Serial.setTimeout()

Description

Serial.setTimeout() sets the maximum milliseconds to wait for serial data. It defaults to 1000 milliseconds.

Serial.setTimeout() inherits from the Stream utility class.

Syntax

Serial.setTimeout(time)

Parameter Values

  • Serial: serial port object. See the list of available serial ports for each board on the Serial main page.
  • time: timeout duration in milliseconds. Allowed data types: long.

Return Values

  • Nothing

Example Code

  • Compile and upload the below code to Arduino
void setup() { Serial.begin(9600); // opens serial port, sets data rate to 9600 bps Serial.setTimeout(100); // set new value to 100 milliseconds Serial.print("Timeout: "); Serial.println(Serial.getTimeout()); // print the new value } void loop() { // check if data is available if (Serial.available() > 0) { // read the incoming string: String incomingString = Serial.readString(); // prints the received data Serial.print("I received: "); Serial.println(incomingString); } }
  • Type "Arduino" on Serial Monitor and click Send button:
  • COM6
    Send
    Timeout: 100
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  
  • The result on Serial Monitor:
  • COM6
    Send
    Timeout: 100 I received: Arduino
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  
  • Modify the code to change timeout from 100ms to 1ms
void setup() { Serial.begin(9600); // opens serial port, sets data rate to 9600 bps Serial.setTimeout(1); // set new value to 1 milliseconds Serial.print("Timeout: "); Serial.println(Serial.getTimeout()); // print the new value } void loop() { // check if data is available if (Serial.available() > 0) { // read the incoming string: String incomingString = Serial.readString(); // prints the received data Serial.print("I received: "); Serial.println(incomingString); } }
  • Compile and upload the above code to Arduino
  • Type "Arduino" on Serial Monitor and click Send button:
  • COM6
    Send
    Timeout: 100 I received: Arduino Timeout: 1
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  
  • The result on Serial Monitor:
  • COM6
    Send
    Timeout: 100 I received: Arduino Timeout: 1 I received: A I received: r I received: d I received: u I received: i I received: no
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  

When timeout is small, a single string is read multiple time.

※ NOTES AND WARNINGS:

See Also

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Arduino UNO R3
Arduino Starter Kit
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