Don't get too excited when printing to serial monitor!!

Development Suggestions for the Arduino Project
1

Hey guys

I spent many hours and even tried re-installing operating systems to fix this probem:

the comport is busy and code does not upload to Mega2560.

but the REAL problem is:

I am using arduino 1.0.5 IDE (not sure if it applies to other versions) and when ever I print THREE EXCLAMATION MARKS to the terminal using Serial.print("!!!"); the code doesn't upload!

It doesn't matter where the exclamation marks are, but if you have more than two in a row you will probably get this problem. Worst part is that the error does not match the problem!

So don't get too excited with your prints!

2

Old problem, !!! would tell the code to go into debug mode or something.
Try uploading more recent bootloader into the 2560.

Got another Arduino?

3

Maybe you have a Chinese clone board, programmed with the very old and buggy bootloader?