dead arduino, new atmega328p w/ bootloader + loopback test ok => nothing

I have a dead arduino. It died in an accidental short circuit (was measuring 42v output pin of a stepper motor driver and accidentally touched the pin just by it's side, a control pin connected directly to arduino, which killed both, the controller and arduino) I am not sure which pin it was connected on arduino, but it was between 2-9 range.

After the accident I tried to turn the arduino on again, but it would only get hot and do nothing, figured the atmega328p-pu died, bought a new one (just the ic). You have to understand how hard is to find this kind of stuff in Brazil, I've got my arduino from the US, but now I don't have much time to wait for another one to come by mail (international mail to Brazil takes 1-2 months to arrive, customs bullshit).

I flashed the arduino using a DAPA cable I've made following the tutorial, quite a PITA to get it working, but I figured it out. The avrdude communicates with the atmega328p-pu successfully, but, as I am dumb, I changed the fuses before uploading the bootloader and I couldn't communicate to it anymore because I've set the fuse to use an external clock (genious, don't). I had to remove the crystal oscillator from my uno board and connect it to the breadboard and then was able to upload the bootloader (which was successful) to later put the crystal back on the board. I have to emphasize that I tried uploading the bootloader a couple of times, using the avrdude command line first and the arduino ide later. Both flashed successful.

The problem is that when I put the arduino back on the board (and the crystal too). It won't do anything, it won't communicate with the computer, it won't reset, I can't upload programs to it.

I have read about the loopback test and did it without my atmega328p-pu on the board, the serial port monitor shows everything I type back, which was supposed to be good news. The bad news is that I don't know where the problem is.

When I remove the atmega328p-pu from the board the led on pin 13 still works when connect to usb, but it won't turn of, even when I press the reset button, in fact, nothing happens when I press the reset button, even with the atmega328p-pu on the board. No led blinks. Absolutely nothing happens.

When I try to upload a code to the arduino, the rx led blinks 3 times, but the tx led doesn't blink at all. I have read about some guy with a similar problem, but there was no solution on this other thread.

The IDE then reports:

avrdude: stk500_getsync(): not in sync: resp=0x00

Another clue that might lead to the problem is: when I touch the pins around pin 13 under the board, the led dims, like my finger is conducting energy between the pin and the ground, leaving low current left to the pin.(sorry, I am no electronics expert, just a curious geek that studies CS and is in desperate need of help)

Any clues on how to fix the problem? Any help is very welcome.

Another question: can I use the DAPA cable to upload code compiled in the arduino IDE to the atmega328p-pu and use it as a standalone arduino without communication to the PC? This would help me to keep going with my projects if I have to buy another board.

I sincerely thank you all in advance for your time spent helping me,

Igor

You can burn sketches via the ICSP, which I presume is the same thing as DAPA (MOSI, MISO, etc.?).
When you upload via ICSP then there’s no bootloader, that much more space left in memory.

http://www.gammon.com.au/forum/?id=11637


By “the board” do you mean a Uno or Duemilanove or similar? Those have an interface IC (between the USB and the ATmega comm pins 2, 3), but it’s bypassed when programming via ICSP.


So, if ATmega pins 2 or 3 got touched, then the USB interface IC (the FTDI, or whatever the Uno uses for that) got wasted, too. Which would explain being able to bootload it, which requires ICSP or another functioning Arduino, but failing to Upload via serial/usb.

By "the board" do you mean a Uno or Duemilanove or similar?

Uno R3, sorry.

So, if ATmega pins 2 or 3 got touched, then the USB interface IC (the FTDI, or whatever the Uno uses for that) got wasted, too. Which would explain being able to bootload it, which requires ICSP or another functioning Arduino, but failing to Upload via serial/usb.

Not the atmega pins 2 or 3, the Arduino Uno R3 pins 2-9 were used, the pins are different from atmega to arduino... And I already got a new atmega328p-pu IC (which I uploaded the bootloader to), the other is dead, gets hot on power on.

No telling what havoc that 42V stuff will play.

But, still, try pursuing the ICSP means outlined in the Gammon link.

Bump!

Is there any way to revive my arduino?

It's difficult to know what else is damaged, perhaps the USB chip, or part of it. You could try getting a FTDI cable, connecting it up to Tx/Rx etc. (bypassing the USB interface) and seeing if you can program it that way.

If you can program it via ICSP, then you could upload a sketch that exercises the serial comms (eg. read from Serial, echo back) and burn that onto the chip. Then try with the serial monitor to see if it works. If not, somewhere in the path from your 328 chip, to the USB, something is damaged. Maybe it can be fixed. If it is the USB chip that will be virtually impossible to remove and replace without specialist tools.

If it can be used, if you program it via ICSP, then you could use that board for situations where you don't need to program it that often (eg. in the field).