How to build your own ZX80/ZX81 (2019)
searle.x10host.com
searle.x10host.com
Now we have GPUs which can do all sorts of things, but a graphics coprocessor for an 8-bit machine is a nice addition.
Same here. Lived in India, my fathers' friend (based in the UK) gifted him a ZX Spectrum. I was hooked from the day I typed 10 PRINT "myname" on it. Taught myself Z80 assembly, just from the appendix in the Spectrum programmers manual that listed the opcode encodings and mnemonics (mostly just guessing what the opcode did from the mnemonic) - at around 10 years old, I could hand-write and hand-encode the assembly code without needing to lookup the opcode encodings.
I was 6 years old at the time.
Completely determined the trajectory of my life/career.
ATX-80 – ZX-80 computer clone with ATmega8 processor https://news.ycombinator.com/item?id=29569523
This is not an exact replica like the one linked above, but an ingenious DIY re-creation built with modern parts, including just two ICs, with an ATMega8 processor instead of a Z80. Not an emulation, but a complete rewrite of the original Z80 monitor and BASIC interpreter in AVR assembly.
https://microcorelabs.wordpress.com
Cycle-accurate emulation with appropriate electrical connections and pinout make it a fully compatible software implementation of the original hardware CPU.
In the early 1980's, the ZX81 was the poverty specification machine. Rich kids had their fancy BBC Micro Model B, Atari 800, C64 or other proper machine, in a heated study room, with dependable electricity and other niceties.
Working class kids had the ZX Spectrum, Vic 20 or, if their grandma got the memo wrong, something like a Dragon 32 or Oric 1, which counted them out of the games swapping world of the playground.
Poor kids had the ZX81 and really poor kids had the ZX81 that you had to make yourself, the kit-form version that was £20 cheaper. Or failing that, a hand-me-down ZX80 or a Microbrain thing with just a hex keypad and a few LEDs.
Hence, although it might seem a great idea to make a ZX81 nowadays, for the British poor kid, it comes with the stigma, the reminder that it was you that had the kit-form ZX81, with no heated study room, and no 16K of RAM.
Learned BASIC, assembly, a bit of Forth on that thing, and as I grew up branched out to C64 and Apple II’s and PCs, eventually became a professional developer.
It all was enabled by the TS 1000 (and by extension the creation of the ZX-80 and ZX-81).
To steal a cheesy movie quote, that $99.95 little slab of plastic and chips changed my stars.
Building a ZX81 from a kit sounds highly educational - not to mention learning how to wring the last bit of performance and functionality out of a tiny system with minimal RAM.
Original Elite was tied into BBC Micro specific things such as how the display worked, BBC Elite had a split display mode with black and white high-resolution at the top (Mode zero) and four colour 'mode two' at the bottom, for the 'dashboard'.
The AY-3-8912 sound card in the BBC Micro was also part of it. On the Spectrum there was just the beeper, and the display was not capable of those clever modes that Braben/Bell amazed everyone with.
I will explain the problem with rutabaga...
In northern Europe, nobody wants to eat rutabaga (swede) because that was what people ate when there was nothing else to eat, it was poverty food, best fed to the animals. Actually swede is a fine vegetable, I eat swede all the time, but I never went through a famine.
With the kit form ZX81, imagine being an eleven year old in the cold with a soldering iron and a Sinclair kit-form ZX81, knowing that the most you will get out of it is 1K Chess, when your friends are playing JetSet Willy on a Spectrum or better, no need for this wholesome electronics stuff, just mainlining the good stuff, as in games.
We were just kidding ourselves about microcomputers and programming, think of your peers and how many of them ever had working code to share with you. It never happened.
Hmm, I could see why the ZX81 kit would be educational but perhaps not as exciting as the ZX Spectrum with its color graphics and game library.
I'm not an expert on the Spectrum, but it seems like a very capable machine, with a lot of good games, some great contemporary books and magazines, and many fans here on HN.
It looks like later models featured a capable sound chip. And it had a Z-80 CPU, allowing the +3 to run CP/M natively.