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From: rommel@lan.informatik.tu-muenchen.dbp.de (Kai-Uwe Rommel)
Newsgroups: comp.windows.ms
Subject: Disable Windows handling of com port in 386 mode?
Message-ID: <4246@tuminfo1.lan.informatik.tu-muenchen.dbp.de>
Date: 2 Sep 90 14:10:23 GMT
Sender: news@lan.informatik.tu-muenchen.dbp.de
Reply-To: rommel@lan.informatik.tu-muenchen.dbp.de (Kai-Uwe Rommel)
Organization: Inst. fuer Informatik, TU Muenchen, W. Germany
Lines: 30

I have a problem with '386 mode of windows 3.0. For its virtualization
of the PC's resources, Windows handles the hardware interrupts of the
serial ports itself.

Because Windows 3.0 does not support the 16550 chip, I wrote a DOS
device driver which uses its advanced capabilities and creates a new
character device for DOS to access the 16550 port.
This device can be accessed from my Windows app with open(), close() ,
read() and write() without problems in real or standard mode and I can 
transfer data at 19200 baud with very good performance and no data lost.

But under 386 mode, the driver does not receive any hardware interrrupt
(although it hooked up the vector) from the serial port (either COM1 or
COM2) for incoming characters. 

How can I force Windows 3.0 in 386 mode not to handle serial port
interrupts or, more precisely, deliver them to the address where the
vector pointed to before Windows was started (to the DOS device driver)?

The COMx port handling of Windows 3.0 seems to be highly configurable.
But can it be disabled (for one port, that one that is not used by the
mouse)? Or did I oversee something?

Thanks for any ideas,
Kai Uwe Rommel
--
/* Kai Uwe Rommel
 * Munich
 * rommel@lan.informatik.tu-muenchen.dbp.de
 */