Added i2c support

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2022 Luiz Brandao
+Copyright (c) 2022 Luiz Brandao, Olaf van der Kruk
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -2,14 +2,43 @@
 MicroPython driver for PN532 NFC/RFID breakout boards. Based on the [CircuitPython driver by Adafruit](https://github.com/adafruit/Adafruit_CircuitPython_PN532).
 
 ### Compatibility
-This driver has only been tested with the ESP32 using the [Grove NFC breakout board](https://wiki.seeedstudio.com/Grove_NFC/) in the default UART mode. 
+This driver has only been tested with the ESP32 and RP2040 using the [Grove NFC breakout board](https://wiki.seeedstudio.com/Grove_NFC/) and the cheap Aliexpress modules in the default UART mode and I2C mode. 
 
 Please let me know if you get this module successfully working with other hardware.
 
+### Usage
+You can install the package using `mpremote` with the following command:
+```bash
+mpremote mip install "github:olijf/micropython_pn532/pn532"
+```
+
+
+```python
+from machine import Pin, I2C
+
+i2c = I2C(0, scl=Pin(5), sda=Pin(4))
+
+from i2c import PN532_I2C
+pn532 = PN532_I2C(i2c, debug=True)
+
+uid = pn532.read_passive_target(timeout=500)
+
+if uid is None:
+  print("No card detected")
+else:
+  print("Found card with UID:", [hex(i) for i in uid])
+```
+
 ### Differences in the API from the CircuitPython version
 
 - The timeout is expressed in milliseconds instead of seconds.
 - The module name is different.
-- Only UART is available
-- _I2C and SPI are not available._ 
+- Only UART and I2C is available
+- _SPI is not available._ 
+
+### TODO
+- [ ] Implement SPI
+- [ ] Rewrite the modules with asyncio support so we can use the library non blocking
+- [ ] Determine if thread blocking is really an issue when used
+- [ ] Add support for the other modes of the PN532, card emulation specifically
 

pn532/i2c.py

@@ -0,0 +1,68 @@
+"""
+``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, MicroPython by Olaf van der Kruk
+
+"""
+import time
+from pn532 import PN532, BusyError
+
+
+class PN532_I2C(PN532):
+    """Driver for the PN532 connected over I2C"""
+
+    def __init__(self, i2c, *, reset=None, debug=False, address=0x24):
+      """Create an instance of the PN532 class using I2C.
+      Optional reset pin and debugging output.
+      """
+      self.debug = debug
+      self._i2c = i2c
+      self._i2c_addr = address
+      super().__init__(debug=debug, reset=reset)
+
+    def _wakeup(self):
+      """Send any special commands/data to wake up PN532"""
+      if self.debug:
+        print("Waking up")
+      if self._reset_pin:
+          self._reset_pin.value = True
+          time.sleep(0.01)
+      self.low_power = False
+      #self._i2c.writeto(self._i2c_addr,
+      #    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=1000):
+      """Wait `timeout` milliseconds"""
+      status = bytearray(1)
+      start = time.ticks_ms()
+      while time.ticks_diff(time.ticks_ms(), start) < timeout:
+        try:
+          self._i2c.readfrom_into(self._i2c_addr, 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."""
+      frame = bytearray(count + 1)
+      self._i2c.readfrom_into(self._i2c_addr, frame)
+      if not frame:
+          raise BusyError("No data read from PN532")
+      if self.debug:
+          print("Reading: ", [hex(i) for i in frame])
+      return frame[1:]
+
+    def _write_data(self, framebytes):
+      """Write a specified count of bytes to the PN532"""
+      self._i2c.writeto(self._i2c_addr, framebytes)

pn532/package.json

@@ -0,0 +1,8 @@
+{
+    "urls": [
+      ["pn532.py", "github:olijf/micropython_pn532/pn532/pn532.py"],
+      ["uart.py", "github:olijf/micropython_pn532/pn532/uart.py"],
+      ["i2c.py", "github:olijf/micropython_pn532/pn532/i2c.py"]
+    ],
+    "version": "0.1"
+  }