Serial (rs232) communication BASH script, port initialisation problem

HogePief · #1 2007-12-28, 08:27 AM CST

At the moment i'm trying to get a shell script (bash 3.2-18.fc8.i386) to communicate with a microcontroller over uart channel 0, /dev/ttyS0

the commands:

Code:

#echo messageToSend > /dev/ttyS0

#cat /dev/ttyS0

work in sending and recieving data, but only when, in this case, minicom (minicom 2.2-5.fc8.i386) is running.
Browsing the internet in wonder of this phenomenon i ran across an example of setting up a serial port in C .

Code:

options.c_cflag |= (CLOCAL | CREAD);

Now looking at man termios, it seems that reading of the port should be set enabled (CREAD in c_cflag).

Is there a way to do this action in bash script (without writing my own application, that gets called in the script), or could there be a different cause of the appearent lack of communication without minicom?

jtang613 · #2 2007-12-28, 08:45 AM CST

Use stty to set the terminal parameters first.

Code:

man stty

HogePief · #3 2007-12-28, 11:55 AM CST

Thanks for pointing me in the right direction.

The solution was:

Code:

stty -F /dev/ttyS0 ispeed 38400 ospeed 38400 -echo