# AT&T UNIX PC recreated as open-source FPGA core for MiSTer

> **Key takeaway:** A complete FPGA softcore implementation of the 1985 AT&T UNIX PC workstation now runs on MiSTer-compatible hardware, with SystemVerilog/Verilog/VHDL sources available.

**Published:** 2026-11-08T15:00:46+00:00 
**Source:** Hackaday Hardware 
**Category:** open-hardware 
**Canonical URL:** https://fosswire.org/news/att-unix-pc-recreated-as-open-source-fpga-core-for-mister.html 

## Summary
Developer Hrvoje Cavrak has released an open-source FPGA recreation of the 1985 AT&T UNIX PC, a 10 MHz Motorola 68010 workstation that originally shipped with up to 4 MB of RAM. The softcore targets the MiSTer project ecosystem, meaning it synthesizes for any MiSTer-compatible FPGA board including the Terasic DE10-Nano with its Intel Cyclone V SoC.

The implementation requires an SDRAM add-on board for the DE10-Nano because the FPGA fabric side of the Cyclone V only exposes a fraction of the 4 MB needed by the softcore. The project mixes SystemVerilog, Verilog, and VHDL components, and some portions were developed with assistance from LLM coding tools. Users must source their own AT&T UNIX boot ROM and disk images, which remain under copyright.

## FPGA implementation and hardware requirements
- **CPU core:** Softcore recreation of the 10 MHz Motorola 68010 processor, the original UNIX PC's CPU.
- **Memory architecture:** Requires 4 MB of SDRAM, necessitating an SDRAM add-on board on the DE10-Nano since the Cyclone V FPGA side lacks sufficient onboard memory.
- **HDL sources:** Implementation spans three hardware description languages: SystemVerilog, Verilog, and VHDL.
- **Target platform:** Built for the MiSTer project, ensuring portability across MiSTer-compatible FPGA systems beyond just the DE10-Nano.
- **Development method:** Portions of the codebase were written and validated using LLM coding chatbots, with the author noting it remains a 'works on my MiSTer board' project.

## Why it matters
This project preserves a historically significant but rare UNIX workstation in open-source HDL, contributing to the growing MiSTer ecosystem of retro computing FPGA cores. For open hardware enthusiasts and preservationists, it offers accessible entry to a machine that has become financially unobtainable, though the copyright status of required ROM and disk images remains a practical barrier to immediate use.