Path: utzoo!attcan!telly!lethe!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!dptspd!dleach
From: dleach@dptspd.sat.datapoint.com (David Leach)
Newsgroups: comp.windows.ms
Subject: Re: Dropped characters in Win. Comm programs at 19200 baud
Message-ID: <809@dptspd.sat.datapoint.com>
Date: 21 Dec 90 19:17:45 GMT
References: <1990Dec13.062051.3478@amd.com> <6076@tuminfo1.lan.informatik.tu-muenchen.dbp.de> <1138@kos.rci.dk>
Organization: Datapoint Corporation, San Antonio, TX
Lines: 20

In article <1138@kos.rci.dk> ej@kos.rci.dk (Erik W. Jeppesen) writes:
>
>We are experiencing dropped characters at 19200 baud also outside windows
>and have found that the DOS 3.30 keyboard driver (keyb.com) is the problem. 

I work on a project that will use an async driver that someone else in my
company wrote.  We found that you can lose characters at 19.2 because of
overruns on the comm port.  The principle cause of the overruns was that
other programs were spending too much time in timer interrupts or 
interrupt disabled code which would cause the async code to miss comm 
interrupts becuase they were at a lower priority.  To fix this, an option
was added to the async driver that would cause it to reprogram the PIC to 
make the COMM interrupt the highest priority interrupt in the system.  With
this in, the problem went away.


-- 
David Leach

disclaimer: "I speak for no one . . . just ask my wife!"