Serial Monitor Baud Rate?

Projects Programming
1

Hello, as a Newbie, I didn't work with Serial Monitor before, so I recognize a line of code

Serial.begin(9600);

as setting up the baud rate. Usually it is set to 9600 baud, but would it make any difference if I use another one? Different baud rates between the Arduino and the computer make gibberish start displaying, but I just wanted to know any difference between communication of 9600, 11520, ... .

2

Use what you like, so long as the rate called for in the code matches. The default 9600 is usually fine.

3

Nick_Pyner:
Use what you like, so long as the rate called for in the code matches. The default 9600 is usually fine.

Thank you!

4

pon00009:
[...] but I just wanted to know any difference between communication of 9600, 11520, ... .

Let me explain the difference with examples:

1. Example-1

Serial.begin(9600);
Serial.print("OK");

(1) How much time would be required for the above message ("OK") to appear on the Serial Monitor at Bd = 9600?

(a) Every character travels towards Serial Monitor as a 10-bit data frame as per following format of Fig-1 called Asynchronous Frame:
asyncFrameX.png
Figure-1: Asynchronous data frame

(b) Bd (Baud Rate) refers to number of bits being transmitted/received in 1-sec time. (Simple definition for the UART Post of ATmega328P.)

So, the travel time of 10-bit (one frame) data is: (1/9600)*10 = 1041 us.

(c) Therefore, the message "OK" will take 2*1041 = 2082 us time to reach at the Serial Monitor.

2. Example-2

Serial.begin(115200); //(11520); Edit
Serial.print("OK");

(1) How much time would be required for the above message ("OK") to appear on the Serial Monitor at Bd = 115200?

(2) At Bd = 115200, the message "OK" will take 2*(1/115200)*10 = 174 us to reach at the Serial Monitor.

asyncFrameX.png

1 Like
5

GolamMostafa:
2. Example-2

Serial.begin(11520);

Serial.print("OK");



**(1)** How much time would be required for the above message ("OK") to appear on the Serial Monitor at Bd = 11520?

That's a pretty unusual rate, and may not be supported by the serial monitor.
Try 115200 instead.

6

TheMemberFormerlyKnownAsAWOL:
That's a pretty unusual rate, and may not be supported by the serial monitor.
Try 115200 instead.

I blindly followed @OP's post and did that great blunder.

pon00009:
[...] but I just wanted to know any difference between communication of 9600, 11520, ... .

I have corrected my post.