August 14th, 2005 09:33 AM
*nix port programming in C
this is what I need
I need to be able to do simple port programming of my serial port I have a book that give me the basics for windows but its programs are not portable and I want to use *nix cause it give complete controll over the ports unlike XP. and co.
any way any sites or books would be helpfull
btw I did google for it but the thing either goes over my head or requires me to install a specific compiler and so I dont use them since I am trying to learn by removing that level of abstratction they limit what information I can get
I have already done the basics of both serial and paralell and know a decent amount of it
any help will be much appreciated
(ps: any inline asm code is acceptable for my requirements but could you please use ansi C ..? or is it not possible any way please elt me know)
anything that doesn\'t kill you or your dreams only makes you stronger
August 14th, 2005 11:38 AM
Essentially, in Linux you can access the serial ports /dev/ttyS?
(generic name) like a file, ie you get a filedescriptor with open(),
you write to it with fputc(), you close it with close(). The difficulty
lies in the proper choice of the settings and the communication
Once, I wrote a controller program for a model railway, and
the device specification were not complete - or I did not understand
it properly - it took me ages to avoid the trains crashing all the time
Since you know the basics, have a look at linux.com-HOWTO's[1,2].
But I suggest you to analyse a serial port test program step by step,
which compiles perfectly using
with a default installation of some linux distribution. Go through the
> gcc -o com com.c
source code, and try to understand what they are doing.
You can use the program to send bit's to tty2, or you might try to
"cp /dev/ttyS1 /dev/tty2" in a virtual console and check, whether
the communication works (I have not tested this, but from what I
remember...), or connect two PC's with a null-modem cable.
Notabene: I am not going to discuss the level of abstraction in
the approach I suggested here, nor do I comment on the "control"
over the ports provided by various OS's. Depending on the amount
of time you want to spend into your project, I would recommend
to use the environment you are most familiar with.
If the only tool you have is a hammer, you tend to see every problem as a nail.
(Abraham Maslow, Psychologist, 1908-70)