/**

* ----------------------------------------------------------------------------

* This is a MFRC522 library example; see https://github.com/miguelbalboa/rfid

* for further details and other examples.

*

* NOTE: The library file MFRC522.h has a lot of useful info. Please read it.

*

* Released into the public domain.

* ----------------------------------------------------------------------------

* This sample shows how to read and write data blocks on a MIFARE Classic PICC

* (= card/tag).

*

* BEWARE: Data will be written to the PICC, in sector #1 (blocks #4 to #7).

*

*

* Typical pin layout used:

* -----------------------------------------------------------------------------------------

* MFRC522 Arduino Arduino Arduino Arduino Arduino

* Reader/PCD Uno Mega Nano v3 Leonardo/Micro Pro Micro

* Signal Pin Pin Pin Pin Pin Pin

* -----------------------------------------------------------------------------------------

* RST/Reset RST 9 5 D9 RESET/ICSP-5 RST

* SPI SS SDA(SS) 10 53 D10 10 10

* SPI MOSI MOSI 11 / ICSP-4 51 D11 ICSP-4 16

* SPI MISO MISO 12 / ICSP-1 50 D12 ICSP-1 14

* SPI SCK SCK 13 / ICSP-3 52 D13 ICSP-3 15

*

*/

#include <SPI.h>

#include <MFRC522.h>

#define RST_PIN 9 // Configurable, see typical pin layout above

#define SS_PIN 10 // Configurable, see typical pin layout above

MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.

MFRC522::MIFARE_Key key;

/**

* Initialize.

*/

void setup() {

Serial.begin(9600); // Initialize serial communications with the PC

while (!Serial); // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)

SPI.begin(); // Init SPI bus

mfrc522.PCD_Init(); // Init MFRC522 card

// Prepare the key (used both as key A and as key B)

// using FFFFFFFFFFFFh which is the default at chip delivery from the factory

for (byte i = 0; i < 6; i++) {

key.keyByte[i] = 0xFF;

}

Serial.println(F("Scan a MIFARE Classic PICC to demonstrate read and write."));

Serial.print(F("Using key (for A and B):"));

dump_byte_array(key.keyByte, MFRC522::MF_KEY_SIZE);

Serial.println();

Serial.println(F("BEWARE: Data will be written to the PICC, in sector #1"));

}

/**

* Main loop.

*/

void loop() {

// Look for new cards

if ( ! mfrc522.PICC_IsNewCardPresent())

return;

// Select one of the cards

if ( ! mfrc522.PICC_ReadCardSerial())

return;

// Show some details of the PICC (that is: the tag/card)

Serial.print(F("Card UID:"));

dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);

Serial.println();

Serial.print(F("PICC type: "));

MFRC522::PICC_Type piccType = mfrc522.PICC_GetType(mfrc522.uid.sak);

Serial.println(mfrc522.PICC_GetTypeName(piccType));

// Check for compatibility

if ( piccType != MFRC522::PICC_TYPE_MIFARE_MINI

&& piccType != MFRC522::PICC_TYPE_MIFARE_1K

&& piccType != MFRC522::PICC_TYPE_MIFARE_4K) {

Serial.println(F("This sample only works with MIFARE Classic cards."));

return;

}

// In this sample we use the second sector,

// that is: sector #1, covering block #4 up to and including block #7

byte sector = 1;

byte blockAddr = 4;

byte dataBlock[] = {

0x01, 0x02, 0x03, 0x04, // 1, 2, 3, 4,

0x05, 0x06, 0x07, 0x08, // 5, 6, 7, 8,

0x08, 0x09, 0xff, 0x0b, // 9, 10, 255, 12,

0x0c, 0x0d, 0x0e, 0x0f // 13, 14, 15, 16

};

byte trailerBlock = 7;

MFRC522::StatusCode status;

byte buffer[18];

byte size = sizeof(buffer);

