[Coco] 80 column pak prototype

[Mark Marlette]

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
>
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>



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