Serial.write()

Description

Writes binary data to the serial port. This data is sent as a byte or series of bytes; to send the characters representing the digits of a number use the print() function instead.

Syntax

Use the following function variants to write unmodified data to the serial port:

• Serial.write(val)

• Serial.write(str)

• Serial.write(buf, len)

Parameters

The function admits the following objects and parameters:

• Serial

  : serial port object. See the list of available serial ports for each board on the Serial main page.

• val

  : a value to send as a single byte.

• str

  : a string to send as a series of bytes.

• buf

  : an array to send as a series of bytes.

• len

  : the number of bytes to be sent from the array.

Returns

The function returns the number of bytes written, though reading that number is optional. Data type:

size_t

Example Code

The following code shows how to use

Serial.write()

1void setup() {
2  Serial.begin(9600);
3}
4
5void loop() {
6  Serial.write(45); // send a byte with the value 45
7
8  int bytesSent = Serial.write("hello");  //send the string "hello" and return the length of the string.
9}

Notes and Warnings

Serial transmission is asynchronous. If there is enough empty space in the transmit buffer,

Serial.write()

Serial.write()

Serial.write()