What is the device at 0x68 on I2C2 of Google Coral?

Question

I am trying to connect an external RTC (addr 0x68, on Witty Pi 3) to my Google Coral dev board on I2C2 (bus 1). But i2cdetect shows a device at 0x68 even without my external RTC connected. I can't find anything in the docs (SOM or dev board) about a device on this bus. Lady Ada at Adafruit has found it also https://learn.adafruit.com/circuitpython-on-google-coral-linux-blinka?view=all#check-uart-i2c-and-spi-3027971-20 .

Does anyone know about this? Could point me at a doc?

Answer 1

I went to google support: "0x68 is the oscillator for PCIe, I believe it needed for communication with the EdgeTPU, therefore it should not be disabled."

So Witty Pi 3 is a non-starter. I'm lucky there's a Witty Pi 4.