AVB/TSN Talker-only Configuration

Technical discussions related to any XMOS development kit or reference design. Eg XK-1A, sliceKIT, etc.
akp
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Re: AVB/TSN Talker-only Configuration

Postby akp » Mon Jul 31, 2017 5:42 pm

I am using tdm, not i2s, so it's not exactly comparable. But I changed the buffer_manager_to_tdm to swap buffers after I receive the correct number of audio inputs per viewtopic.php?f=37&t=5850&p=29613
akp
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Postby akp » Wed Aug 02, 2017 8:09 pm

One more note... I am getting gaps in audio with talker only function, but I think only when I use "INPUT_STREAM_DERIVED" media clock, not "LOCAL_CLOCK". I wonder if in "INPUT_STREAM_DERIVED" there needs to be an incoming audio stream to lock to? I also saw some artifacts when running LOCAL_CLOCK so I need to see if that was something with my build. I am thinking to force the clock to LOCAL_CLOCK in talker only mode... perhaps some XMOS types know something about this??

EDIT: I have confirmed that the media clock wordlength doesn't get updated by Mac System Clock unless AVB_NUM_MEDIA_OUTPUTS != 0 due to gptp_media_clock_server() not calling manage_buffer()

Is there any way to get ptp to generate the media clock even when AVB_NUM_MEDIA_OUTPUTS == 0?
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ahogen
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Postby ahogen » Fri Aug 04, 2017 6:14 pm

Thanks for that tip on the audio buffer swap! That should have been more obvious to me, haha.
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akp
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Postby akp » Fri Aug 04, 2017 6:49 pm

I have made enough changes in my code so that AVB_NUM_MEDIA_OUTPUTS can be set to 0. My audio artifacts have gone away, I think (hope) I had some build weirdness caused by not rebuilding all, but not sure.

Have you been able to force the clock to DEVICE_MEDIA_CLOCK_LOCAL_CLOCK? It seems with the descriptors I can't figure a way to disable the DEVICE_MEDIA_CLOCK_INPUT_STREAM_DERIVED as one of the options presented to the peer as I mentioned in viewtopic.php?f=47&t=5986
akp
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Postby akp » Fri Oct 27, 2017 5:35 pm

I have posted up the talker only code on github https://github.com/akp7/lib_tsn

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