I'm working on a prototype of a board using a ATMEGA2580 and trying to use these instructions and code to load the bootloader:
I use the Arduino "Burn Bootloader" and after a couple of minutes I get the error that others have reported using USBTinyISP on the Arduino Mega:
avrdude: verification error, first mismatch at byte 0x3e000 0x0d != 0xff avrdude: verification error; content mismatch
I assume the the bootloader is getting loaded, but when I plug into the onboard USB I do not get a port setup in Windows. I'm guessing the problem is in the RT232RL circuits. I used the same layout for a previous prototype with an ATMega1280 and it worked fine.
The PB7 (D13) led is flashing about every 5 seconds so the CPU seems to be alive. Can anyone confirm that if only the bootloader is loaded that the D13 LED flashes?
I'm using a USBTinyISP clone but I've ordered a genuine AVR programmer to try and I'm going to review the USB circuits and check for shorts, etc. If all that fails I may pull the 2560 and replace it with a 1280.