]> git.zerfleddert.de Git - proxmark3-svn/blobdiff - armsrc/hitag2.c
chg: moved to header file
[proxmark3-svn] / armsrc / hitag2.c
index 886e19707825d127a0a786a130fc6d61e51a7f52..0fab407f113af2c63348df04fcf57a2153dcd2c0 100644 (file)
-/*
- * Hitag2 emulation
- * 
- * Contains state and functions for an emulated Hitag2 tag. Offers an entry
- * point to handle commands, needs a callback to send response.
- * 
- * (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
- */
-
-#include <proxmark3.h>
-#include <stdint.h>
+//-----------------------------------------------------------------------------
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Hitag2 emulation (preliminary test version)
+//
+// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
+//-----------------------------------------------------------------------------
+// Hitag2 complete rewrite of the code
+// - Fixed modulation/encoding issues
+// - Rewrote code for transponder emulation
+// - Added snooping of transponder communication
+// - Added reader functionality
+//
+// (c) 2012 Roel Verdult
+//-----------------------------------------------------------------------------
 
+#include "proxmark3.h"
 #include "apps.h"
+#include "util.h"
 #include "hitag2.h"
+#include "string.h"
+#include "BigBuf.h"
 
-struct hitag2_cipher_state {
-       uint64_t state;
-};
+static bool bQuiet;
+static bool bCrypto;
+static bool bAuthenticating;
+static bool bPwd;
+static bool bSuccessful;
 
 struct hitag2_tag {
        uint32_t uid;
-       enum { 
-               TAG_STATE_RESET,          // Just powered up, awaiting GetSnr
-               TAG_STATE_ACTIVATING,     // In activation phase (password mode), sent UID, awaiting reader password
-               TAG_STATE_AUTHENTICATING, // In activation phase (crypto mode), awaiting reader authentication
-               TAG_STATE_ACTIVATED,      // Activation complete, awaiting read/write commands
-               TAG_STATE_WRITING,        // In write command, awaiting sector contents to be written
+       enum {
+               TAG_STATE_RESET      = 0x01,       // Just powered up, awaiting GetSnr
+               TAG_STATE_ACTIVATING = 0x02 ,      // In activation phase (password mode), sent UID, awaiting reader password
+               TAG_STATE_ACTIVATED  = 0x03,       // Activation complete, awaiting read/write commands
+               TAG_STATE_WRITING    = 0x04,       // In write command, awaiting sector contents to be written
        } state;
        unsigned int active_sector;
-       char crypto_active;
-       struct hitag2_cipher_state cs;
-       char sectors[8][4];
+       byte_t crypto_active;
+       uint64_t cs;
+       byte_t sectors[12][4];
 };
 
-static void hitag2_cipher_reset(struct hitag2_tag *tag, const char *challenge);
-static int hitag2_cipher_authenticate(struct hitag2_cipher_state *cs, const char *authenticator);
-static int hitag2_cipher_transcrypt(struct hitag2_cipher_state *cs, char *data, unsigned int bytes, unsigned int bits);
-
-static struct hitag2_tag tag;
-static const struct hitag2_tag resetdata = {
-               .state = TAG_STATE_RESET,
-               .sectors = {                                     // Password mode:               | Crypto mode:
-                               [0] = { 0x35, 0x33, 0x70, 0x11}, // UID                          | UID
-                               [1] = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD                 | 32 bit LSB key
-                               [2] = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved                     | 16 bit MSB key, 16 bit reserved
-                               [3] = { 0x0e, 0xaa, 'H', 'T'},   // Configuration, password TAG  | Configuration, password TAG
-               },
+static struct hitag2_tag tag = {
+    .state = TAG_STATE_RESET,
+    .sectors = {                         // Password mode:               | Crypto mode:
+        [0]  = { 0x02, 0x4e, 0x02, 0x20}, // UID                          | UID
+        [1]  = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD                 | 32 bit LSB key
+        [2]  = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved                     | 16 bit MSB key, 16 bit reserved
+        [3]  = { 0x0e, 0xaa, 0x48, 0x54}, // Configuration, password TAG  | Configuration, password TAG
+        [4]  = { 0x46, 0x5f, 0x4f, 0x4b}, // Data: F_OK
+        [5]  = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU
+        [6]  = { 0xaa, 0xaa, 0xaa, 0xaa}, // Data: ....
+        [7]  = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU
+        [8]  = { 0x00, 0x00, 0x00, 0x00}, // RSK Low
+        [9]  = { 0x00, 0x00, 0x00, 0x00}, // RSK High
+        [10] = { 0x00, 0x00, 0x00, 0x00}, // RCF
+        [11] = { 0x00, 0x00, 0x00, 0x00}, // SYNC
+    },
 };
 
