Author Topic: Some PCW Love - New Upgrades  (Read 404 times)

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Offline Charlie

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Some PCW Love - New Upgrades
« on: 18:59, 01 October 19 »
Hello all.
Personally I think the PCW needs more love so I thought I start a thread that pulls together an upgrade system I've been working on. This post will contain:
-The connection boards: One for internal upgrades, and one for external
-A modular external housing for the boards I've already designed along with a base Eagle layout should this prove popular
-Some explanation, starting now:

Having designed some upgrade boards for the PCW (untested but more info later) I thought it would be nice to package them in a way that would be accessible for any who might be interested in a bit of DIY, or possibly some ideas for others to use in their own projects.

Connection Boards:
The internal version is pretty simple and basically adapts the non-standard (thanks for the heads-up JonB) motherboard solder points just inside the external expansion connector to a standard 2x25-way connector. My boards come with the same connector and the idea is to use a 50-way SCSI ribbon cable as a flexible expansion bus to allow for 'flexible' placement of internal upgrades.
The external version is basically the same idea with the addition of a buffer IC on the data lines as there's more room and the added reliability may prove useful if lots of boards end up hanging off the expansion bus. As a bonus the boards are optionally stackable and I've designed a modular enclosure for them. This shouldn't preclude the use of 'classic' expansions where they have a pass-through connector or the owner feels happy to disassemble them.

So here's the first bunch. The links are to 3D mock-ups and the .zip files contain the important stuff.

PCW_Expansion_Connector_v2
https://autode.sk/2ntV3oX

PCW_Expansion_Connector_External_v1
https://autode.sk/2ogJjWM

PCW_Box_v10
https://autode.sk/2p3OOc5


PS
I designed and made a Yamaha 9958 expansion for the Coleco ADAM recently (still getting round to making a lead to actually test it). All part of a dastardly plan to add basic MSX2+ and 80 column support to the ADAM. Assuming the thing works and there's interest (I'm not that great on getting round to completing stuff) it wouldn't be that hard to convert for PCW use... fiddle with the AY-based expansion I'll post shortly (DK'tronics compatible ATM), 'borrow' some RC2014 software, and MSX games on the PCW could be a reality.
« Last Edit: 01:25, 02 October 19 by Charlie »
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Offline Charlie

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Re: Some PCW Love - New Upgrades
« Reply #1 on: 01:24, 02 October 19 »
Round two... yes, yes, I know I've posted much of this stuff already but here be updates, pretty pictures, and putting it all together.

PCW I/O:
A combination board intended to cover the bases for PCW expansion.
There's a proper composite video interface for safe connection of an external monitor, or in my case a monitor as I'm building an 8512 motherboard in to an 8256 keyboard.
There's an SIO/2 for dual FTDI compatible serial ports. It follows the Zilog datasheet quite closely and has selectable port addresses so shouldn't be too hard to get working - no, I'm not great at coding.
There's also a uIDE compatible (I hope!) IDE interface for... IDE. Again because hardware needs software and I'm no coder. I would like to take the belated opportunity to thank JonB for his awesome work and to say that anyone who isn't after a multi-function solution really should go support the developer and get one of his (properly tested) boards instead.

PCW_I/O_v1:
https://autode.sk/2nrC8LG

PCW 8255 IDE:
Another IDE interface based on the 8255 inspired by Yarek's design. I'm hoping there's a CPC CP/M driver than can be re-purposed for the PCW... I'm a bit of an ideas to schematic kind of person, thought (if any!) sometimes comes later.

PCW_8255_IDE_v1:
https://autode.sk/2nAj4KY


...more on the way.
Charlie.

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Offline Charlie

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Re: Some PCW Love - New Upgrades
« Reply #2 on: 19:12, 02 October 19 »
Round three

Here are the last two boards I've designed specifically for the PCW so far.

PCW RAM:
It's a 2Mb upgrade with a couple of twists... assuming I did it right! The most obvious is the inclusion of a CR2032 for battery backup. Hopefully that means a nice big RAM disc under CP/M that will keep it's contents when the computer is off. The SRAM I chose is somewhat bigger than 2Mb. Convenient that enough RAM is in a single package, wasteful that the majority of said RAM goes to waste... With that in mind I added two extra 2Mb banks that function exactly as PCW RAM is supposed to but located at two other base addresses.
The banks are:
F*H - Standard addressing
B*H - Alternate "B"
7*H - Alternate "7"
3*H - Unavailable
That accounts for 6 of the possible 8Mb. I'm afraid the way I've constructed the addressing logic you can't get at the 3*H bank. I guess I could have changed that but it was a balance between minimal IC count and maximal memory availability. This card *should* work as a 2Mb upgrade as the PCW and it's software won't be aware of the others but even with my shoddy coding ability it wouldn't be hard to put those extra baks to work if desired.

