#include <Wire.h>
#include <SPI.h>
#include <Adafruit_PN532.h>
// If using the breakout with SPI, define the pins for SPI communication.
#define PN532_SCK (2)
#define PN532_MOSI (3)
#define PN532_SS (4)
#define PN532_MISO (5)
// If using the breakout or shield with I2C, define just the pins connected
// to the IRQ and reset lines. Use the values below (2, 3) for the shield!
#define PN532_IRQ (2)
#define PN532_RESET (3) // Not connected by default on the NFC Shield
// Uncomment just _one_ line below depending on how your breakout or shield
// is connected to the Arduino:
// Use this line for a breakout with a software SPI connection (recommended):
//Adafruit_PN532 nfc(PN532_SCK, PN532_MISO, PN532_MOSI, PN532_SS);
// Use this line for a breakout with a hardware SPI connection. Note that
// the PN532 SCK, MOSI, and MISO pins need to be connected to the Arduino's
// hardware SPI SCK, MOSI, and MISO pins. On an Arduino Uno these are
// SCK = 13, MOSI = 11, MISO = 12. The SS line can be any digital IO pin.
//Adafruit_PN532 nfc(PN532_SS);
// Or use this line for a breakout or shield with an I2C connection:
Adafruit_PN532 nfc(PN532_IRQ, PN532_RESET);
//Variables
const int buttonPin = 3;
int buttonState = 0;
void setup(void) {
Serial.begin(115200);
pinMode(buttonPin, INPUT);
while (!Serial) delay(10); // for Leonardo/Micro/Zero
Serial.println("Hello!");
nfc.begin();
uint32_t versiondata = nfc.getFirmwareVersion();
if (! versiondata) {
Serial.print("Didn't find PN53x board");
while (1); // halt
}
// Got ok data, print it out!
Serial.print("Found chip PN5"); Serial.println((versiondata>>24) & 0xFF, HEX);
Serial.print("Firmware ver. "); Serial.print((versiondata>>16) & 0xFF, DEC);
Serial.print('.'); Serial.println((versiondata>>8) & 0xFF, DEC);
// configure board to read RFID tags
nfc.SAMConfig();
attachInterrupt(digitalPinToInterrupt(buttonPin), buttonDown, CHANGE);
Serial.println("Waiting for an ISO14443A Card ...");
}
void loop(void) {
buttonState = digitalRead(buttonPin);
Serial.println(buttonState);
uint8_t success;
uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 }; // Buffer to store the returned UID
uint8_t uidLength; // Length of the UID (4 or 7 bytes depending on ISO14443A card type)
// Wait for an ISO14443A type cards (Mifare, etc.). When one is found
// 'uid' will be populated with the UID, and uidLength will indicate
// if the uid is 4 bytes (Mifare Classic) or 7 bytes (Mifare Ultralight)
while (digitalRead(buttonPin) == HIGH){
success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength, 6000);
if (success) {
// Display some basic information about the card
Serial.println("Found an ISO14443A card");
Serial.print(" UID Length: ");Serial.print(uidLength, DEC);Serial.println(" bytes");
Serial.print(" UID Value: ");
nfc.PrintHex(uid, uidLength);
Serial.println("");
if (uidLength == 4)
{
// We probably have a Mifare Classic card ...
Serial.println("Seems to be a Mifare Classic card (4 byte UID)");
// Now we need to try to authenticate it for read/write access
// Try with the factory default KeyA: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF
Serial.println("Trying to authenticate block 4 with default KEYA value");
uint8_t keya[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
// Start with block 4 (the first block of sector 1) since sector 0
// contains the manufacturer data and it's probably better just
// to leave it alone unless you know what you're doing
success = nfc.mifareclassic_AuthenticateBlock(uid, uidLength, 4, 0, keya);
if (success)
{
Serial.println("Sector 1 (Blocks 4..7) has been authenticated");
uint8_t data[16];
// If you want to write something to block 4 to test with, uncomment
// the following line and this text should be read back in a minute
//memcpy(data, (const uint8_t[]){ 'a', 'd', 'a', 'f', 'r', 'u', 'i', 't', '.', 'c', 'o', 'm', 0, 0, 0, 0 }, sizeof data);
// success = nfc.mifareclassic_WriteDataBlock (4, data);
// Try to read the contents of block 4
success = nfc.mifareclassic_ReadDataBlock(4, data);
if (success)
{
// Data seems to have been read ... spit it out
Serial.println("Reading Block 4:");
nfc.PrintHexChar(data, 16);
Serial.println("");
// Wait a bit before reading the card again
delay(1000);
}
else
{
Serial.println("Ooops ... unable to read the requested block. Try another key?");
}
}
else
{
Serial.println("Ooops ... authentication failed: Try another key?");
}
}
if (uidLength == 7)
{
// We probably have a Mifare Ultralight card ...
Serial.println("Seems to be a Mifare Ultralight tag (7 byte UID)");
// Try to read the first general-purpose user page (#4)
Serial.println("Reading page 4");
uint8_t data[32];
success = nfc.mifareultralight_ReadPage (4, data);
if (success)
{
// Data seems to have been read ... spit it out
nfc.PrintHexChar(data, 4);
Serial.println("");
// Wait a bit before reading the card again
delay(1000);
}
else
{
Serial.println("Ooops ... unable to read the requested page!?");
}
}
}
}
while (digitalRead(buttonPin)== LOW){
Serial.println("Button Up");
delay(1000);
buttonState = digitalRead(buttonPin);
}
}
The aim of this code is to only read RFID tags when a push button is pressed. When I press the button, it reads the right state and when I release it, it also displays the right state. However, when I press it again, it remains in a locked state and doesn't change.
The button has a wire going from 5V, a wire going to pin 3 and a 10k ohm resistor going to ground.
A lot of this code is example code from the P532 library.