USB Audio - Behringer UCA202 on ARMX6

Can anyone help with getting a USB to audio converter (Behringer UCA202) to work on ARMv7 systems (namely ARMX6). Need a procedure that shows me how to load the required audio software. This is probably Jim Lesurf’s territory. I have looked at his site and tried various things but all to no avail.

Download IsocUSB.zip. Run !IsocPlayer. Double click on suitable wav file – probably a 44100 × 16bit wav file.

Do NOT run !IsocUSB the ARMx6 already includes it.

Running !IsocPlayer and then WAV file gives errors:

USB control failed: Message token * not found and Can’t find block.

It should have given more details than that in the text window that is opened when a file is run. Can you send me the output from that taskwindow and can you plug in the device and run !USBDescriptors from above IsocUSB link above and send that too. The address is on the FTPc page.

Can you also confirm that the device appears on the *usbdevices list.

I have sent you the data requested.

Something very odd is happening here – before running IsocPlayer if I type USBDevices the UCA202 audio device is recognised running on USB channel 9. USBDescriptors also outputs detailed information about all channels up to USB 10. When I run IsocPlayer followed by a WAV computer freezes. If I Alt-break from the freeze and run USBDevices again the report only goes as far as USB channel 6. USBDescriptors confirms this. The USB LED on the UCA202 also goes out indicating the USB channel is down.

Problem caused by the USB port. If I connect the UCA202 to the rear port of the ARMX6 then I can play a WAV correctly, without the device going off-line as it where and freezing the Player program. As Jim Lesurf pointed out all we need now is a programmer to create a multi-tasking desktop player and we could all take advantage of high quality audio available via these USB audio DACs.

My thanks to you Colin and to Jim Lesurf.

As Jim Lesurf pointed out all we need now is a programmer to create a multi-tasking desktop player and we could all take advantage of high quality audio available via these USB audio DACs.

Actually, as Jim in fact said, we need someone to provide OS-level support for the hardware so that both new and existing software can take advantage. I’m pretty sure that something similar is already the subject of a Bounty – so what you actually need is developer with the necessary circumstances, time and interest in the subject to take that Bounty up…

Oh, and people to donate to the bounty, if it’s still short of its target.

Following a discussion on comp.sys.acorn.misc where David Feugey found dr_flac library. I’ve added flac support to a newer version of IsocPlayer which has a desktop frontend.

Unfortunately it will still pause if the desktop is stalled but at least you can now play wav and flac files at native resolution. It has had little testing but it seems ok.

YES!

Tested: works OK with a (recommanded) Fiio Olympus 2 DAC. And not at all with a Behringer UCA-202 (no sound, or not detected, whatever port it’s connected to on my Pi3).

Of course, it’s not (yet) an non interruptable software. But with a dedicated Pi, that’ll be a much better solution than my current DAP, who likes to cut the end of – all – files.

So next, Vorbis?
http://nothings.org/stb_vorbis/

Or MP3?
http://mpg321.sourceforge.net/

MPG321’ decoding part is (was?) just one file. I used it to make the StupidPlayer sequel a long time ago. I remember of my optimisations to support 11-22 kHz output with less CPU power than in 44 kHz mode. The trick was needed for ARM7500 support. Heroic times :)

Anyway, thanks Colin. A very nice Christmas gift.

Could be.that the flac file is 96khz and the Behringer only plays up to 48khz. The player doesn’t play a sample rate the device doesn’t support.

Ah… I’ll check this with other FLAC files.

For Vorbis, Robin Watts did a highly optimized ARM decoder called Tremolo:
http://wss.co.uk/pinknoise/tremolo/

It is based on Tremor, which is said to be portable C.