Re: Please help debug - usage of luars232

[Jayanth Acharya <jayachar88@...>]

On Sat, Sep 14, 2013 at 4:11 AM, Sean Conner <sean@conman.org> wrote:

It was thus said that the Great Jayanth Acharya once stated: 

> Presently I am using the library/module "luars232" installed via luarocks.
> I am using this on a Debian Linux machine, on the USB-serial port
> "/dev/ttyUSB0".
>
> I can access this port perfectly well using tools like picocom or minicom,
> i.e. have proper bi-directional communication.
>
> However, when I try this snippet:
>
> [code]
> rs232 = require("luars232")
>
> port_name = "/dev/ttyUSB0"
>
> local e, p = rs232.open(port_name)
> print(e, p)
> [/code]
>
> I get the output:
> 2    nil
>
> Indicating an error in opening the port. One thing that I am pretty sure
> of, is that this isn't a permission issue. Since I have already added my
> userid to the "dialout" group, and use the "picocom" tool similarly. Also,
> I am sure that the port is not in use by any other app/tool at the time of
> running the lua snippet.
>
> However, I am not sure how to debug this further.

  Under Linux, an errno of 2 (and I'm assuming that's what's being return
from rs232.open()) means "No such file or directory" so I would double check
that "/dev/ttyUSB0" does indeed exist (perhaps you need to plug in the
USB-serial device into the computer).

Was testing the serial port periodically using picocom / minicom as well. It was definitely there, and I am positive that there was no mistake in the path-name.