144 lines
5.1 KiB
Python
144 lines
5.1 KiB
Python
# 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
|
|
from adafruit_bus_device import i2c_device
|
|
from digitalio import Direction
|
|
from micropython import const
|
|
from adafruit_pn532.adafruit_pn532 import PN532, BusyError
|
|
|
|
try:
|
|
from typing import Optional
|
|
from digitalio import DigitalInOut # pylint: disable=ungrouped-imports
|
|
from busio import I2C
|
|
except ImportError:
|
|
pass
|
|
|
|
_I2C_ADDRESS = const(0x24)
|
|
|
|
|
|
class PN532_I2C(PN532):
|
|
"""Driver for the PN532 connected over I2C."""
|
|
|
|
def __init__(
|
|
self,
|
|
i2c: I2C,
|
|
address: int = _I2C_ADDRESS,
|
|
*,
|
|
irq: Optional[DigitalInOut] = None,
|
|
reset: Optional[DigitalInOut] = None,
|
|
req: Optional[DigitalInOut] = None,
|
|
debug: bool = False
|
|
) -> None:
|
|
"""Create an instance of the PN532 class using I2C. Note that PN532
|
|
uses clock stretching. Optional IRQ pin (not used),
|
|
resetp pin and debugging output.
|
|
|
|
:param ~busio.I2C i2c: The I2C bus the PN532 is connected to.
|
|
:param int address: The I2C device address. Defaults to :const:`0x24`
|
|
:param digitalio.DigitalInOut irq: board pin the PN532 IRQ is connected to
|
|
:param digitalio.DigitalInOut reset: board pin the PN532 RSTOUT_N is connected to
|
|
:param digitalio.DigitalInOut req: board pin the PN532 P32 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
|
|
|
|
.. code-block:: python
|
|
|
|
import board
|
|
import busio
|
|
from digitalio import DigitalInOut
|
|
from adafruit_pn532.i2c import PN532_I2C
|
|
|
|
Once this is done you can define your `board.I2C` object and define your object
|
|
|
|
.. code-block:: python
|
|
|
|
i2c = busio.I2C(board.SCL, board.SDA)
|
|
reset_pin = DigitalInOut(board.D6)
|
|
# On Raspberry Pi, you must also connect a pin to P32 "H_Request" for hardware
|
|
# wakeup! this means we don't need to do the I2C clock-stretch thing
|
|
req_pin = DigitalInOut(board.D12)
|
|
pn532 = PN532_I2C(i2c, debug=False, reset=reset_pin, req=req_pin)
|
|
# Configure PN532 to communicate with MiFare cards
|
|
pn532.SAM_configuration()
|
|
|
|
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._req = req
|
|
self._i2c = i2c_device.I2CDevice(i2c, address)
|
|
super().__init__(debug=debug, irq=irq, 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)
|
|
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: float = 1) -> bool:
|
|
"""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) # let's ask again soon!
|
|
# Timed out!
|
|
return False
|
|
|
|
def _read_data(self, count: int) -> bytearray:
|
|
"""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: bytes) -> None:
|
|
"""Write a specified count of bytes to the PN532"""
|
|
with self._i2c as i2c:
|
|
i2c.write(framebytes)
|