Diff: MifareUltralight.cpp

Revision:

3:4189a10038e6

Child:

5:51f820fbd18a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MifareUltralight.cpp	Thu Nov 21 04:30:49 2013 +0000
@@ -0,0 +1,165 @@
+#include "MifareUltralight.h"
+
+#include "PN532_debug.h"
+
+#define ULTRALIGHT_PAGE_SIZE 4
+#define ULTRALIGHT_READ_SIZE 4 // we should be able to read 16 uint8_ts at a time
+
+#define ULTRALIGHT_DATA_START_PAGE 4
+#define ULTRALIGHT_MESSAGE_LENGTH_INDEX 1
+#define ULTRALIGHT_DATA_START_INDEX 2
+#define ULTRALIGHT_MAX_PAGE 63
+
+#define NFC_FORUM_TAG_TYPE_2 ("NFC Forum Type 2")
+
+MifareUltralight::MifareUltralight(PN532& nfcShield)
+{
+    nfc = &nfcShield;
+    ndefStartIndex = 0;
+    messageLength = 0;
+}
+
+MifareUltralight::~MifareUltralight()
+{
+}
+
+NfcTag MifareUltralight::read(uint8_t * uid, unsigned int uidLength)
+{
+    if (isUnformatted())
+    {
+        DMSG("WARNING: Tag is not formatted.");
+        return NfcTag(uid, uidLength, NFC_FORUM_TAG_TYPE_2);
+    }
+
+    readCapabilityContainer(); // meta info for tag
+    findNdefMessage();
+    calculateBufferSize();
+
+    if (messageLength == 0) { // data is 0x44 0x03 0x00 0xFE
+        NdefMessage message = NdefMessage();
+        message.addEmptyRecord();
+        return NfcTag(uid, uidLength, NFC_FORUM_TAG_TYPE_2, message);
+    }
+
+    bool success;
+    uint8_t page;
+    uint8_t index = 0;
+    uint8_t buffer[bufferSize];
+    for (page = ULTRALIGHT_DATA_START_PAGE; page < ULTRALIGHT_MAX_PAGE; page++)
+    {
+        // read the data
+        success = nfc->mifareultralight_ReadPage(page, &buffer[index]);
+        if (success)
+        {
+            #ifdef MIFARE_ULTRALIGHT_DEBUG
+            DMSG("Page ");Serial.print(page);DMSG(" ");
+            nfc->PrintHexChar(&buffer[index], ULTRALIGHT_PAGE_SIZE);
+            #endif
+        }
+        else
+        {
+            DMSG("Read failed ");DMSG_INT(page);
+            // TODO error handling
+            messageLength = 0;
+            break;
+        }
+
+        if (index >= (messageLength + ndefStartIndex))
+        {
+            break;
+        }
+
+        index += ULTRALIGHT_PAGE_SIZE;
+    }
+
+    NdefMessage ndefMessage = NdefMessage(&buffer[ndefStartIndex], messageLength);
+    return NfcTag(uid, uidLength, NFC_FORUM_TAG_TYPE_2, ndefMessage);
+
+}
+
+bool MifareUltralight::isUnformatted()
+{
+    uint8_t page = 4;
+    uint8_t data[ULTRALIGHT_READ_SIZE];
+    bool success = nfc->mifareultralight_ReadPage (page, data);
+    if (success)
+    {
+        return (data[0] == 0xFF && data[1] == 0xFF && data[2] == 0xFF && data[3] == 0xFF);
+    }
+    else
+    {
+        DMSG("Error. Failed read page ");DMSG_INT(page);
+        return false;
+    }
+}
+
+// page 3 has tag capabilities
+void MifareUltralight::readCapabilityContainer()
+{
+    uint8_t data[ULTRALIGHT_PAGE_SIZE];
+    int success = nfc->mifareultralight_ReadPage (3, data);
+    if (success)
+    {
+        // See AN1303 - different rules for Mifare Family uint8_t2 = (additional data + 48)/8
+        tagCapacity = data[2] * 8;
+        #ifdef MIFARE_ULTRALIGHT_DEBUG
+        DMSG("Tag capacity "));Serial.print(tagCapacity);DMSG(F(" uint8_ts");
+        #endif
+
+        // TODO future versions should get lock information
+    }
+}
+
+// read enough of the message to find the ndef message length
+void MifareUltralight::findNdefMessage()
+{
+    int page;
+    uint8_t data[12]; // 3 pages
+    uint8_t* data_ptr = &data[0];
+
+    // the nxp read command reads 4 pages, unfortunately adafruit give me one page at a time
+    bool success = true;
+    for (page = 4; page < 6; page++)
+    {
+        success = success && nfc->mifareultralight_ReadPage(page, data_ptr);
+        #ifdef MIFARE_ULTRALIGHT_DEBUG
+        DMSG("Page "));Serial.print(page);Serial.print(F(" - ");
+        nfc->PrintHexChar(data_ptr, 4);
+        #endif
+        data_ptr += ULTRALIGHT_PAGE_SIZE;
+    }
+
+    if (success)
+    {
+        if (data[0] == 0x03)
+        {
+            messageLength = data[1];
+            ndefStartIndex = 2;
+        }
+        else if (data[5] == 0x3) // page 5 uint8_t 1
+        {
+            // TODO should really read the lock control TLV to ensure uint8_t[5] is correct
+            messageLength = data[6];
+            ndefStartIndex = 7;
+        }
+    }
+
+    #ifdef MIFARE_ULTRALIGHT_DEBUG
+    DMSG("messageLength ");DMSG(messageLength);
+    DMSG("ndefStartIndex ");DMSG(ndefStartIndex);
+    #endif
+}
+
+// buffer is larger than the message, need to handle some data before and after
+// message and need to ensure we read full pages
+void MifareUltralight::calculateBufferSize()
+{
+    // TLV terminator 0xFE is 1 uint8_t
+    bufferSize = messageLength + ndefStartIndex + 1;
+
+    if (bufferSize % ULTRALIGHT_READ_SIZE != 0)
+    {
+        // buffer must be an increment of page size
+        bufferSize = ((bufferSize / ULTRALIGHT_READ_SIZE) + 1) * ULTRALIGHT_READ_SIZE;
+    }
+}