144 lines
5.3 KiB
Python
144 lines
5.3 KiB
Python
# Adafruit PN532 NFC/RFID control library.
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# Author: Tony DiCola
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#
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# The MIT License (MIT)
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#
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# Copyright (c) 2015-2018 Adafruit Industries
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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"""
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``adafruit_pn532.i2c``
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====================================================
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This module will let you communicate with a PN532 RFID/NFC shield or breakout
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using I2C.
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* Author(s): Original Raspberry Pi code by Tony DiCola, CircuitPython by ladyada,
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refactor by Carter Nelson
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"""
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__version__ = "0.0.0-auto.0"
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__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_PN532.git"
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import time
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from machine import I2C, Pin
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from digitalio import Direction
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from micropython import const
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from adafruit_pn532 import PN532, BusyError, _reset
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# pylint: disable=bad-whitespace
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_I2C_ADDRESS = const(0x24)
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_NOT_BUSY = const(0x01)
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class PN532_I2C(PN532):
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"""Driver for the PN532 connected over I2C."""
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def __init__(self, i2c, *, irq=None, reset=None, req=None, debug=False):
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"""Create an instance of the PN532 class using I2C. Note that PN532
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uses clock stretching. Optional IRQ pin (not used),
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reset pin and debugging output.
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"""
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self.debug = debug
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self._irq = irq
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self._req = req
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if reset:
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# Changed this logic so it is not circuit python dependent (No use of direction)
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# Do the reset at the I2c level
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if self.debug:
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print("reset")
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reset_pin = Pin(reset, Pin.OUT)
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reset_pin.value(1)
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time.sleep(0.1)
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reset_pin.value(0)
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time.sleep(0.5)
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reset_pin.value(1)
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time.sleep(0.1)
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# _reset(reset)
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# self._i2c = I2C.SoftI2C(i2c, _I2C_ADDRESS)
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self._i2c = i2c
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# call super.__init__ without reset pin (To get around circuitpython pin specifics)
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super().__init__(debug=debug)
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def _wakeup(self): # pylint: disable=no-self-use
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"""Send any special commands/data to wake up PN532"""
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if self._req:
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self._req.direction = Direction.OUTPUT
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self._req.value = True
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time.sleep(0.1)
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self._req.value = False
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time.sleep(0.1)
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self._req.value = True
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time.sleep(0.5)
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def _wait_ready(self, timeout=1):
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"""Poll PN532 if status byte is ready, up to `timeout` seconds"""
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# Updated to use time_ns vs time.monotonic of circuitpython
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status = bytearray(1)
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timestamp = time.time_ns()/1000000000
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if self.debug:
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print("wait ready timestamp:", timestamp)
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while ((time.time_ns()/1000000000) - timestamp) < timeout:
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try:
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# with self._i2c:
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self._i2c.readfrom_into(_I2C_ADDRESS, status)
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except OSError:
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self._wakeup()
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continue
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if status == b'\x01':
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return True # No longer busy
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else:
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time.sleep(0.05) # lets ask again soon!
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# Timed out!
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if self.debug:
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print("wait_ready time.time_ns():", time.time_ns()/1000000000)
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return False
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def _read_data(self, count):
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"""Read a specified count of bytes from the PN532."""
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if self.debug:
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print("_read_data")
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# Build a read request frame.
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frame = bytearray(count+1)
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status_byte = bytearray(1)
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# Updated to use readfrom_into (Circutpython readfrom not supported)
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self._i2c.readfrom_into(_I2C_ADDRESS, status_byte)
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if self.debug:
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print("_read_data status_byte: ", status_byte)
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if status_byte[0] != _NOT_BUSY: # not ready
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if self.debug:
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print("_read_data busy_error ")
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raise BusyError
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if self.debug:
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print("_read_data readfrom_into")
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# Updated to use readfrom_into (Circutpython readfrom not supported)
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self._i2c.readfrom_into(_I2C_ADDRESS, frame)
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if self.debug:
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print("_read_data frame: ", frame)
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return frame[1:] # don't return the status byte
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def _write_data(self, framebytes):
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"""Write a specified count of bytes to the PN532"""
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# Updated to using writeto - circuitpython write not supported
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if self.debug:
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print('_write data: ', [hex(i) for i in framebytes])
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self._i2c.writeto(_I2C_ADDRESS, framebytes)
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