Clock synchronization between Bela and Raspberry Pi

freddyliu

Hey,

I'm considering recording audio using both a Bela board with the audio expander caplet and also a raspberry pi with a hifiberry ADC8x hat. However I'm not sure about how to solve the clock drift issue. From my understanding the clock on the raspberry pi hat must act as a master, so would I be able to set the beagleboard as a slave and wire up the bela board to follow the raspberry pi clock? Or is this not possible.

Thank you very much!

giuliomoro

freddyliu would I be able to set the beagleboard as a slave and wire up the bela board to follow the raspberry pi clock

It is possible but it requires a fair amount of configuration that won't be easy to troubleshoot remotely

freddyliu Solved

Great! What did you do?

freddyliu

Solved

freddyliu

I connected the bit clock and frame clock of the raspberry pi ADC to the Bela. This meant connected the BCLK pin from the pi ADC to pin 9.31 on the bela/beagleboard and the LRCLK pin from the pi to pin 9.29 on bela/beagleboard. Also sharing ground.

Then I had to edit the /root/Bela/core/I2c_Codec.cpp file to set the Bela as a slave. All I had to do was replace any writeRegister(0x08, ...); call to be writeRegister(0x08, 0x00);. After rebuilding the Bela core it should appear as slave.