I have an odd problem. I just updated a PCB from the 64-pin AT32UC3C2256 to the 100 pin AT32UC3C1256 CPU. Just to get some more I/O pins.
With the old PCB, the USB works without issue. Even the original DFU works.
But, with the new PCB, which has no changes to the USB circuitry, the USB does not work. Neither the working code, nor DFU works.
I verified all of the voltages, etc. quadruple checked the D+, D- and VBUS lines. And, the clocks are all correct.
In fact, tracing the USB code, I receive the 1st GetDescriptor() call, as expected. But, nothing after that.
It seems like the HW is not completing the response ?
The only PCB changes are bringing some pins out t headers for later expansion.
Any ideas ?