Max speed Serial0

With the help of a logic level shifter I connected the Neo to an Arduino Mega. I've created the following sample sketches:

Neo M4:

Code:

void setup() {
  Serial0.begin(250000);
}

void loop() {
  Serial0.println("Hallo");
  delay(500);
  Serial0.println("Wereld");
  delay(500);
}

Arduino Mega:

Code:

void setup() {
  Serial.begin(9600);
  Serial1.begin(250000);
  Serial.println("reading");
}

void loop() {
  int data = Serial1.read();

  if (data > 0) {
    Serial.print((char)data);
  }
}

My question is, is determining the highest serial speed a manner of trail and error, or is there a maximum defined somewhere?

 

Here is a nice topic about this issue. It seems that potentially it can go to 2000000 but the software limits it to 500000 for an original Uno. The Neo has an higher clock speed so could go potentially higher.
You could give it a try on both devices with the program and choose the lowest highest baud rate. The level shifter could also limit the speed.

 

OK and now the link: http://arduino.stackexchange.com/questions/296/how-high-of-a-baud-rate-can-i-go-without-errors

 

I guess I'll settle for good ol' 115200 for now...