required clocks running sw_usb_audio in i2s slave mode Topic is solved

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alexjaw
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required clocks running sw_usb_audio in i2s slave mode

Postby alexjaw » Fri Oct 26, 2018 1:17 pm

There are possibilities to configure the usb app to run as i2s slave (some discussion in an earlier thread ). In my application I do want to run the app on xcore-200 chip and use it as an usb-to-i2s bridge. I have a DSP that will act as i2s master.

My question is if I still need to supply an audio clock (either 22.6 or 24.6MHz) to the xmos chip (on the MCA board, the clock pins XS1_PORT_1F and XS1_PORT_1L (tile1))?

In principle, the following clock signals should suffice
- LRCLK from DSP
- BCLK from DSP
- 24MHz main processor clock

AudioHwConfig() needs audio clock, but should be fine without since the app is not responsible for any external configurations in my system (e.g. ADC/DAC), besides eventually telling the DSP about the sample rate from the USB.

In my usb_app (example, see thread) I will also perform sample rate conversion with lib_src. But as far as I can see, src_manager does not use the audio clock frequency.

/AJ
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mon2
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Postby mon2 » Sat Oct 27, 2018 1:44 pm

Hi. Not an audio developer but believe infiniteimprobability references this topic here:

viewtopic.php?f=7&t=6608&p=32680&hilit=i2s+slave#p32680

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