Open-source simulator models Commodore 64 and ZX Spectrum at chip level
Salvatore Sanfilippo's open-source simulator replicates the physical hardware of the Commodore 64 and ZX Spectrum 48K, allowing users to remove chips, short pins, and observe electrical behavior rather than just running software.
Summary
A new open-source project by Salvatore Sanfilippo provides gate-level hardware simulation of two classic 8-bit computers: the Commodore 64 (ASSY 250407) and ZX Spectrum 48K (Board Issue 3B). Unlike traditional emulators that only replicate software execution, this simulator models individual chips, their connections, and electrical interactions. Users can manipulate the virtual motherboard—removing RAM, shorting pins, or modifying circuits—and see results on a virtual oscilloscope and monitor. The tool is available on GitHub and may help hobbyists diagnose hardware issues or test modifications before applying them to real machines.
How the simulator differs from emulation
- Simulates complete physical motherboard including all chips, pads, and sockets for the C64 ASSY 250407 and ZX Spectrum 48K Issue 3B
- Runs actual software on simulated hardware rather than abstracting the CPU and memory
- Provides three virtual instruments: video monitor, oscilloscope, and interactive motherboard view
- Allows physical manipulation: chip removal, pin shorting, connection modifications
- Models electrical consequences of hardware changes in real time
Why it matters
The tool lowers the barrier for hardware preservation and modification of vintage computers by removing the risk of destroying irreplaceable 1980s components. It may also serve as an educational resource for understanding how early microcomputers function at the electrical level.
Original reference: www.hackster.io →