TI99/4A KEYBOARD ADAPTATION
Re: TI99/4A KEYBOARD ADAPTATION
P5 AND 2Y0 ARE NOT USED
This is what I came up with. Did you? Combined with the other table is fully decoded.
I have not found any logic errors on your board yet but still not done...
This is what I came up with. Did you? Combined with the other table is fully decoded.
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
Re: TI99/4A KEYBOARD ADAPTATION
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
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
Re: TI99/4A KEYBOARD ADAPTATION
Do we need a driver board to repeat(amplify) the signals?
https://sinclairzxworld.com/viewtopic. ... oard#p2046
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
Re: TI99/4A KEYBOARD ADAPTATION
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
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Re: TI99/4A KEYBOARD ADAPTATION
Not if the wiring is kept as short as possible.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
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
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: TI99/4A KEYBOARD ADAPTATION
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
Re: TI99/4A KEYBOARD ADAPTATION
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
Re: TI99/4A KEYBOARD ADAPTATION
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
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Re: TI99/4A KEYBOARD ADAPTATION
Thanks for the diagrams this last one is really help full going to give it a shot tonight.
Re: TI99/4A KEYBOARD ADAPTATION
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)
(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