[Coco] Word-PAK RS Clone

[Gene Heskett]

On Sunday 13 August 2017 11:25:27 retrocanada76 wrote:

> i didnt changw because any mistake i would need to fab new boarda as
> the design is a little more complex for my electronic skills. but why
> you wod need a wordpak for cc3 anyway?
>
I was running 2 monitors on my cc3? An amber screen Maggy pc-80.

But the wp-rs's actual used area of the 13" screen was about the size of 
a post card.  So I played with the init values in the driver until the 
image was big enough to be useful, adding a 25th line while I was at it, 
but the 6116 cannot do more as its within 20 bytes or so of full at 25 
lines.

That code was submitted to the nitros9 repo, but in the grand re-write of 
all the scf stuff to modularize it, its was apparently considered to be 
junk code in co80 and friends that has been thrown away without even 
generating an email to me asking about it. One of the side effects of my 
screen expansion was that the h-sweep rate, originally in the 15750Hz 
rate range, was moved upward to a bit over 18 kilohertz, which the 
monitor could do but at reduced brightness due to the loss of a kilovolt 
or so of the crt's anode voltage.  The monitor was not endangered in any 
way otherwise since its going below the design frequency that allows the 
output transformer to saturate its ferrite core, in which event the 
currents reach part killing amperage in a microsecond or so since a 
saturated ferrite core effectively disappears along with the inductance, 
so the rate of rise goes up 10 to 100x.

And that lets the magic smoke out and it doesn't work any more. 
>
> Sent from my Samsung Galaxy smartphone.
> -------- Original message --------From: Gene Heskett
> <gheskett at shentel.net> Date: 2017-08-13  2:11 AM  (GMT-08:00) To:
> coco at maltedmedia.com Subject: Re: [Coco] Word-PAK RS Clone
>
> On Sunday 13 August 2017 03:23:37 CoCo Demus wrote:
> > Here, fresh from the press:
> >
> > https://sites.google.com/site/tandycocoloco/wordpak-rs
>
> Good for you! But your clone was too accurate.
>
> That $FF76 address means it straddles the boundary between 2 of the
> coco3 std 4 byte blocks of i/o. The one I still have, has been moved
> to $FF78, and my driver adjusted to compensate, so the offsets for the
> various registers are not 0,+1,-1,-2 as in the OEM driver, but
> 0,+1,+2,+3 which puts it all in one block of i/o, which the coco3 is
> criminally short of.
>
> This is why I have gone off on a rant several times begging someone to
> design an aftermarket decoder board kit to go into the coco3, freeing
> up the space from $FF04-$FF1F, 7 4 byte wide blocks of i/o, and from
> $FF24-FF3F, another 7 4 byte wide blocks of i/o.  Thats 14 more
> accessory cards that could be built if their address decoding was full
> to the 4 byte level, that could be designed, and plugged into the mpi
> or a clone of it, without encountering the dreaded "but that address
> is already used by card x" syndrome. Same idea with the floppy
> controller, which in its current OEM configuration, needs a 5 byte
> wide space, but that would free up 6 more 4 byte wide spaces. A better
> FDC could probably fix that and with a 512 byte buffer, could allow an
> FDC that could run at a megabaud, turning a QD 3.5" drive into a 2.88
> megabyte drive. Floppys are essentially extinct since drivewire is
> nearly as fast, and for nitros9 systems, there is no real size limit,
> I've a 105 megabyte floppy image that DW has no problems with, it just
> works. I haven't tested but using a cluster size some power of 2
> greater than the default 1, could allow a "floppy" image in the 4
> gigabyte area.
>
> Installing this "better address decoder" in the coco3 would not be for
> the faint of heart as it would be a bit invasive with the trace
> cutting and wire wrap wire for patches. But it could be done.
>
> Several of you have already demonstrated that you ARE capable of such
> a thing.
>
> So whats stopping one of you from making that your next big thing?
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <http://geneslinuxbox.net:6309/gene>
>
> --
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>