Is there a library for working with peripherals (COM-port) in LuaRT?

Alef · 2022-11-11T09:47:24+00:00

How can I organize communication with some peripheral device via a COM port?

steve64

thanks a lot

steve64

Is this issue addressed in LuaRT 1.9.5?

Samir

Yes you can use Pointer to Pointer it should work

steve64

many thanks, I will try that asap

steve64

using external DLLs for serial ports is going to be a nightmare...
I tried various solutions but nothing stable enough.
I would prefer to rely on simpler LuaRT code. So I tried the example code below:

local portName = '\\\\.\\COM4'
local sf = sys.File(portName)
print(sf) --> ok
sf:open('readwrite', 'binary') --> error
sf:write('help\n')
data = sf:read(1)
print(data)
sf:close()

But I got:

File: 000001AD3F2893F0
.../serial_demo2.lua :4: File open failed 'Permission denied'

Is there a reason why the following LuaRT code is not working?
Using a serial terminal the device connected on COM4 is perfectly replying and I did not have any issue from Python as well.

Samir

Yes, because File:open() uses C function fopen() which is generally used to open files rather than ports
To interact with ports on Windows, you'll need to use platform-specific APIs or libraries.

As a side note, LuaRT 2.0.0 will include a serial port module that will support asynchronous operations with Tasks, and will give you fine control over the port settings like baud rate, parity, stop bits, etc.

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