erase(), format(), clean()

erase - erases tag by writing an empty NDEF record format - format tag as NDEF (Mifare Classic only) clean - reset a tag to factory state (or close to factory state) Mifare Classic format now adds an empty NDEF record
don · Aug 25, 2014 · c2da758 · c2da758
1 parent 56a4461
commit c2da758
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Showing 5 changed files with 84 additions and 21 deletions.
diff --git a/MifareClassic.cpp b/MifareClassic.cpp
@@ -186,9 +186,12 @@ bool MifareClassic::decodeTlv(byte *data, int &messageLength, int &messageStartI
     return true;
 }
 
+// Intialized NDEF tag contains one empty NDEF TLV 03 00 FE - AN1304 6.3.1
+// We are formatting in read/write mode with a NDEF TLV 03 03 and an empty NDEF record D0 00 00 FE - AN1304 6.3.2
 boolean MifareClassic::formatNDEF(byte * uid, unsigned int uidLength)
 {
     uint8_t keya[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+    uint8_t emptyNdefMesg[16] = {0x03, 0x03, 0xD0, 0x00, 0x00, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
     uint8_t sectorbuffer0[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
     uint8_t sectorbuffer4[16] = {0xD3, 0xF7, 0xD3, 0xF7, 0xD3, 0xF7, 0x7F, 0x07, 0x88, 0x40, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
 
@@ -207,10 +210,21 @@ boolean MifareClassic::formatNDEF(byte * uid, unsigned int uidLength)
     {
         for (int i=4; i<64; i+=4) {
             success = _nfcShield->mifareclassic_AuthenticateBlock (uid, uidLength, i, 0, keya);
+
             if (success) {
-                if (!(_nfcShield->mifareclassic_WriteDataBlock (i, sectorbuffer0)))
+                if (i == 4)  // special handling for block 4
+                {
+                    if (!(_nfcShield->mifareclassic_WriteDataBlock (i, emptyNdefMesg)))
+                    {
+                        Serial.print(F("Unable to write block "));Serial.println(i);
+                    }
+                }
+                else
                 {
-                    Serial.print(F("Unable to write block "));Serial.println(i);
+                    if (!(_nfcShield->mifareclassic_WriteDataBlock (i, sectorbuffer0)))
+                    {
+                        Serial.print(F("Unable to write block "));Serial.println(i);
+                    }
                 }
                 if (!(_nfcShield->mifareclassic_WriteDataBlock (i+1, sectorbuffer0)))
                 {

