The Zilog Z80 has just turned 50 years old. This iconic 8-bit processor first went on sale in July 1976 and stayed in production for 48 years until Zilog, now a Littelfuse subsidiary, stopped accepting orders in June 2024. However, there’s an open-source replacement closer than ever to shipping in the chip’s original 40-pin DIP package thanks to community-funded fabrication.

The original Z80 packed 8,500 transistors on a 4μm process and typically ran at 2.5 MHz, with later CMOS variants reaching 20 MHz. Binary compatibility with the Intel 8080 let it absorb the existing CP/M software base, with an on-die DRAM refresh counter that cut the number of support chips a system needed. Development of working prototypes cost roughly $400,000 against $500,000 in funding from Exxon, per the Computer History Museum.

The chip powered the ZX Spectrum, TRS-80, MSX machines, Nintendo’s Game Boy, Sega’s Master System, the Pac-Man arcade cabinet, and Texas Instruments’ graphing calculators, then shipped in industrial controllers for decades after home computing moved on to more powerful successors. Zilog’s end-of-life notice, dated April 15, 2024, told customers its wafer foundry was discontinuing support for the Z84C00 family, and last-time-buy orders closed that June.

Renaldas Zioma’s FOSS Z80 project, launched shortly after the end-of-life notice, now has working silicon. The first version, fabbed on SkyWater’s 130nm node through Tiny Tapeout 7 on a die of just 0.064mm2, has been confirmed as functional via the project’s GitHub repository. A QFN64 version with all 40 pins exposed followed on the Efabless CI2406 shuttle, two further runs then went through IHP’s 130nm process, and the current run targets the classic DIP40 form factor using chip-on-board assembly on GlobalFoundries’ 180nm GF180MCU node via Wafer.Space. The end goal here is to fab a drop-in replacement for machines like the ZX Spectrum and RC2014 kits.

The design is built around Guy Hutchison’s TV80 Verilog core, and the project’s Tiny Tapeout page says the 130nm CMOS implementation should support clocks up to 50 MHz, against 4 MHz for the original NMOS part.

https://github.com/rejunity/z80-open-silicon

The FHWA has not publicly announced or explained the decision to cut the list of safety strategies from 28 items to the current total of 23.

• Before: https://web.archive.org/web/20260101053236/https://highways.dot.gov/safety/proven-safety-countermeasures
• After: https://web.archive.org/web/20260717205718/https://highways.dot.gov/safety/proven-safety-countermeasures

What they seem to have in common is:

• Way more posts than comments.
• Almost exclusively posting news articles.
• The vast majority of the articles are critical of Russia or China.
• Virtually always posting to the same few communities. Often there’s overlap in the communities the accounts target.
• Consistent weekly output.

FYI, @haui@lemmygrad.ml, you had this to say back in June on !europe@lemmy.dbzer0.com, before the post was removed by a mod:

OP is one of their propagandists from the looks of it. Please look at the post history and report if you see a pattern.

[Edited to update links for thelucky8@beehaw.org and and the archived post]
[Edited to add new account, tardigrada@scribe.disroot.org]