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Replace 328 with ATMEGA2560

Nadher , 11-17-2020, 06:15 AM
Hello all,

So I developed my own PCB on the same tutorial as 28pin, I replaced ATMEGA238 by ATMEGA2560 and also the same ATMEGA16U2 USB chip.

to download the different bootloaders, I followed the same tutorial as for the 28pin project. How to FLASH the NEW Board but impossible for me to do the first step of preparing 16U2. I don't have an ATAVDRAGON ISP

Then I tried to follow the same steps as the tutorial:
How To FLASH 28Pins Firmware

the download seems to be going fine, but when I try to download the program blinking. I have a timeout error
I can't move forward.

Could you help me, is the first 16U2 preparation step necessary?
robertferanec , 11-20-2020, 08:22 AM
You will need to flash also 16U2 as it is used as USB to Serial adapter between your PC and ATMEGA.

I know, @claudiostazzone was flashing 28Pins recently, maybe he could help? https://designhelp.fedevel.com/forum...gon-programmer
claudiostazzone , 11-21-2020, 02:12 PM
Hello Nadher,
Thanks for posting your message. Thanks to Robert who forwarded this message to me.

I am not so experienced to tell you what will happen using another chip different from the one in the course. I sticked to what Robert explained, in order to ease the job.

I am going to explain some issues I had: they all derive from the fact that in 2017 Atmel was acquired by Microchip. By doing this, all the development software is not available anymore, even the programmer Atmel Dragon is quite impossible to find..

I had some issues with this board, and unfortunately I don't have much time to dedicate to that, at present.

I was able to have one board working out of three, entirely flashed using compatible hardware. I used the Sparkfun pocket AVR programmer with the Microchip/ATMEL suite.
It worked once and then I wasn't able to make it to work again. I then bought the official programmer by Microchip, ATMEL ICE, but unfortunately I wasn't able to correctly flash the board, due to an issue on the USB connector soldering on the 28Pins PCB. That connector is quite impossible to solder by hand, because the pins are covered by the connector shell itself. I have to assemble other two boards, but due to lack of time, the job is pending. I bought an air blower in order to ease the soldering process.

Hope this help in some way... by the way, check the solderings! If you solder the 28Pins by hand, well, some components are very small: ferrite beads, oscillator capacitors, USB connector (critical for the position of the pins), the ATMEGA 16U2 (due to the package)... these I think are the most critical.

Good luck and cheers!!


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