Add card detection

pn532/src/iso14443a/mod.rs

@@ -0,0 +1,91 @@
+use crate::{BaudRate, Error, Interface, Pn532, Uid};
+use crate::commands::{PN532_COMMAND_INDATAEXCHANGE, PN532_COMMAND_INLISTPASSIVETARGET, PN532_COMMAND_INRELEASE};
+use crate::error::StatusCode;
+
+impl<B: Interface> Pn532<B> {
+    /// Wait for an ISO14443A target and read its UID.
+    ///
+    /// Returns `Ok(None)` when no card appears within `timeout_ms` milliseconds.
+    pub fn read_passive_target_id(
+        &mut self,
+        card_baudrate: BaudRate,
+        timeout_ms: u16,
+    ) -> Result<Option<Uid>, Error<B::TransportError>> {
+        self.buffer[0] = PN532_COMMAND_INLISTPASSIVETARGET;
+        self.buffer[1] = 1;
+        self.buffer[2] = card_baudrate.into();
+        self.send(3)?;
+
+        match self.read_timeout(timeout_ms) {
+            Err(Error::Timeout) => return Ok(None),
+            Err(e) => return Err(e),
+            Ok(_) => {}
+        }
+
+        if self.buffer[0] != 1 {
+            return Ok(None);
+        }
+
+        let uid_len = self.buffer[5];
+        if uid_len > 7 {
+            return Err(Error::InvalidFrame);
+        }
+
+        let mut bytes = [0u8; 7];
+        bytes[..uid_len as usize].copy_from_slice(&self.buffer[6..6 + uid_len as usize]);
+
+        Ok(Some(Uid { bytes: heapless::Vec::from_array(bytes) }))
+    }
+
+    /// In-list a passive target (used before [`Self::in_data_exchange`]).
+    pub fn in_list_passive_target(&mut self) -> Result<bool, Error<B::TransportError>> {
+        self.buffer[0] = PN532_COMMAND_INLISTPASSIVETARGET;
+        self.buffer[1] = 1;
+        self.buffer[2] = 0;
+        self.send(3)?;
+
+        match self.read_timeout(30_000) {
+            Err(Error::Timeout) => return Ok(false),
+            Err(e) => return Err(e),
+            Ok(_) => {}
+        }
+
+        if self.buffer[0] != 1 {
+            return Ok(false);
+        }
+        self.in_listed_tag = self.buffer[1];
+        Ok(true)
+    }
+
+    /// Exchange data with the currently in-listed peer.
+    ///
+    /// Returns the number of bytes written to `response`. The response buffer
+    /// is limited to 64 bytes.
+    pub fn in_data_exchange(
+        &mut self,
+        send: &[u8],
+        response: &mut [u8],
+    ) -> Result<usize, Error<B::TransportError>> {
+        self.buffer[0] = PN532_COMMAND_INDATAEXCHANGE;
+        self.buffer[1] = self.in_listed_tag;
+        self.send_with_body(2, send)?;
+
+        let len = self.read_timeout(1000)?;
+        if len == 0 || (self.buffer[0] & 0x3F) != 0 {
+            return Err(Error::Status(StatusCode::from_repr(self.buffer[0] & 0x3F).unwrap()));
+        }
+
+        let data_len = len - 1;
+        let copy_len = data_len.min(response.len());
+        response[..copy_len].copy_from_slice(&self.buffer[1..1 + copy_len]);
+        Ok(copy_len)
+    }
+
+    /// Release an in-listed target.
+    pub fn in_release(&mut self, relevant_target: u8) -> Result<usize, Error<B::TransportError>> {
+        self.buffer[0] = PN532_COMMAND_INRELEASE;
+        self.buffer[1] = relevant_target;
+        self.send(2)?;
+        self.read()
+    }    
+}