// Authenticate using key A

Serial.println(F("Authenticating using key A..."));

status = (MFRC522::StatusCode) mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_A, trailerBlock, &key, &(mfrc522.uid));

if (status != MFRC522::STATUS_OK) {

Serial.print(F("PCD_Authenticate() failed: "));

Serial.println(mfrc522.GetStatusCodeName(status));

return;

}

// Show the whole sector as it currently is

Serial.println(F("Current data in sector:"));

mfrc522.PICC_DumpMifareClassicSectorToSerial(&(mfrc522.uid), &key, sector);

Serial.println();

// Read data from the block

Serial.print(F("Reading data from block ")); Serial.print(blockAddr);

Serial.println(F(" ..."));

status = (MFRC522::StatusCode) mfrc522.MIFARE_Read(blockAddr, buffer, &size);

if (status != MFRC522::STATUS_OK) {

Serial.print(F("MIFARE_Read() failed: "));

Serial.println(mfrc522.GetStatusCodeName(status));

}

Serial.print(F("Data in block ")); Serial.print(blockAddr); Serial.println(F(":"));

dump_byte_array(buffer, 16); Serial.println();

Serial.println();

// Authenticate using key B

Serial.println(F("Authenticating again using key B..."));

status = (MFRC522::StatusCode) mfrc522.PCD_Authenticate(MFRC522::PICC_CMD_MF_AUTH_KEY_B, trailerBlock, &key, &(mfrc522.uid));

if (status != MFRC522::STATUS_OK) {

Serial.print(F("PCD_Authenticate() failed: "));

Serial.println(mfrc522.GetStatusCodeName(status));

return;

}

// Write data to the block

Serial.print(F("Writing data into block ")); Serial.print(blockAddr);

Serial.println(F(" ..."));

dump_byte_array(dataBlock, 16); Serial.println();

status = (MFRC522::StatusCode) mfrc522.MIFARE_Write(blockAddr, dataBlock, 16);

if (status != MFRC522::STATUS_OK) {

Serial.print(F("MIFARE_Write() failed: "));

Serial.println(mfrc522.GetStatusCodeName(status));

}

Serial.println();

// Read data from the block (again, should now be what we have written)

Serial.print(F("Reading data from block ")); Serial.print(blockAddr);

Serial.println(F(" ..."));

status = (MFRC522::StatusCode) mfrc522.MIFARE_Read(blockAddr, buffer, &size);

if (status != MFRC522::STATUS_OK) {

Serial.print(F("MIFARE_Read() failed: "));

Serial.println(mfrc522.GetStatusCodeName(status));

}

Serial.print(F("Data in block ")); Serial.print(blockAddr); Serial.println(F(":"));

dump_byte_array(buffer, 16); Serial.println();

// Check that data in block is what we have written

// by counting the number of bytes that are equal

Serial.println(F("Checking result..."));

byte count = 0;

for (byte i = 0; i < 16; i++) {

// Compare buffer (= what we've read) with dataBlock (= what we've written)

if (buffer[i] == dataBlock[i])

count++;

}

Serial.print(F("Number of bytes that match = ")); Serial.println(count);

if (count == 16) {

Serial.println(F("Success :-)"));

} else {

Serial.println(F("Failure, no match :-("));

Serial.println(F(" perhaps the write didn't work properly..."));

}

Serial.println();

// Dump the sector data

Serial.println(F("Current data in sector:"));

mfrc522.PICC_DumpMifareClassicSectorToSerial(&(mfrc522.uid), &key, sector);

Serial.println();

// Halt PICC

mfrc522.PICC_HaltA();

// Stop encryption on PCD

mfrc522.PCD_StopCrypto1();

}

/**

* Helper routine to dump a byte array as hex values to Serial.

*/

void dump_byte_array(byte *buffer, byte bufferSize) {

for (byte i = 0; i < bufferSize; i++) {

Serial.print(buffer[i] < 0x10 ? " 0" : " ");

Serial.print(buffer[i], HEX);

}

}