gene.heskett at verizon.net
Tue Jul 15 08:11:04 EDT 2008
On Tuesday 15 July 2008, Arthur Flexser wrote:
>I have some recollection of the differences between the 3 models. The
> Wordpak II differed from the original PBJ Wordpak (or am I remembering PBJ
> as the maker's initials on account of peanut butter and jelly?) in that its
> display memory could be upgraded, to allow swapping in different screens
> worth of display by switching the display origin.
>The Wordpak-RS was a version sold by RS (though only through the Express
> Order program, I believe), and had a different base address, presumably to
> avoid address conflicts with something or other.
Its been 15 years since I did it, but I have an RS model, and one of the first
things I did to it was to fix the broken address decoding. On the coco, most
peripherals need a 4 byte block of addresses and the RS is no different in that
regard. But the stock decoding used the upper two bytes of one block, and the
lower 2 bytes of the next one up, effectively using 8 bytes in the coco3's very
precious I/O space. That was fairly easy to fix and the snooping for where to
fix the driver for the address changes led to some other driver changes too.
At that time, the os9 driver for it was co80, and it has an initialization table
that is fed to the 6845 at bootup as the 6845 has 32 internal registers that
control its operation. As the stock display used an 80x24 area on a 13" amber
screen that was actually about the size of a postcard, with 2 to 3" of wasted
space around it, I changed some of those values which had the effect of running
the monitor at about 18.5 khz horizontal and around 75 or 80 hz vertically.
The magnavox PC Monitor 80 is quite tolerant and it ran that way on my machine,
with the 80x24 display nearly filling the 13" display for about 10 years.
With only a 6116 for memory, the display was limited to 80x25 maximum. With
additional memory it could have just as easily handled a 132x72 screen. Had
there been larger cmos memories available at the time, I might have gone that
One other change I made was to give it a ttl output on a db9 connector, much
more stable synch.
>On Mon, 14 Jul 2008, Chuck Youse wrote:
>> Hi folks,
>> It looks like tomorrow I'm going to be coming into possession of much
>> cool Coco gear, including a "Wordpak". Now, back in my 64K Coco 2 days
>> I drooled much over this mystical item described in Rainbow magazine,
>> and I'm very much looking forward to getting it going.
>> Question is, does anyone know ANYTHING about it? Google isn't too
>> helpful, I see references to a Wordpak, Wordpak II, and a Wordpak RS.
>> There is a NitrOS-9 driver for the Wordpak II that sheds some light.
>> (Looks like a 6845-based card.) But does anyone know what the
>> differences in the models are? Does it have a composite output? Any
>> info appreciated.
>> Coco mailing list
>> Coco at maltedmedia.com
>Coco mailing list
>Coco at maltedmedia.com
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