Posted on May 20, 2013 at 19:19
Hello all,
I'm trying to get a demo to work with an isochronous endpoint (audio speaker). My starting point are the Discovery-F4 demos, with USB-FS library upgraded to V3.3.0.
I cannot seem to get the device to work. It enumerates and I can see the AudioControl endpoint. Using libusb-1.0, I can claim the interface, but writing to the endpoint results in a 'device is busy' error message.
I have compared the current source code with that of the demos endlessly, and cannot understand where the problem might be. I took out all DAC/I2S related code, but other than that all the IRQ handlers are identical.
Does anyone have any suggestions for how to debug this? Is there a very simple approach that I can start with (e.g. take out the DMA altogether), and then work incrementally?
Thanks!
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