ZX81 ULA-in-a-CPLD

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
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Andy Rea
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Re: ZX81 ULA-in-a-CPLD

Post by Andy Rea » Sat Mar 10, 2018 12:13 am

McKlaud wrote:
Fri Mar 09, 2018 11:54 pm
Andy, I am glad reading your post. :) You are Master Yoda of ZX81 ULA, I am just newbie in this world. BTW Could you correct pictures, I can't see them.
see if it images show now

regards
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

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1024MAK
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Re: ZX81 ULA-in-a-CPLD

Post by 1024MAK » Sat Mar 10, 2018 12:17 am

Images now showing for me :ugeek:

Mark

McKlaud
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Re: ZX81 ULA-in-a-CPLD

Post by McKlaud » Sat Mar 10, 2018 12:22 am

Andy Rea wrote:
Sat Mar 10, 2018 12:13 am
McKlaud wrote:
Fri Mar 09, 2018 11:54 pm
Andy, I am glad reading your post. :) You are Master Yoda of ZX81 ULA, I am just newbie in this world. BTW Could you correct pictures, I can't see them.
see if it images show now

regards
Thanks a lot, now they are perfectly visible :)
Claudius
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gammaray
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Re: ZX81 ULA-in-a-CPLD

Post by gammaray » Sat Mar 10, 2018 12:34 am

Estimated power usage...really low?
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: ZX81 ULA-in-a-CPLD

Post by McKlaud » Sat Mar 10, 2018 12:55 am

In my case the CPLD is not even warm. The hottest part in my testing board is the ROM chip now. The power consumption is roughly 250mA, but I have also got a 16KB SRAM chip on this board. I think I could go even lower if the 7805 were replaced with any decent DC-DC converter.
Last edited by McKlaud on Sat Mar 10, 2018 1:02 am, edited 1 time in total.
Claudius
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gammaray
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Re: ZX81 ULA-in-a-CPLD

Post by gammaray » Sat Mar 10, 2018 12:57 am

:P :D :shock: ;)
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: ZX81 ULA-in-a-CPLD

Post by McKlaud » Sat Mar 10, 2018 1:06 am

First "K" seen on the screen, but some issues with stability and timings.
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zULA_prot_04.jpg
Claudius
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RetroTechie
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Re: ZX81 ULA-in-a-CPLD

Post by RetroTechie » Sat Mar 10, 2018 1:30 am

@McKlaud and Andy: NICE!!! :) Especially Andy's 45-degree placement of the CPLD is likely how I'd have done it myself.
McKlaud wrote:The power consumption is roughly 250mA, but I have also got a 16KB SRAM chip on this board. I think I could go even lower if the 7805 were replaced with any decent DC-DC converter.
Indeed. My ZX81 pulls around 800 mW, that is DC-DC converter included. Some 600 mW (120 mA @5V) if powered with 5V directly. CMOS Z80 and CPLD macrocells in low-power mode are the biggest quick/easy savings afaik.

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Andy Rea
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Re: ZX81 ULA-in-a-CPLD

Post by Andy Rea » Sat Mar 10, 2018 1:55 am

Top job Claudius, it's a very rewarding feeling when you get an image for the first time.

@retrotechie, cheers man, the driving factors for that kind of placement was size wanted it basically the same size as the socket and i really wanted all 40 pins through hole instead of the central ones been smd It does mean that i lose 4 pins as the corner ones are so close to the through holes that they are doubled up. But plenty of pins anyway.

Regards Andy
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

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Re: ZX81 ULA-in-a-CPLD

Post by Moggy » Sat Mar 10, 2018 3:41 pm

Well done to all concerned.

Look forward to seeing these on Sell My Retro. :D

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