-int hitag2_reset(void)
-{
-       tag.state = TAG_STATE_RESET;
-       tag.crypto_active = 0;
-       return 0;
-}
-
-int hitag2_init(void)
-{
-       memcpy(&tag, &resetdata, sizeof(tag));
-       hitag2_reset();
-       return 0;
-}
-
-int hitag2_handle_command(const char* data, const int length, hitag2_response_callback_t cb, void *cb_cookie)
-{
-       (void)data; (void)length; (void)cb; (void)cb_cookie;
-       int retry = 0, done = 0, result=0;
-       char temp[10];
-
-       if(tag.crypto_active && length < sizeof(temp)*8) {
-               /* Decrypt command */
-               memcpy(temp, data, (length+7)/8);
-               hitag2_cipher_transcrypt(&(tag.cs), temp, length/8, length%8);
-               data = temp;
-       }
+// ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces. 
+// Historically it used to be FREE_BUFFER_SIZE, which was 2744.
+#define AUTH_TABLE_LENGTH 2744
+static byte_t* auth_table;
+static size_t auth_table_pos = 0;
+static size_t auth_table_len = AUTH_TABLE_LENGTH;
 
-       
-handle_command_retry:
-       switch(tag.state) {
-       case TAG_STATE_RESET:
-               if(length == 5 && data[0] == 0xC0) {
-                       /* Received 11000 from the reader, request for UID, send UID */
-                       result=cb(tag.sectors[0], sizeof(tag.sectors[0])*8, 208, cb_cookie);
-                       done=1;
-                       if(tag.sectors[3][0] & 0x08) {
-                               tag.state=TAG_STATE_AUTHENTICATING;
-                       } else {
-                               tag.state=TAG_STATE_ACTIVATING;
-                       }
-               }
-               break;
-       case TAG_STATE_ACTIVATING:
-               if(length == 0x20) {
-                       /* Received RWD password, respond with configuration and our password */
-                       result=cb(tag.sectors[3], sizeof(tag.sectors[3])*8, 208, cb_cookie);
-                       done=1;
-                       tag.state=TAG_STATE_ACTIVATED;
-               }
-               break;
-       case TAG_STATE_AUTHENTICATING:
-               if(length == 0x40) {
-                       /* Received initialisation vector || authentication token, fire up cipher, send our password */
-                       hitag2_cipher_reset(&tag, data);
-                       if(hitag2_cipher_authenticate(&(tag.cs), data+4)) {
-                               char response_enc[4];
-                               memcpy(response_enc, tag.sectors[3], 4);
-                               hitag2_cipher_transcrypt(&(tag.cs), response_enc, 4, 0);
-                               result=cb(response_enc, 4*8, 208, cb_cookie);
-                               done=1;
-                               tag.crypto_active = 1;
-                               tag.state = TAG_STATE_ACTIVATED;
-                       } else {
-                               /* The reader failed to authenticate, do nothing */
-                               DbpString("Reader authentication failed");
-                       }
-               }
-               break;
-       case TAG_STATE_ACTIVATED:
-               if(length == 10) {
-                       if( ((data[0] & 0xC0) == 0xC0) && ((data[0] & 0x06) == 0) ) {
-                               /* Read command: 11xx x00y  yy with yyy == ~xxx, xxx is sector number */
-                               unsigned int sector = (~( ((data[0]<<2)&0x04) | ((data[1]>>6)&0x03) ) & 0x07);
-                               if(sector == ( (data[0]>>3)&0x07 ) ) {
-                                       memcpy(temp, tag.sectors[sector], 4);
-                                       if(tag.crypto_active) {
-                                               hitag2_cipher_transcrypt(&(tag.cs), temp, 4, 0);
-                                       }
-                                       /* Respond with contents of sector sector */
-                                       result = cb(temp, 4*8, 208, cb_cookie);
-                                       done=1;
-                               } else {
-                                       /* transmission error */
-                                       DbpString("Transmission error (read) in activated state");
-                               }
-                       } else if( ((data[0] & 0xC0) == 0x80) && ((data[0] & 0x06) == 2) ) {
-                               /* Write command: 10xx x01y  yy with yyy == ~xxx, xxx is sector number */
-                               unsigned int sector = (~( ((data[0]<<2)&0x04) | ((data[1]>>6)&0x03) ) & 0x07);
-                               if(sector == ( (data[0]>>3)&0x07 ) ) {
-                                       /* Prepare write, acknowledge by repeating command */
-                                       if(tag.crypto_active) {
-                                               hitag2_cipher_transcrypt(&(tag.cs), temp, length/8, length%8);
-                                       }
-                                       result = cb(data, length, 208, cb_cookie);
-                                       done=1;
-                                       tag.active_sector = sector;
-                                       tag.state=TAG_STATE_WRITING;
-                               } else {
-                                       /* transmission error */
-                                       DbpString("Transmission error (write) in activated state");
-                               }
-                       } 
-                               
-               }
-       case TAG_STATE_WRITING:
-               if(length == 32) {
-                       /* These are the sector contents to be written. We don't have to do anything else. */
-                       memcpy(tag.sectors[tag.active_sector], data, length/8);
-                       tag.state=TAG_STATE_ACTIVATED;
-                       done=1;
-               }
-       }
-       
-       if(!done && !retry) {
-               /* We didn't respond, maybe our state is faulty. Reset and try again. */
-               retry=1;
-               if(tag.crypto_active) {
-                       /* Restore undeciphered data */
-                       memcpy(temp, data, (length+7)/8);
-               }
-               hitag2_reset();
-               goto handle_command_retry;
-       }
-
-       return result;
-}
+static byte_t password[4];
+static byte_t NrAr[8];
+static byte_t key[8];
+static uint64_t cipher_state;
 
