6-mic array using GPIO clock

Products & Technology ReSpeaker
#1

Hi,



The overview diagram for the 6-mic array shows a jumper which appears to allow the use of the GPIO clock instead of the on-board 24MHz oscillator.



I have an application which requires the DAC clocks on the microphone array to be phase locked with the RPi clock, so I would like to be able to use this feature. Does anyone have any pointers for what to do to use this feature?

#2

Hi there,



here is the schematic related with mclk_en. thanks.







#3

Thanks for that Bill.



I think that the 2520 type oscillator sets its output to high impedance when enable is low, so I should be able to put in the missing link, drive MCLK_EN low, and then drive GCLK from the Pi. My only question is whether a 24MHz clock is feasible to send over the GPIO connector. I know that the AC108 has many possible input clocks. Could you advise on how to program its PLL for a lower frequency clock input?



Colin