[Coco] a not very important Drivewire question

[Kip Koon]

Hi Robert!
If possible, I'd like to see the source code for this enhancement you spoke
about.  It would be interesting to see.  Thanks in advance.

Kip Koon
computerdoc at sc.rr.com
http://www.cocopedia.com/wiki/index.php/Kip_Koon
http://computerpcdoc.com/


-----Original Message-----
From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Robert Gault
Sent: Friday, July 18, 2014 8:55 AM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] a not very important Drivewire question

Kip Koon wrote:
> Up to this point I was under the impression that the Coco 3 SECB was 
> executed first before any version of Disk BASIC and then it puts the 
> SB portion of the roms out of the way when Disk Basic was executed.  
> Is this not the case?  If not, then I can see why HDB-DOS is only 8KB.

 ><snip>

Kip,

You can study what SECB does by using the Unravelled series of books. In
general, the first thing a Coco does after the initial boot is run code at
$C000. With a Coco1 or Coco2, if $C000-$C001 is 'DK then Diskk Basic is
started. 
With a Coco3, the code at $C000 sets up the GIME, everything is copied from
ROM to RAM mode, the video parameters are set up, SECB is patched onto
Extended Basic,  and then finally the external disk ROM is enabled and, if
present, Disk Basic is started.

So, for a Coco3 in RAM mode, $8000-$BFFF is Extended Basic, $C000-$BFFF is
some Disk Basic, $E000-$FE00 is SECB. This still leaves 8K ROM memory in the
Disk controller available for enhancements. ADOS, for example, switches to
RAM/ROM mode to access this area. I wrote my own enhanced version of Disk
Basic utilizing a 16K ROM.

For the issue under discussion of printing documents via Drivewire, we
either need all new code that accesses the serial port or need to use the
dwread and dwwrite routines of HDBDOS (if possible) to access Drivewire.
Presumably one could send append DW control codes to the sent data to access
the DW "printer".

Robert


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