Tool Open source
c64-hw-sim is a Commodore 64 motherboard simulator for the ASSY 250407 board. It models the board's 216 parts and 249 electrical nets at pin level, including the 6510, VIC-II, CIAs, SID, RAM, ROMs, logic chips, PLA equations, and discrete components. Users can lift or short individual pins, remove chips, open resistors or other connections, and observe the resulting monitor output, keyboard behavior, logic states, and oscilloscope signals. Its simulated netlist and chip behavior compute fault symptoms from the circuit rather than selecting predefined results; the simulator can also load .prg programs, run headlessly, apply timed faults, inspect bus contention, and record graphical output. It builds with make for macOS and Linux with X11 and OpenGL. The project is intended for studying C64 hardware and investigating repair hypotheses, not for playing games, and runs below real-time because every chip pin is simulated. Its models do not include the video output, SID filter, power supply, or dot-clock PLL, and the analog floating-line and power-fault values are approximations.
1 use taken from transcripts — each links to the moment in the video.
Lets you break a virtual Commodore 64 one pin at a time and watch what happens — pull a chip, ground a signal, or disconnect a resistor, then inspect the screen and oscilloscope. Symptoms emerge from simulated board connections and chip behavior, letting you explore repair hypotheses without touching a soldering iron.
1 in the library.