Strange behaviour of the Serial.println()

Community General Discussion
1

I'm using the Arduino V 1.6.7 with Mega 2560.
When I'm trying to upload this sketch into the Arduino uploading is failing.
Can somebody test this sketch and find a mistake?

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("!!!");

}

void loop() {
  // put your main code here, to run repeatedly:

}
2

The original bootloader for Mega 2560 has a bug where any sketch with !!! in it will not upload. I recommend removing the !!! or upgrade your bootloader.

You can upgrade your bootloader by using another working Arduino as an ISP programmer, and use the ArduinoISP sketch. Many Mega 2560's are still shipped with the outdated bootloader.

3

dmjlambert:
The original bootloader for Mega 2560 has a bug where any sketch with !!! in it will not upload. I recommend removing the !!! or upgrade your bootloader.

You can upgrade your bootloader by using another working Arduino as an ISP programmer, and use the ArduinoISP sketch. Many Mega 2560's are still shipped with the outdated bootloader.

Wow! Thank You!

4

It's actually part of the boot loader's HELLO conversation with the PC to make sure the boot loader is ready to receive a program so yeah, just a bad choice of 3 characters.