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Tandy 1000 Adapters - expressions of interest?

dJOS

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G'day Guy's, Im in the process of making some Tandy 1000 Adapters mainly for myself (for my 1000 EX) but I'm curious to know if there is much interest in these from others?

I've designed PCB's the following parts:

  1. Tandy 1000 EX / HX PLUS to ISA Expansion adapter (requires the DMA/RAM expansion installed) = $15 USD
  2. Tandy 1000 EX / HX external Floppy Drive replacement cable = $19 USD
  3. Tandy 1000 Edge Connector to DB25 Parallel port Adapter = $TBD

Shipping to the USA would be $5 USD per item or $25 USD for multiple items together ($5 = a is a bit of a cheat using a "large letter" hence the cost disparity)


I've made 5 of Item #2 already and just need to test them - I have about 2 or 3 spares left as at least 1 is already spoken for.

I have 10 PCB's for Item #1 enroute from china atm and will have approximately 6 left over as I already know a couple of folks that want one.

Item #3 only exists in my head atm but is dead simple to design and build - I'll make a small run if folks are interested.


Just to be clear, this topic ISNT a "for sale" topic, I'm just trying to gauge interest from the Tandy 1000 owners here. If I get enough interest I'll finish / build the items and then start a for sale topic in the marketplace. I wont take anyones money until I've got finished and tested adapters in my hot little hands.
 

dJOS

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Pic's:

Item #1

This is actually my v7 design which while it works, has some minor issues. v8 is more compact and cheaper to make as the PCB is shorter (there's no need for the mounting holes on either side). v8 also has the right angle header mounted on the front side of the board.
EYl5Z4sl.jpg


v8 Design:
eWUulPsl.png


Item #2
Replacement external FDD Cable:
rHMvo7wl.jpg


Item #3
Haven't laid out the PCB yet, will add a PCB design Pic a bit later this weekend.
 
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Tibs

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How difficult would it be to make an adapter to allow three ISA cards? HX was my first MSDOS computer and would love to get one, but the lack of cards makes it a no starter for me. I'd love to have a serial and or ethernet ISA card in one.
 

keenerb

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I'd be interested in several of the card-edge to DB25 printer adapters.

Also at least one ISA expansion adapter for my EX.
 

dJOS

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How difficult would it be to make an adapter to allow three ISA cards? HX was my first MSDOS computer and would love to get one, but the lack of cards makes it a no starter for me. I'd love to have a serial and or ethernet ISA card in one.

Quite easy actually, it would need to go into the lower expansion connector due the height needed - I'd have to check to make sure tho. The memory expansion is mandatory tho as most cards won't work without the DMA controller.
 

Tibs

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Is there an ISA memory card that would solve that problem? Finding the plus ram card isn't quite that bad though.
 

dJOS

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Is there an ISA memory card that would solve that problem? Finding the plus ram card isn't quite that bad though.

My understanding is the PLUS-Ram card has a custom DMA controller integrated into the memory controller chip - without it only simple cards like a serial card / modem will work. Anything else like an ethernet card or IDE controller wont function without it.

Without the PLUS-Ram card there is no DMA function in the system - once installed it makes a noticeable difference to the speed of the machine, even the floppy drive speeds improve.
 

keenerb

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Is there an ISA memory card that would solve that problem? Finding the plus ram card isn't quite that bad though.

Something like James Pearce' 1mb memory card would probably work in the riser. Doesn't offer DMA capabilities but if all you're looking for is memory expansion past 128k it'd be sufficient.

An EX/HX with 1MB expansion + non-DMA xt-ide would actually be pretty usable.
 

dJOS

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Then probably just need one with two slots.

In that case (assuming it works) my intention is that you would buy 2 adapters and put 1 in each socket - it's just easier for me to make a single design that works for everyone with the ram expansion.

PS the NEC V20 upgrade is apparently worthwhile for EX/HX owners as it add's support for some useful 286 instructions making the compatible software pool larger.

5SYH5BEl.jpg
 
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dJOS

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Something like James Pearce' 1mb memory card would probably work in the riser. Doesn't offer DMA capabilities but if all you're looking for is memory expansion past 128k it'd be sufficient.

An EX/HX with 1MB expansion + non-DMA xt-ide would actually be pretty usable.

I guess the XT-IDE would would in PIO mode but it'd be extremely slow as the CPU has to do all the work for everything, the BIU mode (using the 8088's Bus Interface Unit) might also work too.
 

eeguru

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My understanding is the PLUS-Ram card has a custom DMA controller integrated into the memory controller chip - without it only simple cards like a serial card / modem will work. Anything else like an ethernet card or IDE controller wont function without it.

Without the PLUS-Ram card there is no DMA function in the system - once installed it makes a noticeable difference to the speed of the machine, even the floppy drive speeds improve.

That's completely not true. PIO IDE works just fine (what XT-IDE uses). The only thing it accelerates on the stock system is floppy drive access. Nothing else get's sped-up. Even most network cards work just fine without DMA. Many early Ethernet adapters do not even support DMA (eg. NE1K/2K, Xircom, etc) and many more do not require it.

I had layed out a memory mapped Plus card similar to JR-IDE with the addition of two serial ports, but never could find a solution for the elevated 62 pin connector. The best path I found forward was, possibly, to make a two card set with a normal-ish height female connector downward and slightly taller male connector upward. One card with RAM, IDE, serial. Maybe the other with.. ?
 

dJOS

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That's completely not true. PIO IDE works just fine (what XT-IDE uses). The only thing it accelerates on the stock system is floppy drive access. Nothing else get's sped-up. Even most network cards work just fine without DMA. Many early Ethernet adapters do not even support DMA (eg. NE1K/2K, Xircom, etc) and many more do not require it.

I had layed out a memory mapped Plus card similar to JR-IDE with the addition of two serial ports, but never could find a solution for the elevated 62 pin connector. The best path I found forward was, possibly, to make a two card set with a normal-ish height female connector downward and slightly taller male connector upward. One card with RAM, IDE, serial. Maybe the other with.. ?

yeah you are correct, I did a bit more reading on PIO etc after posting that.

the smart option for your idea imo would be to use a single 8-bit ISA slot on the PCB and have an optional riser-card to add a pair of ISA Slots in the horizontal plane.
 

dJOS

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That's completely not true. PIO IDE works just fine (what XT-IDE uses). The only thing it accelerates on the stock system is floppy drive access.

So just been doing some reading which seems to suggest that without the DMA controller you dont get the 16 color TGA graphics modes. If that is the case then it'd make Tandy gaming a bit pointless on an EX/HX.

EDIT: but then the original 1000 didnt have a DMA controller at all... Hmmm.
 
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Unknown_K

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The ISA adapter is of interest to me. Either an 8 bit SCSI card for an external drive or an 8 bit IDE card with a flash drive would be cool to have (assuming they fit).
 

Unknown_K

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So just been doing some reading which seems to suggest that without the DMA controller you dont get the 16 color TGA graphics modes. If that is the case then it'd make Tandy gaming a bit pointless on an EX/HX.

EDIT: but then the original 1000 didnt have a DMA controller at all... Hmmm.
I think the RAM upgrade card for the original 1000 added DMA (have to dig mine out someday).
 

dJOS

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The ISA adapter is of interest to me. Either an 8 bit SCSI card for an external drive or an 8 bit IDE card with a flash drive would be cool to have (assuming they fit).

Cheers.

I managed to buy way more ISA slots (50) than I'll likely ever need, the only thing I will need is more right angle headers and maybe another run of PCB's. :D

5mxbcerl.jpg
 
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