[Coco] Word-PAK RS Clone

Sun Aug 13 14:38:35 EDT 2017

On Sunday 13 August 2017 13:02:47 CoCo Demus 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...
>
NP, that is decoded as $FF79 where the +2 is decoded as $FF78. Normally 
the next 4 byte wide i/o block would start at $FF74, not 76. Because 
that tied up 2 i/o blocks, I moved mine to $FF78 so its all in one 4 
byte wide block. 

Any new designs should be nice to each other, and adhere to the /4 as its 
base address.

> 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

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>