Issue with UNO Mini le bootloader

Using Arduino IDE 1.x
1

Hi,

After purchasing one of the limited edition boards a few months ago, I finally decided to take it out the case and test a bit of code on it. Unfortunately it did not appear to be recognised by the IDE. When I looked on the device manager I did not see any com port devices listed, however I could see a device that was listed as an Atmel Atmega 16u2. After a bit of initial digging I found that this relates to the chip that acts as a serial converter for the main Atmega chip.https://support.arduino.cc/hc/en-us/articles/4410804625682-Set-a-board-to-DFU-mode. following these instructions I flashed what I believed to be the right uno hex file to the board. Now it registers under the IDE as Uno board, although perhaps there is something that should be changed so that it registers as an UNO Mini. Now I try to download the test sketch but that fails, so I gather that the bootloader must also be absent. The connections where a bit tight given the smaller form factor but I just about managed to get all the connections necessary in place. The Uno hex file for the bootloader was flashed onto the main Atmega using avr studio, which suggest that it had flashed the chip successfully. Admittedly I am not sure if this was the right one as the appears to be more than one bootloader hex file for the 328 chip. When I try to load the blink sketch, it hangs for a while before outputting:

An error occurred while uploading the sketch
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x4c
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x4c

Any guidance would much appreciated, If I have left any details out let me know and will provide it.

Cheers

Ryzer

2

Hi @ryzer

It would be the USB VID/PID pair which is coded into the ATmega16U2 firmware. This is how the Arduino IDE identifies the board. The Uno Mini has a different PID than the Uno.

This difference is essentially only cosmetic in this case since the two board definitions and firmwares are otherwise functionally identical, so it won't cause you any problems so long as you don't mind the identification discrepancy.

It is this one:

https://github.com/arduino/ArduinoCore-avr/blob/master/bootloaders/optiboot/optiboot_atmega328.hex

Is that the file you used?

3

hey @in0

Thanks for your reply.

Ok that is perfectly.

Yes I did use that hex file. Out of interest, I read the settings off of my UNO board and found that one of the fuse bits differed slightly to what I initially found while searching around. This was my original reference
https://www.re-innovation.co.uk/docs/avr-dragon-to-program-arduino-bootloader/
The High fuse on my UNO registered as 0xD6 where as this article suggested a value of 0xDE which may have contributed to my problems.
After directly copping the UNO's hex file onto the Mini LE the D13 led now blinks. It still fails to programmed with the ide but there is a little bit more activity going on. before only the rx led would flash but now the tx blinks a bit as well. Now the error code is slightly different.

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x60
4

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