diff --git a/MifareUltralight.cpp b/MifareUltralight.cpp
@@ -170,25 +170,25 @@ boolean MifareUltralight::write(NdefMessage& m, byte * uid, unsigned int uidLeng
         return false;
     }
     readCapabilityContainer(); // meta info for tag
-    
+
     messageLength  = m.getEncodedSize();
     ndefStartIndex = messageLength < 0xFF ? 2 : 4;
     calculateBufferSize();
-    
+
     if(bufferSize>tagCapacity) {
 	    #ifdef MIFARE_ULTRALIGHT_DEBUG
     	Serial.print(F("Encoded Message length exceeded tag Capacity "));Serial.println(tagCapacity);
     	#endif
     	return false;
     }
-    
+
     uint8_t encoded[bufferSize];
     uint8_t *  src = encoded;
     unsigned int position = 0;
     uint8_t page = ULTRALIGHT_DATA_START_PAGE;
-        
+
     // Set message size. With ultralight should always be less than 0xFF but who knows?
-    
+
     encoded[0] = 0x3;
     if (messageLength < 0xFF)
     {
@@ -200,24 +200,24 @@ boolean MifareUltralight::write(NdefMessage& m, byte * uid, unsigned int uidLeng
         encoded[2] = ((messageLength >> 8) & 0xFF);
         encoded[3] = (messageLength & 0xFF);
     }
-    
+
     m.encode(encoded+ndefStartIndex);
     // this is always at least 1 byte copy because of terminator.
-    memset(encoded+ndefStartIndex+messageLength,0,bufferSize-ndefStartIndex-messageLength);    
+    memset(encoded+ndefStartIndex+messageLength,0,bufferSize-ndefStartIndex-messageLength);
     encoded[ndefStartIndex+messageLength] = 0xFE; // terminator
-    
+
     #ifdef MIFARE_ULTRALIGHT_DEBUG
     Serial.print(F("messageLength "));Serial.println(messageLength);
     Serial.print(F("Tag Capacity "));Serial.println(tagCapacity);
     nfc->PrintHex(encoded,bufferSize);
     #endif
-    
+
     while (position < bufferSize){ //bufferSize is always times pagesize so no "last chunk" check
         // write page
         if (!nfc->mifareultralight_WritePage(page, src))
             return false;
 		#ifdef MIFARE_ULTRALIGHT_DEBUG
-    	Serial.print(F("Written page "));Serial.print(page);Serial.print(F(" - "));
+        Serial.print(F("Wrote page "));Serial.print(page);Serial.print(F(" - "));
     	nfc->PrintHex(src,ULTRALIGHT_PAGE_SIZE);
     	#endif
         page++;
@@ -226,3 +226,26 @@ boolean MifareUltralight::write(NdefMessage& m, byte * uid, unsigned int uidLeng
     }
     return true;
 }
+
+// Mifare Ultralight can't be reset to factory state
+// zero out tag data like the NXP Tag Write Android application
+boolean MifareUltralight::clean()
+{
+    readCapabilityContainer(); // meta info for tag
+
+    uint8_t pages = (tagCapacity / ULTRALIGHT_PAGE_SIZE) + ULTRALIGHT_DATA_START_PAGE;
+
+    // factory tags have 0xFF, but OTP-CC blocks have already been set so we use 0x00
+    uint8_t data[4] = { 0x00, 0x00, 0x00, 0x00 };
+
+    for (int i = ULTRALIGHT_DATA_START_PAGE; i < pages; i++) {
+        #ifdef MIFARE_ULTRALIGHT_DEBUG
+        Serial.print(F("Wrote page "));Serial.print(i);Serial.print(F(" - "));
+        nfc->PrintHex(data, ULTRALIGHT_PAGE_SIZE);
+        #endif
+        if (!nfc->mifareultralight_WritePage(i, data)) {
+            return false;
+        }
+    }
+    return true;
+}
diff --git a/MifareUltralight.h b/MifareUltralight.h
@@ -12,6 +12,7 @@ class MifareUltralight
         ~MifareUltralight();
         NfcTag read(byte *uid, unsigned int uidLength);
         boolean write(NdefMessage& ndefMessage, byte *uid, unsigned int uidLength);
+        boolean clean();
     private:
         PN532* nfc;
         unsigned int tagCapacity;

diff --git a/NfcAdapter.cpp b/NfcAdapter.cpp
@@ -48,6 +48,14 @@ boolean NfcAdapter::tagPresent(unsigned long timeout)
     return success;
 }
 
+boolean NfcAdapter::erase()
+{
+    boolean success;
+    NdefMessage message = NdefMessage();
+    message.addEmptyRecord();
+    return write(message);
+}
+
 boolean NfcAdapter::format()
 {
     boolean success;
@@ -64,22 +72,35 @@ boolean NfcAdapter::format()
     return success;
 }
 
-boolean NfcAdapter::erase()
+boolean NfcAdapter::clean()
 {
-    boolean success;
-    if (uidLength == 4)
+    uint8_t type = guessTagType();
+
+    if (type == TAG_TYPE_MIFARE_CLASSIC)
     {
+        #ifdef NDEF_DEBUG
+        Serial.println(F("Cleaning Mifare Classic"));
+        #endif
         MifareClassic mifareClassic = MifareClassic(*shield);
-        success = mifareClassic.formatMifare(uid, uidLength);
+        return mifareClassic.formatMifare(uid, uidLength);
+    }
+    else if (type == TAG_TYPE_2)
+    {
+        #ifdef NDEF_DEBUG
+        Serial.println(F("Cleaning Mifare Ultralight"));
+        #endif
+        MifareUltralight ultralight = MifareUltralight(*shield);
+        return ultralight.clean();
     }
     else
     {
-        Serial.print(F("Unsupported Tag. Length is "));Serial.println(uidLength);
-        success = false;
+        Serial.print(F("No driver for card type "));Serial.println(type);
+        return false;
     }
-    return success;
+
 }
 
+
 NfcTag NfcAdapter::read()
 {
     uint8_t type = guessTagType();

diff --git a/NfcAdapter.h b/NfcAdapter.h
@@ -29,8 +29,12 @@ class NfcAdapter {
         boolean tagPresent(unsigned long timeout=0); // tagAvailable
         NfcTag read();
         boolean write(NdefMessage& ndefMessage);
-        boolean erase(); // brings MifareClassic at original state
-        boolean format(); // format MifareClassic to NDEF
+        // erase tag by writing an empty NDEF record
+        boolean erase();
+        // format a tag as NDEF
+        boolean format();
+        // reset tag back to factory state
+        boolean clean();
     private:
         PN532* shield;
         byte uid[7];  // Buffer to store the returned UID