Can't Program Mega 1280 because of Serial Traffic.

I have an Arduino Mega 1280 which I was using to debug some sensors. Now I can't program the mega to run any other code. I'm guessing the all the traffic is causing the malfunction. I have an Arduino Duemilanove and I was trying to use it to reprogram the Mega using ArduinoISP but to no avail.

When trying to program the Arduino Mega with Serial USB cable, Arduino IDE hangs on uploading and the RX and TX lights blink a few times (3 I think) and then the TX light is constantly on.

When I use ArduinoISP, the IDE gives me either:
avrdude: stk500_getsync(): not in sync: resp=0x15 or
avrdude: stk500_getsync(): not in sync: resp=0x00

Any suggestions?

Try holding the Reset button, unplugging and re-plugginf the USB cable, clicking the Upload button and releasing Reset when you see the RX light blink.

I tried it, but the processor begins the sketch too fast.

ChowMix12:
I tried it, but the processor begins the sketch too fast.

If the processor begins the sketch before you release the Reset button then something is very wrong. :frowning:

The sketch doesn't run when I'm pressing the reset button. But as soon as is let go, the program runs almost immediately..

ChowMix12:
The sketch doesn't run when I'm pressing the reset button. But as soon as is let go, the program runs almost immediately..

That is why you wait until the upload begins before releasing the Reset.

Unplugging and re-plugging the USB cable clears the USB buffers.

I did wait until the leds blink a few times. I also tried releasing the reset button when the IDE tells me the sketch size.

The same problem happened to me.
When I tried to load the program the IDE gives 'Uploading...' forever and the TX Light was constantly on.
What happend was that my APC220 was connected to the Mega and I needed disconect the cables of '5V' , 'RX' and 'TX' pins.
This resolved my problem, I could uploading the code to de Mega normally after that.

[]'s