# SPDX-FileCopyrightText: 2015-2018 Tony DiCola for Adafruit Industries # # SPDX-License-Identifier: MIT """ ``adafruit_pn532.i2c`` ==================================================== This module will let you communicate with a PN532 RFID/NFC shield or breakout using I2C. * 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" import time import adafruit_bus_device.i2c_device as i2c_device from digitalio import Direction from micropython import const from adafruit_pn532.adafruit_pn532 import PN532, BusyError _I2C_ADDRESS = const(0x24) class PN532_I2C(PN532): """Driver for the PN532 connected over I2C.""" def __init__(self, i2c, *, irq=None, reset=None, req=None, debug=False): """Create an instance of the PN532 class using I2C. Note that PN532 uses clock stretching. Optional IRQ pin (not used), reset pin and debugging output. """ self.debug = debug self._req = req self._i2c = i2c_device.I2CDevice(i2c, _I2C_ADDRESS) super().__init__(debug=debug, irq=irq, reset=reset) def _wakeup(self): # pylint: disable=no-self-use """Send any special commands/data to wake up PN532""" if self._reset_pin: self._reset_pin.value = True time.sleep(0.01) if self._req: self._req.direction = Direction.OUTPUT self._req.value = False time.sleep(0.01) self._req.value = True time.sleep(0.01) self.low_power = False self.SAM_configuration() # Put the PN532 back in normal mode def _wait_ready(self, timeout=1): """Poll PN532 if status byte is ready, up to `timeout` seconds""" status = bytearray(1) timestamp = time.monotonic() while (time.monotonic() - timestamp) < timeout: try: with self._i2c: self._i2c.readinto(status) except OSError: continue if status == b"\x01": return True # No longer busy time.sleep(0.01) # lets ask again soon! # Timed out! return False def _read_data(self, count): """Read a specified count of bytes from the PN532.""" # Build a read request frame. frame = bytearray(count + 1) with self._i2c as i2c: i2c.readinto(frame, end=1) # read status byte! if frame[0] != 0x01: # not ready raise BusyError i2c.readinto(frame) # ok get the data, plus statusbyte if self.debug: print("Reading: ", [hex(i) for i in frame[1:]]) return frame[1:] # don't return the status byte def _write_data(self, framebytes): """Write a specified count of bytes to the PN532""" with self._i2c as i2c: i2c.write(framebytes)