Serial

begin()

Description

Sets the data rate in bits per second (baud) for serial data transmission. For communicating with the computer, use one of these rates: 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600, or 115200. You can, however, specify other rates - for example, to communicate over pins 0 and 1 with a component that requires a particular baud rate.

An optional second argument configures the data, parity, and stop bits. The default is 8 data bits, no parity, one stop bit.

Syntax

Serial.begin(speed)
Serial.begin(speed, config)

Arduino Mega only:
Serial1.begin(speed)
Serial2.begin(speed)
Serial3.begin(speed)
Serial1.begin(speed, config)
Serial2.begin(speed, config)
Serial3.begin(speed, config)

Parameters

speed: in bits per second (baud) - long
config: sets data, parity, and stop bits. Valid values are :

• SERIAL_5N1
• SERIAL_6N1
• SERIAL_7N1
• SERIAL_8N1 (the default)
• SERIAL_5N2
• SERIAL_6N2
• SERIAL_7N2
• SERIAL_8N2
• SERIAL_5E1
• SERIAL_6E1
• SERIAL_7E1
• SERIAL_8E1
• SERIAL_5E2
• SERIAL_6E2
• SERIAL_7E2
• SERIAL_8E2
• SERIAL_5O1
• SERIAL_6O1
• SERIAL_7O1
• SERIAL_8O1
• SERIAL_5O2
• SERIAL_6O2
• SERIAL_7O2
• SERIAL_8O2

Returns

nothing

Example:

void setup ( ) {
    Serial.begin ( 9600 ) ; // opens serial port, sets data rate to 9600 bps
} void loop ( ) { }

Arduino Mega example:

// Arduino Mega using all four of its Serial ports
// (Serial, Serial1, Serial2, Serial3),
// with different baud rates: void setup ( ) {
  Serial.begin ( 9600 ) ;
  Serial1.begin ( 38400 ) ;
  Serial2.begin ( 19200 ) ;
  Serial3.begin ( 4800 ) ;   Serial.println ( "Hello Computer" ) ;
  Serial1.println ( "Hello Serial 1" ) ;
  Serial2.println ( "Hello Serial 2" ) ;
  Serial3.println ( "Hello Serial 3" ) ;
} void loop ( ) { }

Arduino Mega example:

Thanks to Jeff Gray for the mega example

See also

• begin()
• end()
• available()
• read()
• peek()
• flush()
• print()
• println()
• write()
• SerialEvent()
  

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Corrections, suggestions, and new documentation should be posted to the Forum.

The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.