USB Audio 2.0 MC with no inputs flips Thesycon?

[radaudio]

Hi,

I have just received our first prototype board based on XS1-L2 device and USB Audio 2.0 MC reference design.

Hardware seems to be OK - I can can program the device, get good clock signals and even see it in Thesycon driver panel.

My first step is to build application without inputs clocked from external audio clock source connected to XMOS pin. This is where my first issue starts...

When the project is compiled without inputs (NUM_USB_CHAN_IN == 0, I2S_CHANS_ADC == 0) thesycon driver detects the device, shows it has a valid clock (with clock frequency) but the audio device is not detected by windows. TUSBAudio SPY tool shows the device but with a very limited set of data - just one page with "Device 0".

When I compile the project with inputs specified (NUM_USB_CHAN_IN > 0 and I2S_CHANS_ADC > 0) the Thesycon driver detects the device as a valid audio device and I can assign it as a default output from windows. Thesycon SPY tool gives a lot of informations (number of outpus, inputs, windows name etc...). I don't want to mess too much with the application at this stage so I have commented out the clockGen() which I think makes the driver corrupted - clocks show as invalid and I cannot stream audio to the xmos chip.

Question now - is there a way to make the driver work with the MC application with no inputs defined?

Thanks in advance for any help. This thing is killing me....

Cheers,

gx

[Ross]

When the project is compiled without inputs (NUM_USB_CHAN_IN == 0, I2S_CHANS_ADC == 0)

This should be all that is required with the latest codebase, however, on older codebases I seem to remember an INPUT define also.

[radaudio]

Hi,

Sorry for a late reply. It turned out the problem was hardware related - the intermittent problem with usb audio driver came from a noise in the main clock system. Once we've fixed the problem the audio driver works quite reliably.

Cheers,

greg