Serial module

let serial = require("serial");

Methods

setup()

Configure serial port. Should be called before all other methods.

Parameters

• Serial port name ("usart", "lpuart")
• Baudrate
• Optional framing configuration object (e.g. { dataBits: "8", parity: "even", stopBits: "1" }):
  • dataBits: "6", "7", "8", "9"
    • 6 data bits can only be selected when parity is enabled (even or odd)
    • 9 data bits can only be selected when parity is disabled (none)
  • parity: "none", "even", "odd"
  • stopBits: "0.5", "1", "1.5", "2"
    • LPUART only supports whole stop bit lengths (i.e. 1 and 2 but not 0.5 and 1.5)

Example

// Configure LPUART port with baudrate = 115200
serial.setup("lpuart", 115200);

write()

Write data to serial port.

Parameters

One or more arguments of the following types:

• A string
• Single number, each number is interpreted as a byte
• Array of numbers, each number is interpreted as a byte
• ArrayBuffer or DataView

Example

serial.write(0x0a); // Write a single byte 0x0A
serial.write("Hello, world!"); // Write a string
serial.write("Hello, world!", [0x0d, 0x0a]); // Write a string followed by two bytes

read()

Read a fixed number of characters from serial port.

Parameters

• Number of bytes to read
• (optional) Timeout value in ms

Returns

A sting of received characters or undefined if nothing was received before timeout.

Example

serial.read(1); // Read a single byte, without timeout
serial.read(10, 5000); // Read 10 bytes, with 5s timeout

readln()

Read from serial port until line break character.

Parameters

• (optional) Timeout value in ms.

Returns

A sting of received characters or undefined if nothing was received before timeout.

Example

serial.readln(); // Read without timeout
serial.readln(5000); // Read with 5s timeout

readAny()

Read any available amount of data from serial port, can help avoid starving your loop with small reads.

Parameters

• (optional) Timeout value in ms

Returns

A sting of received characters or undefined if nothing was received before timeout.

Example

serial.readAny(); // Read without timeout
serial.readAny(5000); // Read with 5s timeout

readBytes()

Read from serial port until line break character.

Parameters

• Number of bytes to read
• (optional) Timeout value in ms

Returns

ArrayBuffer with received data or undefined if nothing was received before timeout.

Example

serial.readBytes(4); // Read 4 bytes, without timeout
 
// Read one byte from receive buffer with zero timeout, returns UNDEFINED if Rx buffer is empty
serial.readBytes(1, 0);

expect()

Search for a string pattern in received data stream.

Parameters

• Single argument or array of the following types:
  • A string
  • Array of numbers, each number is interpreted as a byte
• (optional) Timeout value in ms

Returns

Index of matched pattern in input patterns list, undefined if nothing was found.

Example

// Wait for root shell prompt with 1s timeout, returns 0 if it was received before timeout, undefined if not
serial.expect("# ", 1000);
 
// Infinitely wait for one of two strings, should return 0 if the first string got matched, 1 if the second one
serial.expect([": not found", "Usage: "]);

end()

Deinitializes serial port, allowing multiple initializations per script run.

Example

serial.end();
// Configure LPUART port with baudrate = 115200
serial.setup("lpuart", 115200);