serial port communication

[Grant Edwards]

In article <3c8e6884.10907140 at news.planetis.com>, Hugo wrote:
> Hi,
> 
> I try to have a communication between two computers using the serial
> ports.
> 
> In the interpretor, I just try these instructions :
>>>> from os import *
>>>> fd = open ('/dev/ttyS0', O_RDWR)
>>>> write (fd, "a")
> 1
>>>> read (fd, 1)

> and everything stop : the read() instruction is probably waiting for
> something (I send a character from the other computer but it doesn't
> work) ? 

Unless you've changed the port, it's probably in line-buffered
(cooked) mode, and it's waiting for a newline before it hands
over the line of text to you.


> a stop byte ? or I have use a "timeout" thing ? or the termios
> module ?

That depends on what you want it to do.

> I don't know !

We don't either !

There are a couple serial port libraries around that can make
life easier.  Mine is strictly for Posix (Unix) systems:

 ftp://ftp.visi.com/users/grante/python/PosixSerial.py

There are some others that are cross-platform, and Googling for
"serial" in comp.lang.python should find them.

-- 
Grant Edwards                   grante             Yow!  .. my NOSE is NUMB!
                                  at               
                               visi.com