POSIX Serial Port C Library with Lua Bindings

Uses posix library so it should work with Linux/UNIX environments.

Using this library you'll be able to send and receive data to a device via the serial port to connected devices that have a serial port, have a usb to serial bridge built in or with a usb to serial module. The goal here is to be able to talk with a range or REPLs whether it is forth on an Atmega, Lua on an ESP running nodeMCU or Python on a Raspberry Pi Pico.

See luaserialterm.lua for an example of sending and receiving data.

history

Forked from code found at: biomood/LuaSerial

That was derived from code available at: rtacconi/arduino-serial-posix

Which in turn was derived from code now found at: todbot/arduino-serial

My additions and corrections were derived from (among other places):

A very good description of all options: mbedded ninja blog post

Also the whole thing explained clearly: Serial Programming in POSIX

requirements

Lua 5.1.x

build

Compiled on Debian 12 for Lua5.1 using:

gcc -shared -I /usr/include/lua5.1/ -l:liblua5.1.so.0 -o serial.so -fPIC serial.c

-l:liblua5.1.so.0 will depend on what your shared library is actually named. The same goes for -I to point at the correct headers include path.

usage

Require the library:

local serial = require("serial")

Open a connection to a device

port_handle is the file descriptor
msg is the error message if opening failed

port_handle, msg = serial.open("/dev/ttyUSB0", 115200)
if port_handle==-1 then
  error("Unable to open port - error: "..msg)
end

Write a string

c is number of bytes written
msg is the error message if writing failed

c, msg = serial.write(port_handle, "hello")
if c < 0 then
  error("Unable to write: "..msg)
end

Read up to X number of bytes

c is actual number of bytes read
msg is error message if reading failed, or the string of bytes that were read

c, msg = serial.readbytes(port_handle, x)

Close connection

c, msg = serial.close(port_handle)