[Coco] a not very important Drivewire question

[Robert Gault]

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