 /* Following is a modified version of cryptolib.com/ciphers/hitag2/ */
 // Software optimized 48-bit Philips/NXP Mifare Hitag2 PCF7936/46/47/52 stream cipher algorithm by I.C. Wiener 2006-2007.
@@ -195,7 +94,6 @@ handle_command_retry:
 #define rotl64(x, n)   ((((u64)(x))<<((n)&63))+(((u64)(x))>>((0-(n))&63)))
 
 // Single bit Hitag2 functions:
-
 #define i4(x,a,b,c,d)  ((u32)((((x)>>(a))&1)+(((x)>>(b))&1)*2+(((x)>>(c))&1)*4+(((x)>>(d))&1)*8))
 
 static const u32 ht2_f4a = 0x2C79;             // 0010 1100 0111 1001
@@ -204,22 +102,22 @@ static const u32 ht2_f5c = 0x7907287B;    // 0111 1001 0000 0111 0010 1000 0111 101
 
 static u32 _f20 (const u64 x)
 {
-       u32                                     i5;
-       
+       u32     i5;
+
        i5 = ((ht2_f4a >> i4 (x, 1, 2, 4, 5)) & 1)* 1
           + ((ht2_f4b >> i4 (x, 7,11,13,14)) & 1)* 2
           + ((ht2_f4b >> i4 (x,16,20,22,25)) & 1)* 4
           + ((ht2_f4b >> i4 (x,27,28,30,32)) & 1)* 8
           + ((ht2_f4a >> i4 (x,33,42,43,45)) & 1)*16;
-       
+
        return (ht2_f5c >> i5) & 1;
 }
 
 static u64 _hitag2_init (const u64 key, const u32 serial, const u32 IV)
 {
-       u32                                     i;
-       u64                                     x = ((key & 0xFFFF) << 32) + serial;
-       
+       u32     i;
+       u64     x = ((key & 0xFFFF) << 32) + serial;
+
        for (i = 0; i < 32; i++)
        {
                x >>= 1;
@@ -230,62 +128,1321 @@ static u64 _hitag2_init (const u64 key, const u32 serial, const u32 IV)
 
 static u64 _hitag2_round (u64 *state)
 {
-       u64                                     x = *state;
-       
+       u64 x = *state;
+
        x = (x >>  1) +
         ((((x >>  0) ^ (x >>  2) ^ (x >>  3) ^ (x >>  6)
          ^ (x >>  7) ^ (x >>  8) ^ (x >> 16) ^ (x >> 22)
          ^ (x >> 23) ^ (x >> 26) ^ (x >> 30) ^ (x >> 41)
          ^ (x >> 42) ^ (x >> 43) ^ (x >> 46) ^ (x >> 47)) & 1) << 47);
-       
+
        *state = x;
        return _f20 (x);
 }
 
+// "MIKRON"             =  O  N  M  I  K  R
+// Key                  = 4F 4E 4D 49 4B 52             - Secret 48-bit key
+// Serial               = 49 43 57 69                   - Serial number of the tag, transmitted in clear
+// Random               = 65 6E 45 72                   - Random IV, transmitted in clear
+//~28~DC~80~31  = D7 23 7F CE                   - Authenticator value = inverted first 4 bytes of the keystream
+
+// The code below must print out "D7 23 7F CE 8C D0 37 A9 57 49 C1 E6 48 00 8A B6".
+// The inverse of the first 4 bytes is sent to the tag to authenticate.
+// The rest is encrypted by XORing it with the subsequent keystream.
+
 static u32 _hitag2_byte (u64 * x)
 {
-       u32                                     i, c;
-       
+       u32     i, c;
+
        for (i = 0, c = 0; i < 8; i++) c += (u32) _hitag2_round (x) << (i^7);
        return c;
 }
 
+static int hitag2_reset(void) {
+       tag.state = TAG_STATE_RESET;
+       tag.crypto_active = 0;
+       return 0;
+}
 
-/* Cipher/tag glue code: */
+static int hitag2_init(void) {
+       hitag2_reset();
+       return 0;
+}
 
