Integrate MiFare ultralight write page function from pull #18 on depr…

…ecated NFCShield_I2C library.

Adafruit_PN532.cpp

@@ -1127,6 +1127,60 @@ uint8_t Adafruit_PN532::mifareultralight_ReadPage (uint8_t page, uint8_t * buffe
   return 1;
 }
 
+/**************************************************************************/
+/*! 
+    Tries to write an entire 4-byte page at the specified block
+    address.
+
+    @param  page          The page number to write.  (0..63 for most cases)
+    @param  data          The byte array that contains the data to write.
+                          Should be exactly 4 bytes long.
+    
+    @returns 1 if everything executed properly, 0 for an error
+*/
+/**************************************************************************/
+uint8_t Adafruit_PN532::mifareultralight_WritePage (uint8_t page, uint8_t * data)
+{
+
+  if (page >= 64)
+  {
+    #ifdef MIFAREDEBUG
+      Serial.println(F("Page value out of range"));
+    #endif
+    // Return Failed Signal
+    return 0;
+  }
+
+  #ifdef MIFAREDEBUG
+    Serial.print(F("Trying to write 4 byte page"));Serial.println(page);
+  #endif
+
+  /* Prepare the first command */
+  pn532_packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
+  pn532_packetbuffer[1] = 1;                      /* Card number */
+  pn532_packetbuffer[2] = MIFARE_ULTRALIGHT_CMD_WRITE;       /* Mifare Ultralight Write command = 0xA2 */
+  pn532_packetbuffer[3] = page;            /* Page Number (0..63 for most cases) */
+  memcpy (pn532_packetbuffer+4, data, 4);          /* Data Payload */
+
+  /* Send the command */
+  if (! sendCommandCheckAck(pn532_packetbuffer, 8))
+  {
+    #ifdef MIFAREDEBUG
+      Serial.println(F("Failed to receive ACK for write command"));
+    #endif
+
+    // Return Failed Signal
+    return 0;
+  }  
+  delay(10);
+
+  /* Read the response packet */
+  readdata(pn532_packetbuffer, 26);
+
+  // Return OK Signal
+  return 1;
+}
+
 
 
 /************** high level communication functions (handles both I2C and SPI) */

Adafruit_PN532.h

@@ -105,6 +105,7 @@
 #define MIFARE_CMD_DECREMENT                (0xC0)
 #define MIFARE_CMD_INCREMENT                (0xC1)
 #define MIFARE_CMD_STORE                    (0xC2)
+#define MIFARE_ULTRALIGHT_CMD_WRITE         (0xA2)
 
 // Prefixes for NDEF Records (to identify record type)
 #define NDEF_URIPREFIX_NONE                 (0x00)
@@ -182,6 +183,7 @@ class Adafruit_PN532{
 
   // Mifare Ultralight functions
   uint8_t mifareultralight_ReadPage (uint8_t page, uint8_t * buffer);
+  uint8_t mifareultralight_WritePage (uint8_t page, uint8_t * data);
 
   // Help functions to display formatted text
   static void PrintHex(const byte * data, const uint32_t numBytes);