The 'Standard' PC serial ports are as follows:
COM1 (address 3F8-3FF) and COM3 (address 3E8-3EF) share IRQ4.
COM2 (address 2F8-2FF) and COM4 (address 2E8-2EF) share IRQ3.
I remember from my DOS days that you can add more serial cards into the
system just as long
as you kept the address's from overlapping, and your software was configured
correctly.
As far as I'm aware the BIOS data area only has place for 4 port addresses:
0000:0400 COM1 address
0000:0402 COM2 address
0000:0404 COM3 address
0000:0406 COM4 address
-----Original Message-----
From: Royce Mitchell III [mailto:royce3@ev1.net]
Sent: Thursday, 17 March 2005 12:04 p.m.
To: ReactOS Development List
Subject: Re: [ros-dev] serial driver bug
Robert Köpferl wrote:
Be aware that it makes a difference wether you have
got a so called
multi serial card or several plain old serial HW. I may be wrong, but
isn't 4 the limit. Due to 'reserved' ports for that kind of HW?
It's a multi-serial card. The 4 limit for plain serial is due to
reserved/limited irq if I understand correctly.
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