save my arduino mega 1280!

Development Tools IDE 1.x
1

I tried to interface my arduino mega 1280 with external hardware via serial. The mistake I made was to connect both serial cables to pin 0 and 1 of my arduino which are also used for communication with the computer. I guess it made a short circuit as the arduino doesn't answer to the computer. Actually the led connected to pin 13 doesn't light up when I reset the arduino and the communication leds don't light up too. But the ftdi chip does work and the power led does light up. Of course the arduino ide doesn't manage to program the arduino.

Is my arduino dead? Or only the serial pins 0 and 1 are dead? If so is it possible to burn a new bootloader that will use another arduino serial port to be programmed by the PC?

Thanks in advance and sorry for my bad english

2

Soranne:
I tried to interface my arduino mega 1280 with external hardware via serial. The mistake I made was to connect both serial cables to pin 0 and 1 of my arduino which are also used for communication with the computer. I guess it made a short circuit as the arduino doesn't answer to the computer. Actually the led connected to pin 13 doesn't light up when I reset the arduino and the communication leds don't light up too. But the ftdi chip does work and the power led does light up. Of course the arduino ide doesn't manage to program the arduino.

If the ftdi chip does indeed still work (did you run the loop-back test, that is the only way you can tell if the ftdi chip is fully functional, not just that the PC sees a USB connection when plugged in.) then there is a possiblity you have damaged pin 0 and/or pin 1 on the 1280 chip. If you have another arduino board you could always program your board by running the arduino as ISP sketch and use the new 'upload using programmer' feature that the latest IDE.
Are you sure the external serial device you tried to wire up was using TTL voltage serial data and not RS232 voltage serial data? That could damage arduino pins.
Lefty

Is my arduino dead? Or only the serial pins 0 and 1 are dead? If so is it possible to burn a new bootloader that will use another arduino serial port to be programmed by the PC?

Thanks in advance and sorry for my bad english

3

Thank you for your answer.

Yes the loopback test does work.
Where can I find a modified bootloader for this case? I don't know a lot about AVR's assembler :s

And yes the hardware had ttl level (it was a minitel)