Can't use second I2C bus on seed

As far as I understand, yes. I2C_1 and I2C_4 are the two peripherals that are exposed on Daisy Seed. They also are both available on pins D11/D12 and D13/D14 if I understand correctly; i.e., you can initialize either peripheral on either sets of SCL/SDA pins. That said, I’m having some trouble myself getting IC_4 working, as explained in this post:

So, try it and see if you have better luck than I’m having. :slight_smile: