69 lines
2.1 KiB
Python
69 lines
2.1 KiB
Python
# SPDX-FileCopyrightText: 2015-2018 Tony DiCola for Adafruit Industries
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#
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# SPDX-License-Identifier: MIT
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"""
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``adafruit_pn532.uart``
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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 UART.
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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 adafruit_pn532.adafruit_pn532 import PN532, BusyError
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class PN532_UART(PN532):
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"""Driver for the PN532 connected over Serial UART"""
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def __init__(self, uart, *, reset=None, debug=False):
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"""Create an instance of the PN532 class using Serial connection.
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Optional reset pin and debugging output.
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"""
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self.debug = debug
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self._uart = uart
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super().__init__(debug=debug, reset=reset)
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def _wakeup(self):
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"""Send any special commands/data to wake up PN532"""
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if self._reset_pin:
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self._reset_pin.value = True
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time.sleep(0.01)
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self.low_power = False
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self._uart.write(
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b"\x55\x55\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
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) # wake up!
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self.SAM_configuration()
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def _wait_ready(self, timeout=1):
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"""Wait `timeout` seconds"""
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timestamp = time.monotonic()
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while (time.monotonic() - timestamp) < timeout:
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if self._uart.in_waiting > 0:
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return True # No Longer Busy
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time.sleep(0.01) # lets ask again soon!
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# Timed out!
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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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frame = self._uart.read(count)
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if not frame:
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raise BusyError("No data read from PN532")
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if self.debug:
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print("Reading: ", [hex(i) for i in frame])
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return frame
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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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self._uart.reset_input_buffer()
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self._uart.write(framebytes)
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