-static void hitag2_cipher_reset(struct hitag2_tag *tag, const char *iv)
+static void hitag2_cipher_reset(struct hitag2_tag *tag, const byte_t *iv)
 {
-       uint64_t key = ((uint64_t)tag->sectors[2][2]) |
-                       ((uint64_t)tag->sectors[2][3] << 8) |
-                       ((uint64_t)tag->sectors[1][0] << 16) |
-                       ((uint64_t)tag->sectors[1][1] << 24) |
-                       ((uint64_t)tag->sectors[1][2] << 32) |
-                       ((uint64_t)tag->sectors[1][3] << 40);
-       uint32_t uid = ((uint32_t)tag->sectors[0][0]) |
-                       ((uint32_t)tag->sectors[0][1] << 8) |
-                       ((uint32_t)tag->sectors[0][2] << 16) |
-                       ((uint32_t)tag->sectors[0][3] << 24);
+       uint64_t key =  ((uint64_t)tag->sectors[2][2]) |
+                  ((uint64_t)tag->sectors[2][3] << 8) |
+                  ((uint64_t)tag->sectors[1][0] << 16) |
+                  ((uint64_t)tag->sectors[1][1] << 24) |
+                  ((uint64_t)tag->sectors[1][2] << 32) |
+                  ((uint64_t)tag->sectors[1][3] << 40);
+       uint32_t uid =  ((uint32_t)tag->sectors[0][0]) |
+                  ((uint32_t)tag->sectors[0][1] << 8) |
+                  ((uint32_t)tag->sectors[0][2] << 16) |
+                  ((uint32_t)tag->sectors[0][3] << 24);
        uint32_t iv_ = (((uint32_t)(iv[0]))) |
                        (((uint32_t)(iv[1])) << 8) |
                        (((uint32_t)(iv[2])) << 16) |
                        (((uint32_t)(iv[3])) << 24);
-       tag->cs.state = _hitag2_init(rev64(key), rev32(uid), rev32(iv_));
+       tag->cs = _hitag2_init(rev64(key), rev32(uid), rev32(iv_));
 }
 
-static int hitag2_cipher_authenticate(struct hitag2_cipher_state *cs, const char *authenticator_is)
+static int hitag2_cipher_authenticate(uint64_t* cs, const byte_t *authenticator_is)
 {
-       char authenticator_should[4];
-       authenticator_should[0] = ~_hitag2_byte(&(cs->state));
-       authenticator_should[1] = ~_hitag2_byte(&(cs->state));
-       authenticator_should[2] = ~_hitag2_byte(&(cs->state));
-       authenticator_should[3] = ~_hitag2_byte(&(cs->state));
-       return memcmp(authenticator_should, authenticator_is, 4) == 0;
+       byte_t authenticator_should[4];
+       authenticator_should[0] = ~_hitag2_byte(cs);
+       authenticator_should[1] = ~_hitag2_byte(cs);
+       authenticator_should[2] = ~_hitag2_byte(cs);
+       authenticator_should[3] = ~_hitag2_byte(cs);
+       return (memcmp(authenticator_should, authenticator_is, 4) == 0);
 }
 
