[Coco] Word-PAK RS Clone

[CoCo Demus]

just figured it out the board works from FF76-FF79 with these two decoders.

On Sun, Aug 13, 2017 at 10:02 AM, CoCo Demus <retrocanada76 at gmail.com>
wrote:

> I had to se 24x80 because some monitors would not display the 25th line
> due to overscan. Also not all R6545 are the same. I have two here and one
> settings does not work with the other. So I came up with a settings that
> works on both.
>
> Also I figured out how the FF76 is trapped with the 74LS10 and the 74LS133
> but the FF76+3 (used to write on the RAM chip) I still need to find it...
>
>
> On Sun, Aug 13, 2017 at 9:29 AM, Gene Heskett <gheskett at shentel.net>
> wrote:
>
>> 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>
>> >
>> > --
>> > Coco mailing list
>> > Coco at maltedmedia.com
>> > https://pairlist5.pair.net/mailman/listinfo/coco
>>
>>
>> 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>
>>
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> https://pairlist5.pair.net/mailman/listinfo/coco
>>
>
>