# SPDX-FileCopyrightText: 2015-2018 Tony DiCola for Adafruit Industries # # SPDX-License-Identifier: MIT """ ``adafruit_pn532.uart`` ==================================================== This module will let you communicate with a PN532 RFID/NFC shield or breakout using UART. * Author(s): Original Raspberry Pi code by Tony DiCola, CircuitPython by ladyada, refactor by Carter Nelson """ __version__ = "0.0.0+auto.0" __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_PN532.git" from machine import UART, Pin try: from typing import Optional, Union except ImportError: pass import time from pn532.pn532 import PN532, BusyError class PN532_UART(PN532): """Driver for the PN532 connected over Serial UART""" def __init__( self, uart: UART, *, reset: Optional[int] = None, debug: bool = False ) -> None: """Create an instance of the PN532 class using Serial connection. Optional reset pin and debugging output. :param ~busio.UART uart: The uart object the PN532 is connected to. :param digitalio.DigitalInOut reset: board pin the PN532 RSTOUT_N is connected to :param bool debug: if True print additional debug statements. Defaults to False **Quickstart: Importing and using the device** Here is an example of using the :class:`PN532_I2C` class. First you will need to import the libraries to use the sensor Once this is done you can define your `machine.UART` object and define your PN532 object .. code-block:: python uart = machine.UART(0) uart.init(baudrate=115200, bits=8, parity=None, stop=1, tx=0, rx=1) pn532 = PN532_UART(uart, debug=False) Now you have access to the attributes and functions of the PN532 RFID/NFC shield or breakout .. code-block:: python uid = pn532.read_passive_target(timeout=0.5) """ self.debug = debug self._uart = uart super().__init__(debug=debug, reset=reset) def _wakeup(self) -> None: """Send any special commands/data to wake up PN532""" if self._reset_pin: self._reset_pin.value = True time.sleep(0.01) self.low_power = False self._uart.write( b"\x55\x55\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" ) # wake up! self.SAM_configuration() def _wait_ready(self, timeout: float = 1) -> bool: """Wait `timeout` seconds""" timestamp = time.monotonic() while (time.monotonic() - timestamp) < timeout: if self._uart.in_waiting > 0: return True # No Longer Busy time.sleep(0.01) # lets ask again soon! # Timed out! return False def _read_data(self, count: int) -> bytes: """Read a specified count of bytes from the PN532.""" frame = self._uart.read(count) if not frame: raise BusyError("No data read from PN532") if self.debug: print("Reading: ", [hex(i) for i in frame]) return frame def _write_data(self, framebytes: Union[bytes, bytearray]) -> None: """Write a specified count of bytes to the PN532""" self._uart.reset_input_buffer() self._uart.write(framebytes)