-static int hitag2_cipher_transcrypt(struct hitag2_cipher_state *cs, char *data, unsigned int bytes, unsigned int bits)
+static int hitag2_cipher_transcrypt(uint64_t* cs, byte_t *data, unsigned int bytes, unsigned int bits)
 {
        int i;
-       for(i=0; i<bytes; i++) data[i] ^= _hitag2_byte(&(cs->state));
-       for(i=0; i<bits; i++) data[bytes] ^= _hitag2_round(&(cs->state)) << (7-i);
+       for(i=0; i<bytes; i++) data[i] ^= _hitag2_byte(cs);
+       for(i=0; i<bits; i++) data[bytes] ^= _hitag2_round(cs) << (7-i);
        return 0;
 }
+
+// Sam7s has several timers, we will use the source TIMER_CLOCK1 (aka AT91C_TC_CLKS_TIMER_DIV1_CLOCK)
+// TIMER_CLOCK1 = MCK/2, MCK is running at 48 MHz, Timer is running at 48/2 = 24 MHz
+// Hitag units (T0) have duration of 8 microseconds (us), which is 1/125000 per second (carrier)
+// T0 = TIMER_CLOCK1 / 125000 = 192
+#define T0 192
+
+#define SHORT_COIL()   LOW(GPIO_SSC_DOUT)
+#define OPEN_COIL()            HIGH(GPIO_SSC_DOUT)
+
+#define HITAG_FRAME_LEN 20
+#define HITAG_T_STOP  36 /* T_EOF should be > 36 */
+#define HITAG_T_LOW            8  /* T_LOW should be 4..10 */
+#define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */
+#define HITAG_T_1_MIN 25 /* T[1] should be 26..30 */
+//#define HITAG_T_EOF   40 /* T_EOF should be > 36 */
+#define HITAG_T_EOF   80        /* T_EOF should be > 36 */
+#define HITAG_T_WAIT_1 200 /* T_wresp should be 199..206 */
+#define HITAG_T_WAIT_2 90 /* T_wresp should be 199..206 */
+#define HITAG_T_WAIT_MAX 300 /* bit more than HITAG_T_WAIT_1 + HITAG_T_WAIT_2 */
+
+#define HITAG_T_TAG_ONE_HALF_PERIOD            10
+#define HITAG_T_TAG_TWO_HALF_PERIOD            25
+#define HITAG_T_TAG_THREE_HALF_PERIOD  41 
+#define HITAG_T_TAG_FOUR_HALF_PERIOD   57 
+
+#define HITAG_T_TAG_HALF_PERIOD                        16
+#define HITAG_T_TAG_FULL_PERIOD                        32
+
+#define HITAG_T_TAG_CAPTURE_ONE_HALF   13
+#define HITAG_T_TAG_CAPTURE_TWO_HALF   25
+#define HITAG_T_TAG_CAPTURE_THREE_HALF 41 
+#define HITAG_T_TAG_CAPTURE_FOUR_HALF   57 
+
+
+static void hitag_send_bit(int bit) {
+       LED_A_ON();
+       // Reset clock for the next bit 
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
+       
+       // Fixed modulation, earlier proxmark version used inverted signal
+       if(bit == 0) {
+               // Manchester: Unloaded, then loaded |__--|
+               LOW(GPIO_SSC_DOUT);
+               while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD);
+               HIGH(GPIO_SSC_DOUT);
+               while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD);
+       } else {
+               // Manchester: Loaded, then unloaded |--__|
+               HIGH(GPIO_SSC_DOUT);
+               while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD);
+               LOW(GPIO_SSC_DOUT);
+               while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD);
+       }
+       LED_A_OFF();
+}
+
+static void hitag_send_frame(const byte_t* frame, size_t frame_len)
+{
+       // Send start of frame
+       for(size_t i=0; i<5; i++) {
+               hitag_send_bit(1);
+       }
+
+       // Send the content of the frame
+       for(size_t i=0; i<frame_len; i++) {
+               hitag_send_bit((frame[i/8] >> (7-(i%8)))&1);
+       }
+
+       // Drop the modulation
+       LOW(GPIO_SSC_DOUT);
+}
+
+
+static void hitag2_handle_reader_command(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen)
+{
+       byte_t rx_air[HITAG_FRAME_LEN];
+       
+       // Copy the (original) received frame how it is send over the air
+       memcpy(rx_air,rx,nbytes(rxlen));
+
+       if(tag.crypto_active) {
+               hitag2_cipher_transcrypt(&(tag.cs),rx,rxlen/8,rxlen%8);
+       }
+       
+       // Reset the transmission frame length 
+       *txlen = 0;
+       
+       // Try to find out which command was send by selecting on length (in bits)
+       switch (rxlen) {
+               // Received 11000 from the reader, request for UID, send UID 
+               case 05: {
+                       // Always send over the air in the clear plaintext mode
+                       if(rx_air[0] != 0xC0) {
+                               // Unknown frame ?
+                               return;
+                       }
+                       *txlen = 32;
+                       memcpy(tx,tag.sectors[0],4);
+                       tag.crypto_active = 0;
+               }
+               break;
+
+               // Read/Write command: ..xx x..y  yy with yyy == ~xxx, xxx is sector number 
+               case 10: {
+                       unsigned int sector = (~( ((rx[0]<<2)&0x04) | ((rx[1]>>6)&0x03) ) & 0x07);
+                       // Verify complement of sector index
+                       if(sector != ((rx[0]>>3)&0x07)) {
+                               //DbpString("Transmission error (read/write)");
+                               return;
+                       }
+
+                       switch (rx[0] & 0xC6) {
+                               // Read command: 11xx x00y
+                               case 0xC0:
+                                       memcpy(tx,tag.sectors[sector],4);
+                                       *txlen = 32;
+                               break;
+                                       
+                                // Inverted Read command: 01xx x10y
+                               case 0x44:
+                                       for (size_t i=0; i<4; i++) {
+                                               tx[i] = tag.sectors[sector][i] ^ 0xff;
+                                       }
+                                       *txlen = 32;
+                               break;
+
+                               // Write command: 10xx x01y
+                               case 0x82:
+                                       // Prepare write, acknowledge by repeating command
+                                       memcpy(tx,rx,nbytes(rxlen));
+                                       *txlen = rxlen;
+                                       tag.active_sector = sector;
+                                       tag.state=TAG_STATE_WRITING;
+                               break;
+                               
+                               // Unknown command
+                               default:
+                                       Dbprintf("Uknown command: %02x %02x",rx[0],rx[1]);
+                                       return;
+                               break;
