nfc-forum-tags

#![no_std] Rust implementation of NFC Forum Tag Type operations.

This crate provides the command protocol, memory model, and NDEF access procedures for NFC Forum tags. It sits between the ISO 14443-3A activation layer and NDEF message parsing:

iso14443  (activation)  -->  nfc-forum-tags  (tag operations)  -->  ndef  (message parsing)

No dependency on either crate — raw &[u8] at both boundaries.

Functionalities

Shared

• TLV length encoding: 1-byte / 3-byte format used by all NFC Forum tag types
• Tag state: Initialized, ReadWrite, ReadOnly lifecycle states
• Access conditions: Granted, Denied, Proprietary, Rfu

Type 2 Tag (T2TOP 1.1)

• Commands: READ (0x30), WRITE (0xA2), SECTOR SELECT (0xC2)
• Capability Container: parsing, validation, version checking, access conditions
• TLV blocks: NULL, Lock Control, Memory Control, NDEF Message, Proprietary, Terminator
• Memory layout: static (64 bytes) and dynamic (multi-sector) structures, lock/reserved area tracking
• NDEF operations: detection, read, and write procedures via T2TReader

Usage

Implement the T2TTransceiver trait for your hardware, then use T2TReader to interact with the tag:

use nfc_forum_tags::type2::{T2TTransceiver, T2TReader};

// After ISO 14443-3A activation with a Type 2 Tag...
let mut reader = T2TReader::new(&mut my_transceiver);

// Read the Capability Container
let cc = reader.read_cc()?;

// Read NDEF message bytes
let ndef_bytes = reader.read_ndef()?;
// Pass to ndef crate: ndef::Message::try_from(&*ndef_bytes)

// Write NDEF message bytes
// let ndef_bytes = ndef_message.to_vec();
reader.write_ndef(&ndef_bytes)?;

Lower-level access is also available:

use nfc_forum_tags::type2::Command;

// Build commands manually
let cmd = Command::Read { block_no: 0x04 };
let wire_bytes = cmd.to_bytes(); // [0x30, 0x04] — CRC added by transceiver

// Parse responses
let answer = cmd.parse_answer(&response_bytes)?;

Features

Feature	Description
(default)	no_std with heapless fixed-capacity buffers
alloc	Use Vec instead of heapless::Vec
std	Implies alloc

License

GPL-3.0-or-later