initial commit

examples/ntag21x_protect/ntag21x_protect.ino

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+// NTAG21x supports 4 bytes password to protect pages started from AUTH0
+// AUTH0 defines the page address from which the password verification is required.
+// Valid address range for byte AUTH0 is from 00h to FFh.
+// If AUTH0 is set to a page address which is higher than the last page from the user configuration,
+// the password protection is effectively disabled
+
+#if 0       // Using PN532's SPI (Seeed NFC shield)
+#include <SPI.h>
+#include <PN532_SPI.h>
+#include <PN532.h>
+#include <NfcAdapter.h>
+
+PN532_SPI intf(SPI, 10);
+PN532 nfc = PN532(intf);
+#else        // Using PN532's I2C
+#include <Wire.h>
+#include <PN532_I2C.h>
+#include <PN532.h>
+#include <NfcAdapter.h>
+
+PN532_I2C intf(Wire);
+PN532 nfc = PN532(intf);
+#endif
+
+// Using PN532's UART (Grove NFC)
+
+// #include <PN532_I2C.h>
+// #include <PN532.h>
+// #include <NfcAdapter.h>
+// PN532_HSU intf(Serial1);
+// PN532 nfc = PN532(intf);
+
+
+uint8_t password[4] =  {0x12, 0x34, 0x56, 0x78};
+uint8_t buf[4];
+uint8_t uid[7]; 
+uint8_t uidLength;
+
+void setup(void) {
+    Serial.begin(9600);
+    Serial.println("NTAG21x R/W");
+
+    nfc.begin();
+    nfc.SAMConfig();
+}
+
+void loop(void) {
+    Serial.println("wait for a tag");
+    // wait until a tag is present
+    while (!nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength)) {
+
+    }
+
+    // if NTAG21x enables r/w protection, uncomment the following line 
+    // nfc.ntag21x_auth(password);
+
+    nfc.mifareultralight_ReadPage(3, buf);
+    int capacity = buf[2] * 8;
+    Serial.print(F("Tag capacity "));
+    Serial.print(capacity);
+    Serial.println(F(" bytes"));
+
+    uint8_t cfg_page_base = 0x29;   // NTAG213
+    if (capacity == 0x3E) {
+        cfg_page_base = 0x83;       // NTAG215
+    } else if (capacity == 0x6D) {
+        cfg_page_base = 0xE3;       // NTAG216
+    }
+
+    // PWD page, set new password
+    nfc.mifareultralight_WritePage(cfg_page_base + 2, password);
+    
+    // disable r/w
+    // | PROT | CFG_LCK | RFUI | NFC_CNT_EN | NFC_CNT_PWD_PROT | AUTHLIM (2:0) |
+    buf[0] = (1 << 7) | 0x0;
+    nfc.mifareultralight_WritePage(cfg_page_base + 1, buf);
+
+    // protect pages started from AUTH0
+    uint8_t auth0 = 0x10;
+    buf[0] = 0;
+    buf[1] = 0;
+    buf[2] = 0;
+    buf[3] = auth0;
+    nfc.mifareultralight_WritePage(cfg_page_base, buf);
+
+
+    // wait until the tag is removed
+    while (nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength)) {
+
+    }
+}