Author Topic: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project  (Read 69432 times)

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Offline djosTopic starter

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G'day All, my current project is a Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card design and build. technically it's stupidly straight forward. The Tandy 1000 ex/hx PLUS Expansion connector is a 62 Pin IDC style connector which is electrically compatible with the IBM 8-Bit ISA edge card's. It wont even need any components other than a Right angle female IDC header & two 8-Bit ISA Slots.

So rather than Bodge something up on Proto-Board, I thought I'd design something properly in Eagle and use that as an excuse to learn Eagle at the same time. I've found some excellent tutorials on Eagle from Jeremy Blum and I've had lots of fun downloading loads of parts Libraries (I got the entire Element 14 collection) and trawling thru them.

I'm kinda stuck atm tho - part of the issue is the pc-con library has the 8-Bit ISA Edge connector part but not the 8-Bit ISA Slot; It has the 16-Bit ISA Slot tho.

The other challenge I've found is the IDC style connector, my Riser Board needs a 62-Pin right angle Female Header, but there isnt one in all the libraries I have.

So I thought maybe I could customise the 16-Bit ISA Slot (chop the smaller 16-Bit extension off the end) and also cut down a larger header to 62 Pins. However i'm not finding any good tutorials on how to do this - I did find one but the version of Eagle being used was v5 (iirc) and it merely confused me as the UI seems to have changed quite a bit in some areas. Any ideas from the Eagle pro's here?

Anyhoo, here's the 8-Bit ISA specs: http://www.hamradio.cc/computer/isa_bus_pinouts.php

and the Tandy 1000ex Technical reference Manual: ftp://ftp.oldskool.org/pub/tvdog/tandy1000/documents/extech.zip

For Parts Supply, I cant find and caches of 8-Bit ISA Slots or right angle 62-pin female headers floating around the net (I doubt Sullins will fire up their production line for my tiny requirements) so I'm going to scavenge the 8-Bit ISA Slots from an old 286 Mainboard and cut down some right angle 64-pin female headers to 62-pin.

Offline bitseeker

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #1 on: April 26, 2017, 08:03:49 pm »
Yep, any old XT/AT motherboard should be fine as a connector donor.

Does this mean you found a 1000?
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Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #2 on: April 26, 2017, 08:49:52 pm »
Yep, any old XT/AT motherboard should be fine as a connector donor.

Does this mean you found a 1000?

Not yet but I can't help myself and I'll design and build this while I wait for the right unit. I know there are other Tandy 1000ex / hx owners out there who would like a tidy solution too as I've seen a few folk using bodged up solutions using ribbon cables etc. So I plan to do small run of boards once I get it right.

Offline bitseeker

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #3 on: April 26, 2017, 10:01:56 pm »
Sounds good! I was just curious.
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Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #4 on: April 26, 2017, 10:09:17 pm »
Btw I found a supplier in Hong Kong (XinYu Technology Industry Limited) who claims to have new Sullins Connector Solutions EBC31DCWN-S371 ISA slots in stock for $6.50 USD each, so I may not need to sacrifice an old mainboard after all.

I also figured out how to clone and edit parts in Eagle, boy is it painful tho, the graphics editing abilities are horrendous, it'd be easier to draw the board view connector on my Amiga 500 in deluxe paint!

P.s. Any questions or constructive criticism is entirely welcome, I've never designed a pcb before so this is all undiscovered country for me. Previously I've just made one off proto-board's with no thought to doing it nicely.

Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #5 on: April 26, 2017, 11:52:39 pm »
For those wondering why I'm bothering, the Tandy 1000 ex/hx use a stacking system for expansion cards with the 8-Bit cards placed horizontally on top of the ram/dma board:

here's an unpopulated expansion bay:



and here you can see two cards stacked on top of each other:



and this is the Ram/DMA expansion card that my PLUS-ISA Riser card will plug into - the idea is to slot into the bottom slot (on the left in the pic) and allow for 2x 8-Bit ISA cards to be installed horizontally. I plan to use the riser board to install an XT-IDE card (Im building that atm) and a NOS 8-Bit Serial card I found on FLeaBay (so I can use a serial mouse) into a yet to be purchased Tandy 1000 ex.


Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #6 on: May 05, 2017, 01:15:44 am »
Parts are starting to come in, I just need to finish designing the PCB now.

I acquired an old 386 MB with the separate 8-Bit ISA slots I can desolder and reuse - there's enough to make 4 2-slot adaptor boards.  8)


Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #7 on: May 05, 2017, 05:03:31 am »
Huzzah, I finally found the 62 pin right-angle headers I need on Digi-key!  8)

https://www.digikey.com/product-detail/en/sullins-connector-solutions/PPPC312LJBN-RC/S5584-ND/776042


Offline bitseeker

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #8 on: May 05, 2017, 04:56:22 pm »
It's kind of funny that the photo of that old motherboard has a watermark "k-collectibles" and then the collectible is about to have its parts re-purposed. ;D
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Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #9 on: May 05, 2017, 09:45:35 pm »
It's kind of funny that the photo of that old motherboard has a watermark "k-collectibles" and then the collectible is about to have its parts re-purposed. ;D

Lol, yeah clone 386 boards are hardly collectable.  ;D

Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #10 on: May 07, 2017, 04:49:34 am »
So finally making progress learning Eagle and succeeded in building an 8-Bit ISA Slot part. I found a physically & electrically compatible 62-pin male header which saved me the trouble of dodging up right-angle female header as everything on the PCB is identical.

