lilypad works with wrong baudrate

Question

I wrote a simple code on lillypad with fdti module as below:

void setup(){
Serial.begin(57600);
}
void loop(){
 Serial.println("ddd");
 delay(500);
}

but it gives wrong characters at serial port window of arduino ide at 57600 baudrate. But I changed baudrate to 115200 at same window it gives right string as "ddd". Other baudrates do the same thing. What is the solution or where is the problem. I couldnt understand why baudrate shift occurs

Answer 1

The baud rate shift occurs because of a mismatch between the speed your program thinks the chip is running at and the speed the chip is actually running at.

You may also have noticed that delay(500) is too fast and actually lasts as long as delay(250) would.

By the numbers involved it looks like the board is running twice as fast (115200 / 57600 = 2) as your board definition says it is - maybe you're using an 8MHz definition for a 16MHz board, or a 1MHz definition for a 2MHz board, etc.

Make sure you have the right board definition selected in the IDE for your board.