+                       }
+               }
+               break;
+
+               // Writing data or Reader password
+               case 32: {
+                       if(tag.state == TAG_STATE_WRITING) {
+                               // These are the sector contents to be written. We don't have to do anything else.
+                               memcpy(tag.sectors[tag.active_sector],rx,nbytes(rxlen));
+                               tag.state=TAG_STATE_RESET;
+                               return;
+                       } else {
+                               // Received RWD password, respond with configuration and our password
+                               if(memcmp(rx,tag.sectors[1],4) != 0) {
+                                       DbpString("Reader password is wrong");
+                                       return;
+                               }
+                               *txlen = 32;
+                               memcpy(tx,tag.sectors[3],4);
+                       }
+               }
+               break;
+
+               // Received RWD authentication challenge and respnse
+               case 64: {
+                       // Store the authentication attempt
+                       if (auth_table_len < (AUTH_TABLE_LENGTH-8)) {
+                               memcpy(auth_table+auth_table_len,rx,8);
+                               auth_table_len += 8;
+                       }
+
+                       // Reset the cipher state
+                       hitag2_cipher_reset(&tag,rx);
+                       // Check if the authentication was correct
+                       if(!hitag2_cipher_authenticate(&(tag.cs),rx+4)) {
+                               // The reader failed to authenticate, do nothing
+                               Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]);
+                               return;
+                       }
+                       // Succesful, but commented out reporting back to the Host, this may delay to much.
+                       // Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]);
+
+                       // Activate encryption algorithm for all further communication
+                       tag.crypto_active = 1;
+
+                       // Use the tag password as response
+                       memcpy(tx,tag.sectors[3],4);
+                       *txlen = 32;
+               }
+               break;
+       }
+
+//     LogTraceHitag(rx,rxlen,0,0,false);
+//     LogTraceHitag(tx,*txlen,0,0,true);
+       
+       if(tag.crypto_active) {
+               hitag2_cipher_transcrypt(&(tag.cs), tx, *txlen/8, *txlen%8);
+       }
+}
+
+static void hitag_reader_send_bit(int bit) {
+       LED_A_ON();
+       // Reset clock for the next bit 
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
+       
+       // Binary puls length modulation (BPLM) is used to encode the data stream
+       // This means that a transmission of a one takes longer than that of a zero
+       
+       // Enable modulation, which means, drop the field
+       HIGH(GPIO_SSC_DOUT);
+       
+       // Wait for 4-10 times the carrier period
+       while(AT91C_BASE_TC0->TC_CV < T0*6);
+       //      SpinDelayUs(8*8);
+       
+       // Disable modulation, just activates the field again
+       LOW(GPIO_SSC_DOUT);
+       
+       if(bit == 0) {
+               // Zero bit: |_-|
+               while(AT91C_BASE_TC0->TC_CV < T0*22);
+
+       } else {
+               // One bit: |_--|
+               while(AT91C_BASE_TC0->TC_CV < T0*28);
+       }
+       LED_A_OFF();
+}
+
+
+static void hitag_reader_send_frame(const byte_t* frame, size_t frame_len)
+{
+       // Send the content of the frame
+       for(size_t i=0; i<frame_len; i++) {
+               hitag_reader_send_bit((frame[i/8] >> (7-(i%8)))&1);
+       }
+       // Send EOF 
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
+       // Enable modulation, which means, drop the field
+       HIGH(GPIO_SSC_DOUT);
+       // Wait for 4-10 times the carrier period
+       while(AT91C_BASE_TC0->TC_CV < T0*6);
+       // Disable modulation, just activates the field again
+       LOW(GPIO_SSC_DOUT);
+}
+
+size_t blocknr;
+
+static bool hitag2_password(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
+       // Reset the transmission frame length
+       *txlen = 0;
+       
+       // Try to find out which command was send by selecting on length (in bits)
+       switch (rxlen) {
+               // No answer, try to resurrect
+               case 0: {
+                       // Stop if there is no answer (after sending password)
+                       if (bPwd) {
+                               DbpString("Password failed!");
+                               return false;
+                       }
+                       *txlen = 5;
+                       memcpy(tx,"\xc0",nbytes(*txlen));
+               } break;
+                       
+               // Received UID, tag password
+               case 32: {
+                       if (!bPwd) {
+                               *txlen = 32;
+                               memcpy(tx,password,4);
+                               bPwd = true;
+                               memcpy(tag.sectors[blocknr],rx,4);
+                               blocknr++;
+                       } else {
+                               
+                               if(blocknr == 1){
+                                       //store password in block1, the TAG answers with Block3, but we need the password in memory
+                                       memcpy(tag.sectors[blocknr],tx,4);
+                               } else {
+                                       memcpy(tag.sectors[blocknr],rx,4);
+                               }
+                               
+                               blocknr++;
+                               if (blocknr > 7) {
+                                       DbpString("Read succesful!");
+                                       bSuccessful = true;
+                                       return false;
+                               }
+                               *txlen = 10;
+                               tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2);
+                               tx[1] = ((blocknr^7) << 6);
+                       }
+               } break;
+                       
+               // Unexpected response
+    default: {
+                       Dbprintf("Uknown frame length: %d",rxlen);
