I sent David a private message re: this topic, but I don't think I sent the
same info to the list (sorry if I already did).

It is  a _very_ bad idea to directly access the UART in Win32. For starters,
it won't work at all for NT/2000. Also, we are starting to see more and more
environments where COM ports are implemented without a conventional UART
being there at all (USB, for example).

You really should bite the bullet and learn how to do what you need with the
Windows API. I've implemented quite a few things using the API, and while it
is a pain, it can (almost?) always get the job done, if you are creating
enough.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)


----- Original Message -----
From: John Pfaff <pfaff@WRITEME.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, March 30, 2001 8:40 AM
Subject: Re: [OT]: Com port base address


> Under DOS and Windows the addresses are stored in the BIOS data area as
> follows:
>
> 0040:0000 COM1 Port Address
> 0040:0002 COM2 Port Address
> 0040:0004 COM3 Port Address
> 0040:0006 COM4 Port Address
> 0040:0008 LPT1 Port Address
> 0040:000A LPT2 Port Address
> 0040:000C LPT3 Port Address
>
> - John
>
> ----- Original Message -----
> From: "David Duffy" <piclist@AUDIOVISUALDEVICES.COM.AU>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Thursday, March 29, 2001 6:05 PM
> Subject: Re: [OT]: Com port base address
>
>
> > David Stubbs wrote:
> > >Hey,
> > >
> > >Does anyone know of a way I can find out the base address of the
> different
> > >com ports in my program I am making under Windows. Thank for your help.
> >
> > com1            Hex 3F8
> > com2            Hex 2F8
> > com3            Hex 3E8 (?)
> > com4            Hex 2E8 (?)
> > Unlike LPT ports, com ports have fixed base addresses.
> > Regards...
> >
> > --
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> >
> >
>
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>

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