The USB drivers for the Empeg are actually quite simple. It's all in the kernel tarball on the Empeg site. The driver implements it as set of character devices and allows you to access the endpoints directly. We don't have full control over endpoint 0 however but we shouldn't need to anyway.

Do you know of any low cost microcontrollers with a built in USB master capability however? If not then we'd need to implement the USB protocol directly which to be honest, will be a pain.

Technically we'd need a device with two USB master interfaces or add a USB hub chip. If the microcontrollers aren't too expensive, we could just connect two of them back to back.

- Trevor