{
  "added_at": "2026-11-08",
  "additional_evidence_urls": [
    "https://github.com/maddenste/Chouchin-CH899-Firmware/blob/aaf649283633ce3a081879c90a691af2897b1e1b/README.md",
    "https://github.com/maddenste/Chouchin-CH899-Firmware/blob/aaf649283633ce3a081879c90a691af2897b1e1b/docs/REVERSE_ENGINEERING.md"
  ],
  "category": "reconstruction-cases",
  "class": "hardware",
  "description_en": "CH899 firmware research reconstructs the UART exchange between the clock's MM32 movement controller and ESP8285 Wi-Fi module. It records wake, time and reset messages from stock behavior and implements replacement ESP firmware that adds Wi-Fi setup and timekeeping options while retaining the original movement controller.",
  "description_zh": "CH899 固件研究还原时钟的 MM32 走针控制器与 ESP8285 Wi-Fi 模块之间的 UART 通信。项目记录原固件的唤醒、报时和重置消息，并实现带有 Wi-Fi 配网及校时选项的 ESP 替代固件，保留原走针控制器。",
  "entry_url": "https://awesomerea.org/resources/chouchin-ch899-firmware-case/",
  "entry_url_zh": "https://awesomerea.org/zh/resources/chouchin-ch899-firmware-case/",
  "evidence_class": 1,
  "evidence_status": "observed",
  "evidence_url": "https://github.com/maddenste/Chouchin-CH899-Firmware/blob/aaf649283633ce3a081879c90a691af2897b1e1b/docs/PROTOCOL.md",
  "group": "cases",
  "id": "chouchin-ch899-firmware-case",
  "json_url": "https://awesomerea.org/resources/chouchin-ch899-firmware-case/record.json",
  "kind": "case-study",
  "markdown_url": "https://awesomerea.org/resources/chouchin-ch899-firmware-case/index.md",
  "markdown_url_zh": "https://awesomerea.org/zh/resources/chouchin-ch899-firmware-case/index.md",
  "name": "CH899: reconstructing the clock's MM32–ESP exchange",
  "name_zh": "CH899：还原时钟的 MM32–ESP 通信",
  "preview_kind": "image",
  "preview_url": "https://awesomerea.org/previews/chouchin-ch899-firmware-case.jpg",
  "record_type": "resource",
  "relationship": "independent-reconstruction",
  "requirement_facets": [
    "prerequisites",
    "scope",
    "license"
  ],
  "requirements": [
    "The older CH899 clock board whose main chip is marked MM32.",
    "Replacement applies to the ESP8285 Wi-Fi firmware; the MM32 movement firmware remains in place.",
    "GPL-3.0-or-later license."
  ],
  "requirements_zh": [
    "需要主芯片标有 MM32 的旧版 CH899 时钟电路板。",
    "仅替换 ESP8285 Wi-Fi 固件；MM32 走针固件保持原样。",
    "采用 GPL-3.0-or-later 许可证。"
  ],
  "scope": "partial",
  "targets": [
    "firmware",
    "protocol"
  ],
  "url": "https://github.com/maddenste/Chouchin-CH899-Firmware",
  "verification": "source-reviewed",
  "verified_at": "2026-11-06"
}