First post here, and hope I will be able to help this community as much as I can. For now, I have a very serious problem with my Arduino 2560 rev3.
I was trying to build a sketch for a CMOS Color Camera, and I uploaded one containing multiple infinite loops with many data sent over serial (set to 115200bauds). After a few minutes, Arduino COM port became unavailable. I am used to solve these problems, but this time was different. Since this crash, I was unable to upload any sketch, unable to read serial port (but it is detected by my computer).
Symptoms are:
LED "L" undefinilty solid orange directly after power on
Maybe no booting sequence because LED "L" does not blink at all
Button "RESET" does not do anything (LED "L" remains orange even when I push it, after or during powering on)
Connect RESET PIN to GND does not do anything
The upload command output:
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
The command for ship erasing output:
avrdude.exe -p m2560 -C ..\etc\avrdude.conf -c arduino -P com7 -e
avrdude.exe: stk500_getsync(): not in sync: resp=0x00
I have a project to show at the end of the week and the camera was my final step. Please tell me that you have an alternative to force Arduino Mega to boot...
Reload a sketch that does not blast so much data out:
Press & Hold the reset button, start the IDE download. When you see "Compiled xxx bytes of 256K" or similar message, release the reset button. May take a couple of tries to get the timing right.
Already tried that many many times, just to know if I have to try again, is it normal that the LED "L" remains solid orange even if I during I push the reset button?
I think reset button must interrupt all activities, but apparently it does not...
That LED is driven by an OpAmp and the input may be floating. You can try touching the bottom of the board near pin 13 and see if it causes it to turn off.
But it seems to be for the ATMega8 chip only (I have a 2560 rev 3 so it is ATMega16), do you know an easy way to build a ParallelProgrammer for ATMega16 directly on ICSP?
Assuming you are on Windows, does the Mega2560 show up on Device Manager? If so then your ATmega16U2 is probably okay.
The symptoms you are describing indicate that the mega2560 bootloader is gone. So you might just need to put back a bootloader to the mega2560 chip. Yes, it will require some kind of ICSP programmer.
If you have another Arduino it would be easier to use ArduinoISP to burn the bootloader to the mega2560.