TI99/4A KEYBOARD ADAPTATION

Discussions about Sinclair ZX80 and ZX81 Hardware
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gammaray
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Re: TI99/4A KEYBOARD ADAPTATION

Post by gammaray » Tue Feb 20, 2018 2:41 am

P5 AND 2Y0 ARE NOT USED

This is what I came up with. Did you? Combined with the other table is fully decoded.
TI PINOUT.jpg
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I have not found any logic errors on your board yet but still not done...
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

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gammaray
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Re: TI99/4A KEYBOARD ADAPTATION

Post by gammaray » Tue Feb 20, 2018 4:22 am

Check to see if you have 2Y1 shorted with 2Y2 at "<". Following the traces it looks like it. I cant see diagram well enough to be sure. Let me know.

UPDATE: I see the "2y2" trace cut in photo from a different angle. Still looking.


One thing one hasve to decide first I guess is do you want all the keys to stay in position like normal typewriter layout.
The second is whether you want to use the "extended keys" available or have a ZX keyboard layout.

I chose to leave keys in place, but moving the caps is also a way.viewtopic.php?f=7&t=2771#p29847

Charles :)
Last edited by gammaray on Sat Mar 10, 2018 5:12 am, edited 1 time in total.
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

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gammaray
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Re: TI99/4A KEYBOARD ADAPTATION

Post by gammaray » Tue Feb 20, 2018 5:48 pm

Do we need a driver board to repeat(amplify) the signals?
https://sinclairzxworld.com/viewtopic. ... oard#p2046
Last edited by gammaray on Tue Feb 20, 2018 6:59 pm, edited 1 time in total.
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

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gammaray
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Re: TI99/4A KEYBOARD ADAPTATION

Post by gammaray » Tue Feb 20, 2018 6:58 pm

TIKEY WIRE CROSSOVER_2018-02-20_11-55-55.png
is this correct?
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

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1024MAK
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Re: TI99/4A KEYBOARD ADAPTATION

Post by 1024MAK » Tue Feb 20, 2018 7:09 pm

gammaray wrote:
Tue Feb 20, 2018 5:48 pm
Do we need a driver board to repeat(amplify) the signals?
https://sinclairzxworld.com/viewtopic. ... oard#p2046
Not if the wiring is kept as short as possible.

If you do want longer wiring, or want to use a multicore cable, then it's the address lines that need buffering. On the Harlequin, transistors are used.

Mark

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gammaray
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Re: TI99/4A KEYBOARD ADAPTATION

Post by gammaray » Tue Feb 20, 2018 7:35 pm

Danmoore used 12" ribbon! He is pushing the envelope. Not really, I would expect 6' to be a problem. I could test it...
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

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gammaray
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Re: TI99/4A KEYBOARD ADAPTATION

Post by gammaray » Wed Feb 21, 2018 2:13 am

D3 AND D4 should be crossed for Speccy operation so DPDT switch should work.
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

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gammaray
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Re: TI99/4A KEYBOARD ADAPTATION

Post by gammaray » Fri Mar 09, 2018 11:26 pm

WIREDUP.png
WIREDUP.png (8.38 KiB) Viewed 363 times
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

soviet9922
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Re: TI99/4A KEYBOARD ADAPTATION

Post by soviet9922 » Wed Mar 14, 2018 6:00 pm

Thanks for the diagrams :) this last one is really help full going to give it a shot tonight.

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gammaray
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Re: TI99/4A KEYBOARD ADAPTATION

Post by gammaray » Wed Mar 14, 2018 6:56 pm

I am making a PCB to be able to connect ZX81 keyboard matrix directly into keyboard in the TI99 case and mount main board with a modified TAZ project... not there yet. Need to check pinout again before I order. TAZ 1.0 being layed out.

(Project still requires trace modification cuts to your specification, but eliminates another cable)
Finish what you start. Truth is over the mountaintop or six feet under.
4 x TS1000, 2 x TS1500 , 2 x timex 2040 printer, 1/2 x timex 2020 cassette deck, ZXPAND+AY, ZeddyNET, ZXBlast..., unfinished Spectrum...Still no life!

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