• RFID
  • Intermediate
  • 3 min
  • Serial CLI

Recipe · Intermediate · RFID

How to write an NFC tag page

Use RFID mode with a PN532 module to write lab data to an NTAG or Ultralight page.

RFID reader communicating with a contactless tag.
Start with read-only checks, then move to write, replay or automation only when the setup is understood.
Step 1

Commands

Use the shortest command path that matches the documented firmware workflow. When a mode needs setup, follow the prompts shown on first entry.

Result

What it means

The command path is working when the target responds and the firmware prints the expected menu, status or captured data.

Troubleshooting

  • Re-enter the mode setup when pins or peripherals are not already initialized.
  • Check common ground and target voltage before blaming software.
  • Prefer Serial CLI for long captures or high-volume output.
  • Repeat the read or capture to confirm stability.

Next steps

  • Save the output in your project notes.
  • Compare the result with the full wiki page for mode-specific details.
  • Create a shorter alias if you repeat this workflow often.

NTAG page write FAQ

Why are NTAG writes page-based?

NTAG and Ultralight-style tags use small 4-byte pages. The page index matters, and writing the wrong page can alter user data, lock settings or tag metadata.

How should I test a first write?

Use a disposable NTAG lab tag and write a harmless 4-byte pattern to a user page, then read the tag again to confirm the exact page changed as expected.

Can every NFC tag be written this way?

No. The tag must be a supported family, writable, unlocked and close enough to the PN532 antenna. Some tags are read-only, locked or require a different workflow.

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