Help Requested for Project

Charlie

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Hi Chaps,
I know, I've been rather anonymous for a while & now I pop up asking for help. :oops:

So here it is - I have a project in mind that may be of interest to modders of retro computers in general but I've hit a snag:

Some chips I require are manufactured in the US by Sprintek.
The Good:
I have to say they've been very helpful and will happily supply in small numbers.
The Bad:
Postage within the US seems to be $0.00, but to the UK it's about £55.00 for three chips!
Three Low profile QFN 56 pin packages: 8x8mm - I assume they intend to lay on a private jet and armed guards!

At these prices the project is dead in the water, I'll never be able to make boards cheap enough for others to afford.

So, my request is to any US members - I'd happily send the money up front if anyone feels they could arrange MUCH more reasonable postage to the UK.

Thank you. :)


Didn't I mention what the project is? Ok:

Some peeps may be aware of interfaces like the >I-PAC<. A way of interfacing arcade gaming pads, etc to an x86 motherboard...
...to help turn your MAME-PC into a proper home-gaming cabinet.

Now, that's all well and good but what if like me you're a bit of a case-modder?
The hardest (most tediously frustrating) part is getting a retro-keyboard to interface with your 'modern' USB/PS2 equipped motherboard...

...The 'standard' method is to gut a PC keyboard like >this< one, then work out how it's matrix is arranged, then work out the matrix for your retro-keyboard, then see if they match.
Usually you end up completely re-wiring said retro-keyboard to match, then the interface chip from said 'new' keyboard can be hacked in and hurrah! You have a working retro-keyboard that will interface with your USB/PS2 equipped system.

-Amazingly tedious and fiddly process-​

Every time I do this I promise myself that I'll never do it again. Surely there must be a better way?
Well, what would be nice is there was a programmable keyboard interface in the same vein as the I-PAC. You could just plug your retro-keyboard into that, program the interface to suit, and Bob's your significant other.

I've only ever found one, it's too big AND amazingly expensive. No, arcade-type interfaces won't do for this. Yes, there is such an interface for Amiga keyboards but excellent though it is, it's too big and not user-programmable.

So my plan is to make such an interface myself based around one of Sprintek's chips.
-The board will hopefully be less than 3x2cm
-Covered in pin-headers and a USB port
-It will be fully customisable in software
-Will only need a USB-equipped PC to program it
-Will interface via PS2 or USB
-Should be able to handle Row/Column of 8x20
-Can handle a mouse if required
-Could handle digital joypads if required
-Will have LED headers for Caps-Lock etc
-Will cost in the range of £20.00 to make @ home*
*Assuming I can do something about the shipping charges.

So who'd be interested?
 

Merlin

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@ Charlie

I realise that I may get killed for asking this in relation to your uber-secret project :LOL:, but what type of chips (model No.) are we talking about here..? Are they only available in the US?
 

Charlie

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Hi Merlin,
Here's a link for you >SK5100/SK5101<

Quite frankly (as I'm sure you know) I'm no uber-electronics whiz. The software is already available, there's a schematic already available.

'All' I'm intending to do is simplify their own take on this board down to the bare minimum for size and cost, then solder up my own home-made PCB's.

Yes, soldering a QFN package isn't so easy but I've reworked dead SIMMs successfully and done some surface mount stuff so it should be achievable for me.
 
Last edited:

Muzer

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Which keyboards currently have "drivers"?
 

Merlin

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@ Muzer

I think Charlie's idea is that you can map pretty much any keyboard, so that you can have PC-based Amiga/Spectrum/C64 etc that uses the original keyboard, mapped correctly.
 

Charlie

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Ah, good question - no drivers required. The tentatively planed board will handle all the hard stuff itself.

-If using PS/2, any motherboard with such an interface will work.
-If USB, as long as your chosen OS has a USB keyboard driver it will work,
or if your BIOS will fake PS/2 over USB...

The planned process will be:
-Plug interface into retro keyboard
-Plug interface into PC (via USB)
-Fire up the programming software (Windows required)
-Fiddle away with retro keyboard until you're happy
-Unplug the USB from the PC
-Use either said USB or PS2 port to plug your newly programmed retro-keyboard into the intended motherboard.

Done!

Should work for any keyboard that uses a matrix to generate characters. I'm not 100% sure but it should even work with a multiplexed keyboard like the one out of the Oric Atmos - my current case-modding project that got me thinking.
There's no reason why you couldn't use spare capacity to interface digital joypads, though one would have to take care with ghosting of keys.
And you get a mouse port for 'free' if using USB.

*Edit*
Merlin's put it far more succinctly than me.
 

Zetr0

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@Charlie

my friend, you should look into PIC16 programming its very simple and will provide a good return on your effort.

the chips are VERY cheap including postage you could get a couple that would be under £4 - they could easly provide an 8 - 20 matrix as well as convert it to PS2 protocol

theres lots of sources on the net, I plan to do this with my Spectrum 128 +2 / DivIDE combo.
 

Merlin

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So, if I understand this correctly, you could hack a small PC motherboard inside a retro case and use the original machines keyboard, so that the hacked project looks and feels like the real thing?

Cool!
 

Muzer

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Ah, I misunderstood. Presumably you'd have to rip the keyboard apart - it's not at a stage where it can adapt to suit any keyboard's proprietary serial bus for sending the actual data through a connector.
 

Charlie

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Yep, that's about the size of it:

-Gut retro computer
-Fit modern mobo
-Interface the original keyboard to said mobo
->Retro goodness.

Usually you do that by using the guts of a PS/2 / USB keyboard for the PS/2 / USB end and mod the wiring of the retro-keyboard to suit...
...amazingly tedious and fiddly.

@Zetr0:
A good plan indeed - thank you. Some day I really will have to get into this.
The reason for the above plan is so I can potentially make boards that anyone can use to set up for their own project.

@Merlin:
Exactly!

@Muzer:
If the keyboard in question outputs a matrix then no mods should be needed, just plug it in. (Most retro keyboards?)
If it uses some kind of proprietary interface then, yes, some hackery will be needed to get back to the actual row/column matrix - does any keyboard ultimately use any other method?
Even so, it's still going to be much easier than doing it yourself from scratch.

Thanks for the interest chaps. :)
 

Muzer

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If it uses some kind of proprietary interface then, yes, some hackery will be needed to get back to the actual row/column matrix - does any keyboard ultimately use any other method?
Even so, it's still going to be much easier than doing it yourself from scratch.

I assume most external keyboards will use proprietary interfaces - most internal ones as you say would probably just connect directly to the motherboard.
 

rkauer

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An Amiga keyboard have ready-made solution: the Lyrah/Keyra. Other machines: don't know.
 

Charlie

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An Amiga keyboard have ready-made solution: the Lyrah/Keyra. Other machines: don't know.

And very good they are too...


I'm glad this has sparked some interest. Back to my request:

Would any US residents be prepared to talk about cheaper ways of getting these chips across the Atlantic?
or
Can anyone point me in the direction of a local source?
or
A similar-speced chip, locally?
or
A better plan?

I rather like Zetr0's idea, though if I'm going to the trouble I want to make something others can use themselves.

P.S.
@Muzer:
True, but if this idea gets anywhere it may prove useful for external retro-keyboards...
...crack the keyboard, pull out the old interface board, replace with programmable board + PS/2 / USB lead, job done. Ok, some setting-up required.
 
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