Reprogramming U3

John Pagett G4YTJ

Greetings all,

I have a U3 which I want to update the firmware. I bought a USB-ASP programmer (actually two, I forgot I'd bought the first one!) I've loaded AVRdude and AVRdudess onto my PC (Win 10), sorted out the drivers, soldered a ten way header onto the U3, and plugged it all together.

I've set the programmer as USB-ASP clone (it has the correct VID and PID values) and as far as I can tell the PC can see the programmer. I tried to detect the processor but I get a failure to communicate error. Some communication must occur because the U3 has lost the transmit sequence I had in before (no great loss so I'm not worried about that).

So should I be able to program directly onto the U3 in that manner? Is there anything I need to do to put the U3 in the right mode? I did have the LCD and synth boards disconnected to give me easier access. Would I be better off taking the 348 out and trying to program it on breadboard?


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