GAL JED Simulator

Upload a GAL16V8 / GAL20V8 / GAL22V10 (or ATF-compatible) JED and interact with the decoded logic as if it were on a breadboard. The JED supplies the logic; an optional .pin file supplies human-readable pin names.

About

This tool simulates GAL16V8, GAL20V8, and GAL22V10 fuse maps (JED files) interactively, letting you toggle inputs and pulse the clock to see how the decoded logic drives each output pin. Created to help validate PAL/GAL logic before you programme the chip.

Load a JED file (with an optional .pin file for readable pin names), or click "Load example" to try a built-in demo. Tip: press Space to pulse the clock.

Everything runs locally in your browser - nothing you upload is sent anywhere.

Fuse-map details for GAL16V8, GAL20V8, and GAL22V10 verified using GALasm as reference, cross-checked against the Lattice/Atmel datasheets.

Created by Derek Robson.
Support me at ko-fi
Open source - github.com/robsonde/gal_sim
Another Asinine Project from asinine-labs.org

Version 1.0 - 18/08/2026
Device: — Fuses: — Signature: — Logic terms: —

Virtual breadboard

● LED = pin output ◉ switch = external input CLK switch (low→high) or Pulse button updates registered outputs

Decoded logic

Load a JED file.