[Coco] 80 column pak prototype

Wed Oct 23 14:22:43 EDT 2013

Nice, this board uses a LS133 for all H addresses and a LS138 for the L
adresses and CLK for strobing. Maybe I can replace the LS138 for this LS688
and jumper the lower bits. Leaving the CLK as H on comparator would make it
strobe.

Back to design again... :/

On Wed, Oct 23, 2013 at 1:50 PM, Mark Marlette <mmarlette at frontiernet.net>wrote:

> Luis,
>
> Always fun shoehorning  something into the CoCo's map.
>
> FF74/FF75 was the TC^3 default space. Nice to be able to move around.
>
> Look at a 74LS688, that way you could set the jumpers how ever you would
> like.
>
> Regards,
>
> Mark
>
>
>
>
> ________________________________
>  From: Luis Antoniosi (CoCoDemus) <retrocanada76 at gmail.com>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Wednesday, October 23, 2013 11:43 AM
> Subject: Re: [Coco] 80 column pak prototype
>
>
> Mark you might be right about the weak signal. If it was a wrong bit all
> instances of the same character would be changed what is not the case.
> Also, cursor positioning seems to be working and they all use the same data
> bus.
>
> Another topic, should I keep the FF78/79  or should use: FF76/77, FF74/75
> or even FF72/73 ?
>
> The FF78/79 is the same of the superIDE RTC. It's is going to mess with it
> when using together.
>
>
>
>
> On Wed, Oct 23, 2013 at 8:59 AM, Mark Marlette <mmarlette at frontiernet.net
> >wrote:
>
> > Luis,
> >
> > Fun stuff!
> >
> > On the note of strange characters. As it appears that these proto-boards
> > are a good thing, they are not good for digital design at MHZ rates.
> >
> > The CoCo's address bus is not buffered, unless you have a Pro-Tector+, so
> > just driving through the ribbon cable to your board will be degraded. My
> > tests shown ~3-4" was max, YMMV.
> >
> > The proto-board adds capacitance to every point, some cases that is good,
> > most cases it is not.
> >
> > So your circuit can be wired electrically correct and it still will not
> > work just by how you physically built it. That is not to say you don't
> have
> > a wiring issue. :)
> >
> > Generally it is cheaper and will yeild better results to have a board
> made.
> >
> > My $0.02.
> >
> > Any case, enjoy and continue your great work on the software and
> hardware!
> >
> > Regards,
> >
> > Mark
> > http://www.cloud9tech.com
> >
> >
> >
> >
> >
> >
> > ________________________________
> >  From: Luis Antoniosi (CoCoDemus) <retrocanada76 at gmail.com>
> > To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> > Sent: Wednesday, October 23, 2013 6:52 AM
> > Subject: [Coco] 80 column pak prototype
> >
> >
> > Hi all,
> >
> > Having all the components at hand I started prototyping yesterday:
> >
> > pic.twitter.com/aAnpm39NwL <http://t.co/aAnpm39NwL>
> >
> > One hour later:
> >
> > pic.twitter.com/dOEpz5Y91K <http://t.co/dOEpz5Y91K>
> >
> > And turning this thing on:
> >
> > pic.twitter.com/rl4fNtssfa <http://t.co/rl4fNtssfa>
> >
> > You can see some characters are strange, I must have swapped a bit in the
> > data bus or something. It was too late yesterday to troubeshooting but
> HEY
> > IT WORKS!
> >
> > Those protoboard jumpers are really helpful. :)
> >
> > --
> > Long live the CoCo
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > http://five.pairlist.net/mailman/listinfo/coco
> >
> > --
> > Coco mailing list
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>
> >
>
>
>
> --
> Long live the CoCo
>
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>
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>

-- 
Long live the CoCo