unleashed-firmware/documentation/js/js_serial.md

js_serial

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

Examples:

// 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

Examples:

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.

Examples:

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.

Examples:

serial.readln(); // Read without timeout
serial.readln(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.

Examples:

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.

Examples:

// 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: "]);