Memos From the Cube

I’m ditching the USB Mass Storage host for now, while I wait for a response from an Atmel engineer. I can’t seem to figure out the problem; the flash disk device is returning a NAK on the bulk IN data endpoint in response to any commands sent on the bulk OUT endpoint. It’s either a power issue, or something more fundamental I’m missing such as a control request I need to issue before the device will start responding.

Today I worked on the Audio Out device, and have finally got somewhere. After a number of bluescreens, and an unimaginable amount of uttered explicatives, I found the source of the problem which was causing the device to bluescreen. After countless revisions of the configuration descriptor for the device (which weren’t entirely fruitless, as I did find and fix a number of issues) I started looking elsewhere. Turns out I managed to completely forget the minor SET INTERFACE control request handler in the library code, which was required by the Audio driver in Windows because the Audio Out project supplies multiple interfaces. Adding that now causes the device to enumerate as a USB Audio device, although I can’t seem to select it as an output device yet in the audio mixer.

If anyone out there uses Linux and can provide me with a formatted, interpreted descriptor dump similar to the one found on this page, I’d like to hear from you. Having such a dump might alert me to clues that I can’t easily see just from studying my code, and Windows lacks such an ability.

In addition, if anyone can enlighten me on what is required to set up an audio hardware device as a mixer output, I’d also appreciate an email. I don’t know how to get from valid USB Audio device, to a mixer output in Windows so that audio can be streamed to it.