[comp.os.msdos.misc] msdos and serial ports

jeff@artud2.del.dec.com (Jeff Finkelstein) (03/21/91)

I've been trying to write a terminal emulator for msdos pc's (strictly for fun),
and have run into a problem with the serial ports and trying to drive them at
anything above 1200 baud. Does anyone have any example code or code fragments
that can point me in the right direction?

jlf.
-------------------------------------------------------------------------
Jeff Finkelstein			Digital Equipment Corporation
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jeff@artud2.del.dec.com			my own warped view of reality, etc...

bakke@plains.NoDak.edu (Jeffrey P. Bakke) (03/24/91)

In article <1991Mar21.143019.28770@decuac.dec.com> jeff@artud2.del.dec.com (Jeff Finkelstein) writes:
> I've been trying to write a terminal emulator for msdos pc's (strictly for fun),
> and have run into a problem with the serial ports and trying to drive them at
> anything above 1200 baud. Does anyone have any example code or code fragments
> that can point me in the right direction?
>


Well, I recently had to write a program for work to send and receive files
from an Antique NCR Criterion running VRX (Can you say we still use a card
reader and disc packs).  Anyway, there are a number of fairly simple
example and source code distributions out there at ftp land.  You can
probably easily go to wuarchive.wustl.edu in the /mirrors/msdos/comm or
turbo-c directory.  (I assume you're in C?).  Poke around there and you'll
find various levels of comm packages from simple ASM level interrupt
functions to C level Vt-100 emulator.

At work I finally went with and used an package called Ctask 2.2 (in the
C directory).  Its a multitasking kernel for C programs but it has built
in serial and parallel port routines.  Serial IO up to 38K I believe.
And it is Public Domain, not copyrighted (big plus since I work for a
commericial enterprise).

Anyway, if you need more help tracking any of this down, let me know.


--
Jeffrey P. Bakke       bakke@plains.NoDak.edu
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eric@cinnet.com (Eric Bardes) (03/28/91)

The 'MS-DOS Developers Guild' by the Waite Group contains an excellent
discussion about the serial port.  It has examples, for polled and interrupt
driven serial I/O.  It also has hardware register maps.  Examples are in
Assempler and C.

Eric Bardes