I'm not impressed with the auto-router tho, the result is a bit rubbish ... although that may be my inexperience showing.  :-\

I haven't bothered doing any physical measurements yet so the PCB part placement is very rough .. I'll wait till bait theory gets me my 1000ex and then I'll print out mock up's on paper and tweak as required before getting the PCB's made up.


Online krho

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #11 on: May 07, 2017, 06:00:09 am »
Your schematic is completely unreadable.
I don't know eagle but There should be something named BUS or like that that would help you draw a readable schematic.
 

Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #12 on: May 07, 2017, 06:07:24 am »
Your schematic is completely unreadable.
I don't know eagle but There should be something named BUS or like that that would help you draw a readable schematic.

It's ridiculously simple, just straight connections from "Row 1" of the header to "Row A" of each Slot and from "Row 2" of the header to "Row B" of each Slot.

PS, I think my tracks are too thick to pass between the pins of the slots resulting in the horrendous mess above!   :palm:

PSS, there is a bus option but I have no idea how to use it..... yet.  :-[

Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #13 on: May 21, 2017, 01:59:28 am »
So I gave up on Eagle (what a POS) and gave DipTrace a go on my old dual boot MacBook - wow, so much better to use in most areas. Finding components is a bit harder but everything else is orders of magnitude easier to use!

I made this in 2 hours and sure the schematic is ugly as sin (why bother with buses when the design is so simple) but the PCB design was dead easy. I need to finish it off but at least being able to use the right size parts resulted in a auto-router getting it mostly right on the first go!





That said, now I have a better understanding of DipTrace, I'll do it again properly when I have time.

Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #14 on: May 22, 2017, 01:58:19 am »
Hmmm, sometimes the simple solutions are the best. I still plan to make the PCB based adaptor however in the meantime I made this ribbon cable PLUS-ISA adaptor (and a couple of Lo-tech ISA CompactFlash Adaptors too).

I couldnt get 62 Pin IDC edge connectors and used a 64 pin IDC edge connector instead - I'll prolly stuff a plastic blocker in the far end to prevent incorrect card insertions.



Offline bitseeker

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #15 on: May 22, 2017, 09:08:58 pm »
Yep, sometimes just go with what works at the moment. :-+
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Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #16 on: May 23, 2017, 04:03:17 am »
Yep, sometimes just go with what works at the moment. :-+

Too true mate.

I realised I forgot to order the 2.2uF Tantalum Caps to enable 5v via the key pin (p20) on the XT-IDE header, so I've banged off an order to RS for some. I've also modded some cheap IDE-CF adaptors to use p20 for power by adding the missing pin 20, desoldering the Floppy power connector and adding a mod wire from pin 20 to the 5v input.  8)



PS, the huge solder-blob on the modded adaptor was there from the factory.  :palm:

Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #17 on: May 31, 2017, 10:06:52 pm »
I stumbled across a cache of NOS 8 Bit ISA slots recently and couldnt help myself, I bought a lot of 50 which worked out to $1 AUD each shipped! Winner winner, chicken dinner!  ;D



I guess I should really pull my finger out and finish designing this board!  :-DD

Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #18 on: June 01, 2017, 04:39:29 am »
Im thinking that now I have so many ISA slots, I might change the design concept to be a single 1-to-1 slot adapter. That way if folks have a PLUS Serial card they wish to keep, they can just install a single adapter in the tallest PLUS expansion socket to install an ISA card. And if they want to install 2x ISA cards, they install 2x adapters, 1 per PLUS expansion socket.

I think it will be a more flexible solution ... and simpler and cheaper.

Offline bitseeker

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #19 on: June 01, 2017, 10:40:44 pm »
That's a lot of ISA sockets! ^-^
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Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #20 on: June 01, 2017, 10:52:10 pm »
That's a lot of ISA sockets! ^-^

Not wrong, I see a lot of soldering in my future!  ;D

Offline bitseeker

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #21 on: June 01, 2017, 11:00:48 pm »
You could make yourself quite a bus expansion chassis and case for more than just two cards.
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Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #22 on: June 01, 2017, 11:07:42 pm »
You could make yourself quite a bus expansion chassis and case for more than just two cards.

Quite true and I have considered it. I prolly won't bother simply because the 1000ex has built in sound and 16 color enhanced CGA graphics so all it needs is a serial port for a mouse and mass storage. I suppose I could add an EMS memory card but for the era of games I plan to use it for, there isn't much point.

Offline bitseeker

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #23 on: June 05, 2017, 03:42:40 am »
Perhaps an EGA card for more colors on games that support it, but you'd probably have to be able to disable the onboard CGA.
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Offline djosTopic starter

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Re: Tandy 1000 ex/hx PLUS Expansion to 8-Bit ISA Riser card project
« Reply #24 on: June 05, 2017, 04:20:49 am »
Perhaps an EGA card for more colors on games that support it, but you'd probably have to be able to disable the onboard CGA.

Tandy CGA already supports 16 colors and there's a huge amount of XT games that support it. One option would be to use an 8 bit VGA card, however I'm fairly certain the 1000ex has no way of disabling the onboard video.


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