TI99/4A KEYBOARD ADAPTATION

Discussions about Sinclair ZX80 and ZX81 Hardware
User avatar
gammaray
Posts: 534
Joined: Sun Apr 17, 2016 2:44 am
Location: Texas

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
(2.62 MiB) Downloaded 32 times
I have not found any logic errors on your board yet but still not done...
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

User avatar
gammaray
Posts: 534
Joined: Sun Apr 17, 2016 2:44 am
Location: Texas

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.
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

User avatar
gammaray
Posts: 534
Joined: Sun Apr 17, 2016 2:44 am
Location: Texas

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.
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

User avatar
gammaray
Posts: 534
Joined: Sun Apr 17, 2016 2:44 am
Location: Texas

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?
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

User avatar
1024MAK
Posts: 2152
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

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

User avatar
gammaray
Posts: 534
Joined: Sun Apr 17, 2016 2:44 am
Location: Texas

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...
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

User avatar
gammaray
Posts: 534
Joined: Sun Apr 17, 2016 2:44 am
Location: Texas

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.
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

User avatar
gammaray
Posts: 534
Joined: Sun Apr 17, 2016 2:44 am
Location: Texas

Re: TI99/4A KEYBOARD ADAPTATION

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

WIREDUP.png
WIREDUP.png (8.38 KiB) Viewed 639 times
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

soviet9922
Posts: 10
Joined: Thu Feb 08, 2018 2:00 pm

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.

User avatar
gammaray
Posts: 534
Joined: Sun Apr 17, 2016 2:44 am
Location: Texas

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)
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

Post Reply