PCW RAM v4:
https://autode.sk/2os9mul

PCW Sound:
My final design, for now, is another multi-function board. This time DK'tronics Sound and Game Port compatible with the addition of CPC Digiblaster compatibility. Being fairly new to the PCW I'm not aware if there's much support for the former (Head over Heels) but I guess the more people have such a board the more likely anyone minded to code / convert games to the PCW might be inclined to include such support. I added Digiblaster compatible support because... why not? It wasn't a problem to implement and I hope (not checked!) there's already software out there that will run on the PCW (with minor changes) even if it's only to play a few samples.
The card's output is mono to keep the component count down but if there was demand a stereo version is possible.
Assuming I get round to testing my Coleco ADAM 9958 card, it proves functional, and I do a version for the PCW, I'll probably add MSX compatibility to a new version of the sound card and see if the PCW can be persuaded to play some MSX(2+) games.

PCW Sound v1:
https://autode.sk/2n1o0se

I think that's me done for the time-being. While none of this stuff is tested I hope these designs are of interest and even prove to be functional.


https://www.youtube.com/watch?v=jQ0p30u0Ue4
« Last Edit: 19:19, 02 October 19 by Charlie »
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LambdaMikel

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Re: Some PCW Love - New Upgrades
« Reply #3 on: 19:36, 02 October 19 »
I think that's me done for the time-being. While none of this stuff is tested I hope these designs are of interest and even prove to be functional.


Hmm, I appreciate your drive - but I am afraid that the people that would be capable of wrapping up your work would rather spend their time designing their own extensions. That might be faster / more productive for them than trying to figure out what you did.

So not quite sure what the point is of pushing all these untested / unfinished designs.... But thanks anyway!


Rather than dumping them here, it might be preferable to upload them to GitHub or similar and make it an open source project. That might yield more community participation. Just an idea.
« Last Edit: 20:00, 02 October 19 by LambdaMikel »

Offline JonB

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Re: Some PCW Love - New Upgrades
« Reply #4 on: 20:38, 02 October 19 »
+1 but I wouldn't want to discourage you, Charlie.

As I said before, a Dk'tronics type sound card with programmable I/O base (so, "universal") that connects to the Z80 bus is my next design. Or perhaps a PCW uIDE boot board...

Offline JohnElliott

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Re: Some PCW Love - New Upgrades
« Reply #5 on: 14:37, 03 October 19 »

PCW RAM:
It's a 2Mb upgrade with a couple of twists... assuming I did it right! The most obvious is the inclusion of a CR2032 for battery backup. Hopefully that means a nice big RAM disc under CP/M that will keep it's contents when the computer is off.
Preserving the 'normal' RAMdisc wouldn't be straightforward -- you'd need to patch CP/M and LocoScript not to initialise the RAMdisc when it starts, and the RAMdisc isn't the same size under the two operating systems so dual-booting would erase it anyway.
On the other hand, it sounds as if it would be straightforward to create a .FID that accessed the extra 4Mb as a standalone battery-backed RAMdisc.

Offline Charlie

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Re: Some PCW Love - New Upgrades
« Reply #6 on: 23:17, 03 October 19 »
That's quite ok chaps, I do get your point and it is a perfectly valid one.

The issue is I'm no-longer in a position to make / test the various designs and ideas I have hanging about for a few retro systems, so there's little chance I'll be developing these for the foreseeable future. With that in mind, rather than doing nothing, I've been finishing stuff as far as I can to post what I do have in case it's of interest or indeed inspiration to others.

With that in mind I have one more unfinished project to post; a PCW GFX card based on my Coleco design that I'm frustrated to report has been finished for a while but remains untested.

So here goes, PCW 9958-based GFX card:
https://autode.sk/31Iz7Fn

The Yamaha 9958 is an awesome "classic" GFX chip that is backward compatible with the TMS9918 as found in the Ti 99/4A, Colecovision and ADAM, and MSX. It was developed for the MSX2+ / TurboR and although no-longer in production is still readily available for reasonable prices.
From a practicable point of view it uses it's own VRAM, only needs 4 ports for communication, and requires very little support circuitry, which makes it a good option for anyone who wants to add some extra colour / resolution / sprites / etc to an existing system. Indeed, as I already have most of the necessary circuitry I was intending to eventually do my own MSX2+ design for "fun" in a similar vein to the Harlequin Spectrum, oh-well.

I hope my recent splurge has been more interesting than frustrating. All the best. :-)
« Last Edit: 23:22, 03 October 19 by Charlie »
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