I'm pulling my hair out on this one - and I'm no uC beginner! I've designed in the good old AT90USB162 for the DFU functionality to allow my client to update the firmware via email (which sounded great at the time)
The IC is soldered down perfectly (if I do say so myself) but the USB doesn't do anything at all. Digging in further, using my trusty AVR Dragon programmer connected via ISP, it connects to the device fine (verified with a logic analyser too, SI checked by scope) but atprogram chokes on the device signature reading back "0x1eFF82" rather than the expected "0x1e9482"
I did find a random comment in a dutch language forum:
My AT90USB162's that I bought from Farnell identify with ID: 0x1eff82 instead of 0x1e9482 as stated in the manual ....
What do you think? Still chinese fake?
Atmel support writes ...
Recently, wrong device signature issue has been reported in AT90USB162. It reads device signature as 0x1EFF82 instead of the right device signature 0x1E9482.
Which caused me some concern. I can't see how its a readback/SI/PSU problem as it's all clean, clocked at only 100kHz, and everything looks nice (by eye) and it's a stable result. Are there really fake/counterfeit or just plain faulty parts out there getting into the main distis? I got my supply from Farnell, but even their buyers can make mistakes, so I'm not confident of what I have in front of me. Any thoughts?