Merge pull request #66 from symm/mifare-value-block

Add support for Mifare classic value block operations
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foamyguy 2023-10-22 21:03:48 -05:00 committed by GitHub
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@ -27,6 +27,7 @@ Implementation Notes
"""
import time
import struct
from digitalio import Direction
from micropython import const
@ -501,6 +502,101 @@ class PN532:
)
return response[0] == 0x0
def mifare_classic_sub_value_block(self, block_number: int, amount: int) -> bool:
"""Decrease the balance of a value block. Block number should be the block
to change and amount should be an integer up to a maximum of 2147483647.
If the value block is successfully updated then True is returned,
otherwise False is returned.
"""
params = [0x01, MIFARE_CMD_DECREMENT, block_number & 0xFF]
params.extend(list(amount.to_bytes(4, "little")))
response = self.call_function(
_COMMAND_INDATAEXCHANGE, params=params, response_length=1
)
if response[0] != 0x00:
return False
response = self.call_function(
_COMMAND_INDATAEXCHANGE,
params=[0x01, MIFARE_CMD_TRANSFER, block_number & 0xFF],
response_length=1,
)
return response[0] == 0x00
def mifare_classic_add_value_block(self, block_number: int, amount: int) -> bool:
"""Increase the balance of a value block. Block number should be the block
to change and amount should be an integer up to a maximum of 2147483647.
If the value block is successfully updated then True is returned,
otherwise False is returned.
"""
params = [0x01, MIFARE_CMD_INCREMENT, block_number & 0xFF]
params.extend(list(amount.to_bytes(4, "little")))
response = self.call_function(
_COMMAND_INDATAEXCHANGE, params=params, response_length=1
)
if response[0] != 0x00:
return False
response = self.call_function(
_COMMAND_INDATAEXCHANGE,
params=[0x01, MIFARE_CMD_TRANSFER, block_number & 0xFF],
response_length=1,
)
return response[0] == 0x00
def mifare_classic_get_value_block(self, block_number: int) -> int:
"""Read the contents of a value block and return a integer representing the
current balance. Block number should be the block to read.
"""
block = self.mifare_classic_read_block(block_number=block_number)
if block is None:
return None
value = block[0:4]
value_inverted = block[4:8]
value_backup = block[8:12]
if value != value_backup:
raise RuntimeError(
"Value block bytes 0-3 do not match 8-11: "
+ "".join("%02x" % b for b in block)
)
if value_inverted != bytearray(map((lambda x: x ^ 0xFF), value)):
raise RuntimeError(
"Inverted value block bytes 4-7 not valid: "
+ "".join("%02x" % b for b in block)
)
return struct.unpack("<i", value)[0]
def mifare_classic_fmt_value_block(
self, block_number: int, initial_value: int, address_block: int = 0
) -> bool:
"""Formats a block on the card so it is suitable for use as a value block.
Block number should be the block to use. Initial value should be an integer
up to a maximum of 2147483647. Address block is optional and can be used
as part of backup management.
"""
data = bytearray()
initial_value = initial_value.to_bytes(4, "little")
# Value
data.extend(initial_value)
# Inverted value
data.extend(bytearray(map((lambda x: x ^ 0xFF), initial_value)))
# Duplicate of value
data.extend(initial_value)
# Address
address_block = address_block.to_bytes(1, "little")[0]
data.extend(
[address_block, address_block ^ 0xFF, address_block, address_block ^ 0xFF]
)
return self.mifare_classic_write_block(block_number, data)
def ntag2xx_write_block(self, block_number: int, data: ReadableBuffer) -> bool:
"""Write a block of data to the card. Block number should be the block
to write and data should be a byte array of length 4 with the data to

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@ -0,0 +1,101 @@
# SPDX-FileCopyrightText: <text> 2015 Tony DiCola, Roberto Laricchia,
# and Francesco Crisafulli, for Adafruit Industries </text>
# SPDX-License-Identifier: MIT
# Example of detecting and reading a value block from a MiFare classic NFC card.
"""
This example shows connecting to the PN532 and writing & reading a mifare classic
type RFID tag
"""
import board
import busio
# Additional import needed for I2C/SPI
# from digitalio import DigitalInOut
#
# NOTE: pick the import that matches the interface being used
#
from adafruit_pn532.adafruit_pn532 import MIFARE_CMD_AUTH_B
from adafruit_pn532.i2c import PN532_I2C
# from adafruit_pn532.spi import PN532_SPI
# from adafruit_pn532.uart import PN532_UART
# I2C connection:
i2c = busio.I2C(board.SCL, board.SDA)
# Non-hardware reset/request with I2C
pn532 = PN532_I2C(i2c, debug=False)
# With I2C, we recommend connecting RSTPD_N (reset) to a digital pin for manual
# harware reset
# 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)
# SPI connection:
# spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
# cs_pin = DigitalInOut(board.D5)
# pn532 = PN532_SPI(spi, cs_pin, debug=False)
# UART connection
# uart = busio.UART(board.TX, board.RX, baudrate=115200, timeout=0.1)
# pn532 = PN532_UART(uart, debug=False)
ic, ver, rev, support = pn532.firmware_version
print("Found PN532 with firmware version: {0}.{1}".format(ver, rev))
# Configure PN532 to communicate with MiFare cards
pn532.SAM_configuration()
print("Waiting for RFID/NFC card to write to!")
key_a = b"\xFF\xFF\xFF\xFF\xFF\xFF"
key_b = b"\xFF\xFF\xFF\xFF\xFF\xFF"
while True:
# Check if a card is available to read
uid = pn532.read_passive_target(timeout=0.5)
print(".", end="")
# Try again if no card is available.
if uid is not None:
break
print("")
print("Found card with UID:", [hex(i) for i in uid])
print("Authenticating block 4 ...")
authenticated = pn532.mifare_classic_authenticate_block(
uid, 4, MIFARE_CMD_AUTH_B, key_b
)
if not authenticated:
print("Authentication failed!")
# Format block and set initial balance of 100
response = pn532.mifare_classic_fmt_value_block(4, 100)
print(
response,
"Formatted block 4, balance is:",
pn532.mifare_classic_get_value_block(4),
)
response = pn532.mifare_classic_sub_value_block(4, 50)
print(
response,
"Decrease by 50, new balance:",
pn532.mifare_classic_get_value_block(4),
)
response = pn532.mifare_classic_add_value_block(4, 1337)
print(
response,
"Increase by 1337, new balance:",
pn532.mifare_classic_get_value_block(4),
)