Serial

The @std/net/serial package provides serial port access.

import serial from "@std/net/serial"

const port = serial.Port("/dev/ttyUSB0", 9600)
defer port.close()

port.write("hello\r")

const out = port.read(2000)

println(out)

Import

import serial from "@std/net/serial"

Exports

Name	Kind	Description
Port	struct	Serial port connection type.

serial.Port

Opens a serial port.

Arguments:

Name	Type	Default	Description
device	string	none	Serial device path.
baud	int	9600	Baud rate.

Returns: Port

import serial from "@std/net/serial"

const port = serial.Port("/dev/ttyUSB0", 9600)
defer port.close()

Use the default baud rate:

const port = serial.Port("/dev/ttyUSB0")
defer port.close()

port.write

Writes text data to the serial port.

Arguments:

Name	Type	Description
data	string	Data to send.

Returns: void

port.write("hello from writer\r")

port.read

Reads data from the serial port.

Arguments:

Name	Type	Description
timeoutMs	int	Read timeout in milliseconds.

Returns: string

const out = port.read(2000)

if out != "" {
    println("Reader got:", out)
}

Internally, read uses a read timeout and reads up to a buffer of data.

port.close

Closes the serial port.

Returns: void

port.close()

Prefer defer after opening a port.

const port = serial.Port("/dev/ttyUSB0", 9600)
defer port.close()

Reader Example

import serial from "@std/net/serial"

const reader = serial.Port("/dev/pts/4", 9600)
defer reader.close()

while true {
    const out = reader.read(2000)

    if out != "" {
        println("Reader got:", out)
    }

    sleep(1000)
}

Writer Example

import serial from "@std/net/serial"

const writer = serial.Port("/dev/pts/1", 9600)
defer writer.close()

while true {
    writer.write("hello from writer\r")
    println("Writer sent: hello from writer")
    sleep(1000)
}

Function Syntax Note

Use -> only when describing a function value type.

let reader: fn(int) -> string

When writing a function implementation, put the return type after the parameter list.

fn readOnce(timeoutMs: int) string {
    return conn.read(timeoutMs)
}

For a function that returns nothing, use void.

fn closeConn() void {
    conn.close()
}