# 6502 Model: reconstructing 65C02 cycle behavior

> 6502 Model reconstructs the 65C02 chip’s cycle behavior in Rust from traces of external buses recorded during execution on a physical chip. Contributors add programs and signed traces as failing cases, then implement behavior to match the observed cycles.

- Type: Case study
- Targets: Firmware
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-11-07
- Added to the catalog: 2026-11-09
- Original resource: <https://github.com/EmulationOnline/model_6502>
- Primary source: <https://github.com/EmulationOnline/model_6502/blob/bc7cf1457c4e9828288db9a9d8b4ff7daf251315/README.md>
- Catalog page: <https://awesomerea.org/resources/6502-model-case/>
- Record JSON: <https://awesomerea.org/resources/6502-model-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/6502-model-case/index.md)

## Requirements & limits

- **Prerequisites:** A physical 65C02 trace collected through ChipLab is used when adding behavior.
- **Limits:** Official instructions, timing details, flags, interrupts and unofficial instructions remain on the roadmap.
- **License:** BSD-3-Clause License.

## Primary sources

1. <https://github.com/EmulationOnline/model_6502/blob/bc7cf1457c4e9828288db9a9d8b4ff7daf251315/README.md>
2. <https://github.com/EmulationOnline/model_6502/blob/bc7cf1457c4e9828288db9a9d8b4ff7daf251315/passing_traces/README.md>

## More in Firmware and hardware

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## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.