Library used: https://github.com/elechouse/PN532
Note: Library that comes with the taobao shop is extremely outdated ( for arduino 1.1 )
This particular instance using I2C
- Reader cannot have metal plate that's close to it ( or the metal plate will absorb all the energy that the reader emit )
- Removing card takes time for the Library to react ( will need to find an interrupt driven way if needs not to block the program )
- So best practice now if the main controller task is time-critical is to use another controller as slave that dedicated to reading nfc tag.
Modified from the library's i2c sample
#include <Wire.h> #include "PN532_I2C.h" #include "PN532.h" PN532_I2C m1kreader(Wire); PN532 nfc(m1kreader); void setup() { // Debug msg Serial.begin(115200); // Serial1.begin(115200); // send to touchboard // Start the TWI nfc.begin(); // Debug purpose (Block program for output) while (!Serial); 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); nfc.SAMConfig(); Serial.println("Waiting for an ISO14443A Card ..."); } void loop() { 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) success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength); 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 // data = { 'a', 'd', 'a', 'f', 'r', 'u', 'i', 't', '.', 'c', 'o', 'm', 0, 0, 0, 0}; // 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) for ( int i = 6; i <= 10; i++ ) { Serial.print("Reading page "); Serial.println( i ); uint8_t data[32]; success = nfc.mifareultralight_ReadPage (i, data); if (success) { // Data seems to have been read ... spit it out nfc.PrintHexChar(data, 32); Serial.println(""); // Wait a bit before reading the card again delay(5); } else { Serial.println("Ooops ... unable to read the requested page!?"); } } } } }