Which I2C bus should be used?

I2C2 is a subset of I2C1:

I2C1 can access all registers, including AVS registers.

I2C2 can only access the AVS registers. It's intended to be used if heavy traffic is expected on the general purpose I2C bus (I2C1), to make sure AVS-adaption can be executed without delay.

If only one bus will be used, I2C1 should be chosen to gain global access.  In this case, it is best practice that the I2C lines should be pulled up to VIO or connected to the I2C1 lines.  However, there is no issue if the I2C2 lines are left floating.

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