FCF Viewer is a minimal FeliCa utility that reads the FCF (FeliCa Common Format) area of a card and prints the result to the console.
The CLI logic lives in fcf_viewer/cli.py and is also reused by the Tkinter GUI for a live view of the same data.

The reader performs a raw FeliCa polling against system code 0xFE00 and decodes only the areas that cli.py touches:

If the card does not expose the FCF services, the tool prints the same error strings defined in cli.py.

• Python 3.14+
• Poetry 1.8+
• A FeliCa reader supported by nfcpy (e.g. Sony RC-S380)
• System drivers that allow python to access the USB device

poetry install

1. Connect your FeliCa reader.
2. Run the entry point while the card is touching the reader.

poetry run fcf-viewer

The CLI prints three sections in Japanese:

• カード識別: IDm / PMm
• 基本情報: the nine fields listed above
• FCF-UN: value from the dedicated block, or an error if the card does not support it

All decoding is handled inside FcfTagReporter (see fcf_viewer/cli.py).

poetry run fcf-viewer-gui

The GUI continuously polls the reader, mirrors the CLI decoding, and updates the on-screen values (IDm, PMm, 基本情報, FCF-UN).
Status messages are shown for unsupported cards, read errors, or reader initialization failures.

• このカードは FCF に対応していません: the service blocks in cli.py are unavailable on the card. Try a different card.
• NFC リーダーを初期化できません: the USB device is busy or the required driver/libusb stack is missing.
• Non-FeliCa tags are ignored; keep the supported card on the reader until the read completes.

• Format code with poetry run black fcf_viewer
• The CLI and GUI both rely on nfcpy, so desktop testing requires a compatible reader. Use unit tests or dependency injection for offline development when possible.

MIT

Copyright (c) 2025 KIRISHIKI Yudai