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From: eddy@duteca (Eddy Olk)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Bridgeboard and serial ports
Message-ID: <999@duteca.UUCP>
Date: 26 Jul 90 00:29:39 GMT
References: <425243@neabbs.UUCP>
Organization: Delft University of Technology, Netherlands
Lines: 56

From article <425243@neabbs.UUCP>, by alexhagn@neabbs.UUCP (ALEXANDER HAGEN):
> Sylvain@speedy.CAM.ORG (Sylvain Tremblay) wrote:
> 
>> I bought the "Dual serial port" for my XT Bridgeboard 4-5 months ago
>> and I wasn't able to make it work.
> 
> Too bad for the *Dual* serial port. The bridgeboard will support only
> COM1 :-(. I have plugged in a par/ser card as well and it works fine.
> 

It is true that the bridgeboard only supports COM1. However, it is possible
to use a second serial port (COM2):

1. COM2 must use IRQ4 instead of IRQ3 (which is used by the bridgeboard itself).
   Most serial cards will have jumpers to change this.
2. Since the BIOS doesn't recognize COM2, it must be manually added by changing
   same date in the BIOS data area. This is done by the next code fragment
   (use debug, your favorite assembler, or email me for the assembled program):

   MOV  AX,0040
   MOV  DS,AX
   MOV  AX,02F8
   MOV  [0002],AX
   MOV  AX,[0010]
   AND  AX,F1FF
   OR   AX,0400
   MOV  [0010],AX
   INT  20


I'm not sure if this 'workaround' works for all communication programs,
especially those using interrupts, but I've no problems using UFO.

>> I heard of a patch that allows using Amy's internal serial port for the
>> Bridgeboard uses.
> 
> Sorry Sylvain, this little program does not exist. Should Commodore ever
> decide to create this program, they will have to supply a new bridgeboard
> custom chip as well, since the CPU ports for the serial port are not
> passed to the Amiga :-(.
> 
> Hope this helps,
> 
> -----------------------------------------------------------------------
>        _     Alexander Hagen   | PRIV MSGS IN DUTCH, GERMAN OR ENGLISH
>      _/_\__  Newtonstraat 20   |
>  ````-o--o-  4532 KH Terneuzen | UUCP alexhagn@neabbs.UUCP
>              The Netherlands   | Fido 2:285/403.2
> ------THE-FIRST-AND-ONLY-UNREGISTERED-AMIGA-BRIDGEBOARD-DEVELOPER------

-- 
______________________________________________________________________
 Eddy Olk                         Delft University of Technology 
 EMAIL: eddy@duteca.tudelft.nl    Department of Electrical Engineering
        EDDY@ET.TUDELFT.NL        Section Computer Architecture
**********************************************************************