Dragon 64

From: Al Hartman <alhartman_at_yahoo.com>
Date: Thu Mar 6 16:32:28 2003

oops!

Guess that was wrong.

I can remember using a Tandy Controller on a Dragon 32
once. But, I guess that one had hacked Coco ROMS.

That might be what I do with this unit, hack a set
Coco ROMS to go into it, just to get it working again.

With a new unit at $35.00, it might not make much
sense to try to get this one working again.

My Coco III is also dead. Green box with no text. I
think the 6809 is bad. At least, that's what I've been
told about these units. So, I'd have to desolder it
and put another one in just to diagnose it.

I may do that some weekend when I feel adventurous.

Suddenly caught the old computer bug....

Al

> From: tlindner_at_ix.netcom.com (tim lindner)
>
> > I know I can use a Tandy Controller, but I think
> > I'll need a different Disk Basic ROM for it. If
> > anyone can help with that, I'd be obliged...
>
> Lets see...
>
> The Tandy controller/software uses the following:
>
> Read byte, store byte, halt CPU, un-halt CPU,
> repeat. NMI when done.
>
> The Dragon controller/software uses the following:
>
> SYNC, interrupt, read byte, store byte, repeat. NMI
> when done.
>
> On the Tandy controller DSKREG is $FF40, and the
> wd179x is mapped
> between $FF48-$FF51.
>
> On the Dragon controller DSKREG is $FF48, and the
> wd179x is mapped
> between $FF40-$FF43.
>
> Also the bit patterns for DSKREG are different
> between the Tandy and
> Dragon controllers:
>
> *
>
---------------------------------------------------------------
> * DSKREG - the control register
> * CoCo ($ff40) Dragon
> ($ff48)
> *
> * Bit Bit
> * 7 halt enable flag 7 not used
> * 6 drive select #3 6 not used
> * 5 density (0=single, 1=double) 5 NMI enable
> flag
> * and NMI enable flag
> * 4 write precompensation 4 write
> precompensation
> * 3 drive motor activation 3 single
> density enable
> * 2 drive select #2 2 drive
> motor activation
> * 1 drive select #1 1 drive
> select high bit
> * 0 drive select #0 0 drive
> select low bit
>
>
> It would take some serious hacking to transform a
> CoCo FDC into a Dragon
> FDC.
>
> --
> The ears are too length.
>
--------------------------------------------------------
> tim lindner
> tlindner_at_ix.netcom.com
Received on Thu Mar 06 2003 - 16:32:28 GMT