Serial Device communication, occational freeze on one machine, no freeze on the other

Serial Device communication, occational freeze on one machine, no freeze on the other

Post by jlibste » Sat, 15 Nov 2003 15:09:54

Folks, I've got a real problem I've been banging my head on for a few
hours: Helped a friend get together some computers for a hearing aid
store: Configuration is: AMD 1.2 Gig Athlon CPU, Asus A7V8X-X
Motherboard, Samsung RAM (256 MB), with basic ATI Xpert 2000 video
card, AOpen 16X DVD Rom drive, Windows 2000 Pro. 2nd machine: Fujitsu
Intel P4 Mobile(1.2 Gig) Laptop with Windows 2000 Pro. They both use
software which
interacts with a hearing aid programming device through a serial port
on COM 1.

Problem: Occationally, when using this serial device, the application
would freeze, Windows 2000 Application log gives a serial error
message, and no device can detect the serial communications port
unless you disable
the communications port in the hardware manager, and then reenable it.
Then everything works again. Now, this only happens on the workstation
with the A7V8X-X board. The fujitsu laptop has NO problem at all. Now
get this: Looking at the settings the programs using this device
generally have the default rate at 19200 bps, so I adjust the
communications port to the same speed. Now, things seem to be much
more stable until...we do fine tuning: two of the applications
actually allow you to set the bps rather than accepting the 19200
default that most of the apps had. On ONE particular application,
anytime I changed the bps settings or even leave them the same and hit
the magic "ok" button, it CONSISTANTLY makes the serial communications
port unresponsive as before, freezes the app (not the os, I can still
kill tasks), and again requires the disable/reenable proceedure to
revive it. Some response sent from the device to the workstation (if
the serial device is unplugged its okay), received by the workstation
seems to make the communications port on the A7V8X-X board just freeze

Now, the Fujitsu laptop (which has a Intel based board by the way),
doesn't have this issue given the same circumstances (incluing the
magic "serial killer" app): it runs perfectly, no hitches, even with
the default transmission speed left at 9200. Can anybody tell me why
this might be happening and why one machine has no difficulity, and
even better, what a solution is short of trying out a bunch of other
motherboards (which I'm not convinced is the answer yet, but in light
of the perfectly functioning laptop, I just don't know). BIOS settings
on both
laptop and A7V8X-X motherboard workstation are left at default
(Address 03F8 IRQ 4) for
serial port settings. The Asus board has the integrated modem option
(which it doesn't have in any event) disabled as well as the game
port. Thanks a million guys.

Jonah A. Libster