I am having issues with a PR33-28 board from NCD. It does not show up on the list of i2c addresses but the PR20-10 does show up and a DS1307 clock I had laying around shows up.
I’ve used some of the NCD boards before (not explicitly the PR33-28 however). I was wondering, how have you connected the I2C bus from the Fin to the PR33-28? You may need to check the pull-up resistor header on the PR33-28 (see the image below) if you aren’t using any NCD adapters.
If you could send a picture of how you’ve connected the Fin to the PR33-28, I might be able to help!
Interestingly I was getting away without a shared common ground and with a shared common ground everything works now.
Correction: Our MC7455 is causing ths not to work when it is connected all i2c channels respond.
Glad to know you got it working!