It’s a direct connection with 2.2K pullup to 3.3V, I think I had matching settings in the PINMUX that I used to generate the DTB.

In a strange twist I noticed I actually do see the correct I2C addresses of the devices on I2C0 in between all the errors. Not sure what to make of it, but perhaps the devices will be able to communicate ok despite the errors. I’ll follow up when I do some further testing.