+                       return false;
+               } break;
+       }
+       return true;
+}
+
+static bool hitag2_crypto(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
+       // Reset the transmission frame length
+       *txlen = 0;
+       
+  if(bCrypto) {
+               hitag2_cipher_transcrypt(&cipher_state,rx,rxlen/8,rxlen%8);
+       }
+
+       // Try to find out which command was send by selecting on length (in bits)
+       switch (rxlen) {
+      // No answer, try to resurrect
+               case 0: {
+                       // Stop if there is no answer while we are in crypto mode (after sending NrAr)
+                       if (bCrypto) {
+        // Failed during authentication
+        if (bAuthenticating) {
+          DbpString("Authentication failed!");
+          return false;
+        } else {
+          // Failed reading a block, could be (read/write) locked, skip block and re-authenticate
+          if (blocknr == 1) {
+            // Write the low part of the key in memory
+            memcpy(tag.sectors[1],key+2,4);
+          } else if (blocknr == 2) {
+            // Write the high part of the key in memory
+            tag.sectors[2][0] = 0x00;
+            tag.sectors[2][1] = 0x00;
+            tag.sectors[2][2] = key[0];
+            tag.sectors[2][3] = key[1];
+          } else {
+            // Just put zero's in the memory (of the unreadable block)
+            memset(tag.sectors[blocknr],0x00,4);
+          }
+          blocknr++;
+          bCrypto = false;
+        }
+                       } else {
+                               *txlen = 5;
+                               memcpy(tx,"\xc0",nbytes(*txlen));
+                       }
+               } break;
+                       
+      // Received UID, crypto tag answer
+               case 32: {
+                       if (!bCrypto) {
+        uint64_t ui64key = key[0] | ((uint64_t)key[1]) << 8 | ((uint64_t)key[2]) << 16 | ((uint64_t)key[3]) << 24 | ((uint64_t)key[4]) << 32 | ((uint64_t)key[5]) << 40;
+        uint32_t ui32uid = rx[0] | ((uint32_t)rx[1]) << 8 | ((uint32_t)rx[2]) << 16 | ((uint32_t)rx[3]) << 24;
+        cipher_state = _hitag2_init(rev64(ui64key), rev32(ui32uid), 0);
+        memset(tx,0x00,4);
+        memset(tx+4,0xff,4);
+        hitag2_cipher_transcrypt(&cipher_state,tx+4,4,0);
+                               *txlen = 64;
+                               bCrypto = true;
+                               bAuthenticating = true;
+                       } else {
+        // Check if we received answer tag (at)
+        if (bAuthenticating) {
+                       bAuthenticating = false;
+        } else {
+                       // Store the received block
+                       memcpy(tag.sectors[blocknr],rx,4);
+                       blocknr++;
+        }
+        if (blocknr > 7) {
+                       DbpString("Read succesful!");
+                       bSuccessful = true;
+                       return false;
+        }
+        *txlen = 10;
+        tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2);
+        tx[1] = ((blocknr^7) << 6);
+                       }
+               } break;
+                       
+      // Unexpected response
+               default: {
+                       Dbprintf("Uknown frame length: %d",rxlen);
+                       return false;
+               } break;
+       }
+       
+  
+       if(bCrypto) {
+               // We have to return now to avoid double encryption
+               if (!bAuthenticating) {
+                 hitag2_cipher_transcrypt(&cipher_state, tx, *txlen/8, *txlen%8);
+               }
+       }
+
+       return true;
+}
+
+
+static bool hitag2_authenticate(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
+       // Reset the transmission frame length 
+       *txlen = 0;
+       
+       // Try to find out which command was send by selecting on length (in bits)
+       switch (rxlen) {
+               // No answer, try to resurrect
+               case 0: {
+                       // Stop if there is no answer while we are in crypto mode (after sending NrAr)
+                       if (bCrypto) {
+                               DbpString("Authentication failed!");
+                               return false;
+                       }
+                       *txlen = 5;
+                       memcpy(tx,"\xc0",nbytes(*txlen));
+               } break;
+                       
+               // Received UID, crypto tag answer
+               case 32: {
+                       if (!bCrypto) {
+                               *txlen = 64;
+                               memcpy(tx,NrAr,8);
+                               bCrypto = true;
+                       } else {
+                               DbpString("Authentication succesful!");
+                               return true;
+                       }
+               } break;
+                       
+               // Unexpected response
+               default: {
+                       Dbprintf("Uknown frame length: %d",rxlen);
+                       return false;
+               } break;
+       }
+       
+       return true;
+}
+
+
+static bool hitag2_test_auth_attempts(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
+
+       // Reset the transmission frame length 
+       *txlen = 0;
+       
+       // Try to find out which command was send by selecting on length (in bits)
+       switch (rxlen) {
+                       // No answer, try to resurrect
+               case 0: {
+                       // Stop if there is no answer while we are in crypto mode (after sending NrAr)
+                       if (bCrypto) {
+                               Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed, removed entry!",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]);
+
+                               // Removing failed entry from authentiations table
+                               memcpy(auth_table+auth_table_pos,auth_table+auth_table_pos+8,8);
+                               auth_table_len -= 8;
+
+                               // Return if we reached the end of the authentications table
+                               bCrypto = false;
+                               if (auth_table_pos == auth_table_len) {
+                                       return false;
+                               }
+
+                               // Copy the next authentication attempt in row (at the same position, b/c we removed last failed entry)
