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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?

73
John
G4YTJ

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.

John,

Seems like you are close. My notes here aand connecting to the U3 here
The only thing is W10, sometimes reluctant to let you do things..
Should make no difference removing chip. The U3 is powered?

73 Alan G4ZFQ

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?

John, have you got 100K between the reset line pin 1 of the 328 and +5V?? The U3 has pin 1 directly connected to +5V (and I don't think has a ISP header on the U3 board anyway?), and the U3S has provision for R3 (100K) as an option to allow programming.

73, Bob? ZL1RS

Not sure, but perhaps there is an 'internal pull up resistor' activated on pin 1 of the 328 in the QCX rather than use an external component like on the U3S and VFO?

The QCX here programs fine.? If memory serves me correctly, Hans commented that the 328 flash memory (hex) has to be erased before the new hex file can be loaded, rather than just write the new hex file 'over top'.? The programming software used here (eXtreme Burner) does that step automatically, other programming software (like AVRDUDE?) may require that action to be manually done?

73, Bob? ZL1RS

Gents,

Between you you've solved it! Bob was right about the 100k resistor. When I built the kit I put a wire link in instead of the 100k. After fitting R3 I was able to establish comms and connect with the target. I then had issues with verification failure but this was down to me trying to run the target via the USB power. That doesn't work, even with the LCD and Synth boards removed - Thanks Alan. You need to run the target off an external PSU (although the current displayed on a digital meter doesn't seem above 40mA).

As part of my fault finding I tried to roll back to V3.04 which used both hex and eep files. Interestingly the eep file programmed and verified with the U3 powered from the USB, but of course the hex would not verify.

The U3 has't seen any real use, because I haven't had any HF antennas up. That's now been rectified, so it may get an airing. Part of the reason for reprogramming was as a practice for when my QCX gets built, in case there are updates for that.

So now the display shows "Diagnostic mode" on power up. Time to get the manual out and sort it out!

Thanks again for the fast response gents. I really appreciate the ethos of this group with its willingness to share knowledge.

73
John
G4YTJ