SPDIF not seeming to work at 49.152MHz

Discussions about USB Audio on XMOS devices
Jcvc
Active Member
Posts: 40
Joined: Wed May 07, 2025 11:13 pm

SPDIF not seeming to work at 49.152MHz

Post by Jcvc »

Hi,

I was trying to use the SPDIF Tx/Rx with a MCLK of 45.1584/49.152MHz instead of 22.5792/24.576MHz, but when doing this, the SPDIF Tx does not work anymore at 44.1/48kHz, however it still 'works' at the higher frequencies (I'm using the USB audio app on the mc-audio-board). If I have set it to 96kHz, then the actual output rate is 48kHz.

I've tried to halve the frequency on the configuration of the clock block in spdif_tx_port_config() and updated the divide value in spdif_tx(), to ensure data rate consistency, however that did not seem to make any difference.

Do you have any suggestion to what might be the problem? Is this just a matter of updating output_word() in order to adjust for the 'new' ratios? Or am I missing something?

Thank you!