ATMEGA2560V's bootloader

Hi, i followed this tutorial http://www.gammon.com.au/forum/?id=11635. I have successfully programmed an Arduino Mega2560 using an Arduino Uno. Now i want to program an atmega2560v runnning @ 3.3V, 8Mhz. What i have to do? I have to change something in the "Atmega_Board_Programmer" code or i have to change add a new board in the boards.txt?

I think you'll get away with halving the baud rate in the boards.txt file for the one running at 8 MHz. The bootloader thinks it is running at 16 MHz but since it is running at 8 MHz everything will be at half speed, including the serial speed for downloading.

Thank you Nick Gammon. Then i don't have to change the "Atmega_Programmer_Board" but only the boards.txt adding something like this:

###################################################################
mega2560v.name=Mega Pro 2560V 3.3V
mega2560v.upload.protocol=stk500boot_v2_mega2560.hex
mega2560v.upload.maximum_size=258048
mega2560v.upload.speed=57600                        
mega2560v.build.mcu=atmega2560
mega2560v.build.f_cpu=8000000L
mega2560v.build.core=arduino
###################################################################
Thank you very much

Yes, although wouldn't the protocol be "wiring"? Try it and see anyway.

Hi,
i just finished to solder my own ATMEGA2560V board. I only soldered the ATMEGA2560V, the ICSP pin header, the 8Mhz crystal with 22pF capacitors and the FTDI.
I tried to load the bootloader but i got few errors.
What could bethe reasons?

log.txt (7.94 KB)

You have the "divide by 8" fuse bit set. That can cause issues. You can use the sketch here to change the fuse:

http://www.gammon.com.au/forum/?id=11638

(The wiring is different). You don't need the SD card to change a fuse.

Then try again.

Try changing the LOW fuse to 0xFF.

First, thank you very much for your support.
Thanks to your suggestion I managed to upload the bootloader on the ATMEGA2560v but i can’t upload sketch on it through Arduino IDE(i get timeout error). Maybe this is due i replace the ATmega16U2 with a FTDI chip, I don’t have very clear the roles of the Arduino’s driver.
Perhaps it would be easier upload sketch with your “Atmega_Hex_Uploader” via ICSP but i receive verification errors both with Arduino Mega 2560 and with own board.
Thank you.

LOG2.txt (6.59 KB)

Was this after changing the clock fuse?

If you are running at 8 MHz the standard bootloader won't work because it will be expecting to be running at 16 MHz. Try editing boards.txt to halve the baud rate for the Mega2560 board. You shouldn't be getting verification errors. What sort of wiring are you using?

rents85: First, thank you very much for your support. Thanks to your suggestion I managed to upload the bootloader on the ATMEGA2560v but i can't upload sketch on it through Arduino IDE(i get timeout error). Maybe this is due i replace the ATmega16U2 with a FTDI chip, I don't have very clear the roles of the Arduino's driver. Perhaps it would be easier upload sketch with your "Atmega_Hex_Uploader" via ICSP but i receive verification errors both with Arduino Mega 2560 and with own board. Thank you.

Hi,

Did you manage to upload bootloader and sketch to ATMEGA2560V?