[Coco] cartridge prototype board

[Gene Heskett]

On Sunday 28 September 2014 17:11:17 Kip Koon did opine
And Gene did reply:
> Hi Guys!
> Would we want some type of minimum Address Bus decoding on the
> Cartridge Protyping PCB or leave it totally covered with solderable
> holes and no circuit whatsoever.  How about buffer chips on all the
> signal lines in case the user makes a mistake.  That way the Coco
> would not be harmed.  Only the socketed buffer chips would need
> replacing.
> There are 32-bytes in the space allotted for the electronics in
> cartridge paks, but not every product would need them all.  Besides by
> now certain addresses have become known to be used for certain
> functions like those used by floppy and IDE hard drive controllers,
> serial port controllers, and multifunction paks like the IR-Tech pak,
> the Disto paks and much more.  I would be interested in a copy of a
> document detailing absolutely all the uses of the addresses in the
> $FFxx I/O block if anyone has the addresses collected together in one
> place.  I have seen some documentation detailing the entire $FFxx area
> in the past which looked absolutely full but it had "todos" here there
> and yonder for explanations of things not included yet. There was no
> memory address unused at some point or other.  How is the $FExx block
> used?  I remember someone mentioning about needing to write something
> in the $FE00 area to get something to work in the Coco 3, but I don't
> remember what that was talking about.

$FFE0-FFFF is AIR, (and I'm trolling in awfully ancient wet ram here so 
double-check me folks) reserved for the system hardware in both coco 
families.  IIRC even if in the all ram mode, those last 2 pages are 
switched back to rom by one or the other of the gfx chips, gime or the 
coco1-2 6847.

> I have also been thinking of designing a cartridge prototyping PCB, but
> I didn't know whether or not to go ahead and put decoding glue logic
> on it or not.  Maybe some type of configurable circuit to place the
> users project anywhere in the $FFxx block, and not just in the $FF40 -
> $FF5F 32 byte block.  I'll keep thinking on this and see what happens.
>  Take care my friends.

What we really need before going off in 739 directions looking for 
hardware addressing space in the $FFxx page, is for someone to develop a 
cut it into the circuit easily board that replaces ALL of the $FFxx 
decoding that is so sloppily done by tandy when they wasted 32 bytes for 
every device, and with the singular exception of someone designing a 16550 
based serial port that needs 16 bytes, and some totally screwed decoding 
in the WP_RS that CAN be fixed, mine is, everything else we have can make 
do with a 4 byte wide decode except the floppy controllers.  The floppy 
controllers would need $ff40-43, and $FF48 but even that could be moved to 
$FF44 although that would need basic patches.  Not worth the effort, by 
even leaving it at $FF48, we would still have $FF44-47 for use someplace 
else IF we had 4 byte wide decoding.  That is room for a pia and 4 more 
bit bangers or 2 parports right there folks. Ditto for $FF49-4C, another 
pia=4 more bit bangers.

Simply by decoding to 4 byte wide cs lines for the motherboard PIA's, 7 
more bits and pieces of hardware needing the usual 4 byte wide address can 
be fitted into the $FF00-FF3F area alone.

Nitros9 would likely need an expanded IRQ & VIRQ table.  That is something 
I haven't investigated recently.

> Kip Koon
> computerdoc at sc.rr.com
> http://www.cocopedia.com/wiki/index.php/Kip_Koon
> http://computerpcdoc.com/
> 
> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of didier
> derny Sent: Sunday, September 28, 2014 4:24 PM
> To: 'CoCoList for Color Computer Enthusiasts'
> Subject: Re: [Coco] cartridge prototype board
> 
> If some were produce I could but buy between 7..15 depending on the
> price
> 
> --
> Didier
> 
> 
> -----Message d'origine-----
> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de Carlos
> Santiago Envoyé : dimanche 28 septembre 2014 21:53 ہ : CoCoList for
> Color Computer Enthusiasts Objet : Re: [Coco] cartridge prototype
> board
> 
> Hello,
> 
> If there is an interest in a prototype board for the CoCo. I would be
> interested in designing one for sale. I just need to know what the
> level of interest is.
> 
> My Company is called Electronics Is Fun. I am the founder  and I do all
> the engineering. My main focus is on helping people learn about
> electronics and build projects. I am a distributor for Arduino and I
> also have a Parallax propeller board called the propeller charlie for
> this of you that have interest in these types of boards.
> 
> I am a long time Coco enthusiast and I own a Coco1, Coco2, Coco3 and a
> Micro Color computer.
> 
> I am also considering some type of VGA output for the Coco in cartridge
> form to allow my Coco’s to be used with a VGA monitor.
> 
> If these Ideas interest you, please contact me and we can discuss them
> further.
> 
> I can  be reached directly at ElectronicsIsFun at Gmail.com or here on the
> CocoList.
> 
> Thank You,
> Carlos Santiago A.K.A GuruSantiago
> ElectronicsIsFun at Gmail.com
> 
> 
> On Sep 28, 2014, at 1:57 PM, RETRO Innovations <go4retro at go4retro.com>
> 
> wrote:
> > On 9/28/2014 1:54 PM, Zippster wrote:
> >> Should be pretty easy to draw up in Eagle and have made by OshPark
> >> or the
> 
> like.
> 
> >> What size / features do you guys think would be best?
> > 
> > My thoughts exactly.  I was planning to build one to do some
> 
> CPLD/prototyping work, and I'd be happy to buy them in bulk (100) to
> get the price more reasonable.
> 
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco


Cheers, Gene Heskett
-- 
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US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS