Add card detection

pn532/src/lib.rs

@@ -0,0 +1,59 @@
+#![no_std]
+#![forbid(unsafe_code)]
+
+//! A `no_std` [`embedded-hal`] driver for the NXP PN532 NFC controller over I2C.
+//!
+//! This crate is a Rust port of the well-known
+//! [Adafruit/Seeed PN532 Arduino library](https://github.com/elechouse/PN532),
+//! targeting the I2C interface (the most common breakout-board wiring).
+//!
+//! The driver is transport-agnostic via the [`Interface`] trait; [`I2cInterface`]
+//! provides the I2C implementation on top of a blocking `embedded_hal::i2c::I2c`
+//! bus plus a `embedded_hal::delay::DelayNs` delay source.
+//!
+//! # Example
+//!
+//! ```ignore
+//! use embedded_hal::delay::DelayNs;
+//! use pn532::{BaudRate, I2cInterface, Pn532};
+//!
+//! # struct Delay;
+//! # impl DelayNs for Delay { fn delay_ns(&mut self, _: u32) {} }
+//! #
+//! # fn demo<I2C>(i2c: I2C, delay: Delay)
+//! # where I2C: embedded_hal::i2c::I2c
+//! # {
+//! let mut nfc = Pn532::new(I2cInterface::new(i2c, delay));
+//! nfc.begin().unwrap();
+//! nfc.sam_config().unwrap();
+//!
+//! let uid = nfc
+//!     .read_passive_target_id(BaudRate::ISO14443A106kbps, 1000)
+//!     .unwrap();
+//! if let Some(uid) = uid {
+//!     // uid.bytes[..uid.len as usize] contains the card UID
+//! }
+//! # }
+//! ```
+//!
+//! # Limitations
+//!
+//! * Responses are limited to 64 bytes, matching the PN532's internal packet
+//!   buffer (this also constrains multi-block FeliCa reads).
+//! * The I2C interface is blocking and uses busy-wait polling for the PN532's
+//!   "ready" flag, mirroring the original Arduino implementation.
+
+pub mod commands;
+pub mod error;
+pub mod felica;
+pub mod interface;
+
+pub(crate) mod driver;
+pub mod tg;
+pub mod mifare;
+pub mod iso14443a;
+
+pub use commands::BaudRate;
+pub use driver::{FelicaPollingResponse, Pn532, TargetInitStatus, Uid};
+pub use error::Error;
+pub use interface::{I2cInterface, Interface, NoIrq, NoReset};