+                               memcpy(NrAr,auth_table+auth_table_pos,8);
+                       }
+                       *txlen = 5;
+                       memcpy(tx,"\xc0",nbytes(*txlen));
+               }       break;
+                       
+                       // Received UID, crypto tag answer, or read block response
+               case 32: {
+                       if (!bCrypto) {
+                               *txlen = 64;
+                               memcpy(tx,NrAr,8);
+                               bCrypto = true;
+                       } else {
+                               Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]);
+                               bCrypto = false;
+                               if ((auth_table_pos+8) == auth_table_len) {
+                                       return false;
+                               }
+                               auth_table_pos += 8;
+                               memcpy(NrAr,auth_table+auth_table_pos,8);
+                       }
+               } break;
+                       
+               default: {
+                       Dbprintf("Uknown frame length: %d",rxlen);
+                       return false;
+               } break;
+       }
+       
+       return true;
+}
+
+static bool hitag2_read_uid(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
+       // Reset the transmission frame length
+       *txlen = 0;
+
+       // Try to find out which command was send by selecting on length (in bits)
+       switch (rxlen) {
+               // No answer, try to resurrect
+               case 0: {
+                       // Just starting or if there is no answer
+                       *txlen = 5;
+                       memcpy(tx,"\xc0",nbytes(*txlen));
+               } break;
+               // Received UID
+               case 32: {
+                       // Check if we received answer tag (at)
+                       if (bAuthenticating) {
+                               bAuthenticating = false;
+                       } else {
+                               // Store the received block
+                               memcpy(tag.sectors[blocknr],rx,4);
+                               blocknr++;
+                       }
+                       if (blocknr > 0) {
+                               //DbpString("Read successful!");
+                               bSuccessful = true;
+                               return false;
+                       }
+               } break;
+               // Unexpected response
+               default: {
+                       Dbprintf("Uknown frame length: %d",rxlen);
+                       return false;
+               } break;
+       }
+       return true;
+}
+
+void SnoopHitag(uint32_t type) {
+       int frame_count;
+       int response;
+       int overflow;
+       bool rising_edge;
+       bool reader_frame;
+       int lastbit;
+       bool bSkip;
+       int tag_sof;
+       byte_t rx[HITAG_FRAME_LEN];
+       size_t rxlen=0;
+       
+       FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+       
+       // free eventually allocated BigBuf memory
+       BigBuf_free(); BigBuf_Clear_ext(false);
+       
+       // Clean up trace and prepare it for storing frames
+       clear_trace();
+       set_tracing(TRUE);
+       
+       auth_table_len = 0;
+       auth_table_pos = 0;
+
+    auth_table = (byte_t *)BigBuf_malloc(AUTH_TABLE_LENGTH);
+       memset(auth_table, 0x00, AUTH_TABLE_LENGTH);
+       
+       DbpString("Starting Hitag2 snoop");
+       LED_D_ON();
+       
+       // Set up eavesdropping mode, frequency divisor which will drive the FPGA
+       // and analog mux selection.
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT  | FPGA_LF_EDGE_DETECT_TOGGLE_MODE);
+       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+       SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+       RELAY_OFF();
+       
+       // Configure output pin that is connected to the FPGA (for modulating)
+       AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+       AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
+
+       // Disable modulation, we are going to eavesdrop, not modulate ;)
+       LOW(GPIO_SSC_DOUT);
+       
+       // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames
+       AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
+       AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
+       
+       // Disable timer during configuration   
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+       
+       // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
+       // external trigger rising edge, load RA on rising edge of TIOA.
+       uint32_t t1_channel_mode = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_BOTH | AT91C_TC_ABETRG | AT91C_TC_LDRA_BOTH;
+       AT91C_BASE_TC1->TC_CMR = t1_channel_mode;
+       
+       // Enable and reset counter
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       
+       // Reset the received frame, frame count and timing info
+       memset(rx,0x00,sizeof(rx));
+       frame_count = 0;
+       response = 0;
+       overflow = 0;
+       reader_frame = false;
+       lastbit = 1;
+       bSkip = true;
+       tag_sof = 4;
+       
+       while(!BUTTON_PRESS() && !usb_poll_validate_length()) {
+               // Watchdog hit
+               WDT_HIT();
+               
+               // Receive frame, watch for at most T0*EOF periods
+               while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) {
+                       // Check if rising edge in modulation is detected
+                       if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
+                               // Retrieve the new timing values 
+                               int ra = (AT91C_BASE_TC1->TC_RA/T0);
+                               
+                               // Find out if we are dealing with a rising or falling edge
+                               rising_edge = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME) > 0;
+
+                               // Shorter periods will only happen with reader frames
+                               if (!reader_frame && rising_edge && ra < HITAG_T_TAG_CAPTURE_ONE_HALF) {
+                                       // Switch from tag to reader capture
+                                       LED_C_OFF();
+                                       reader_frame = true;
+                                       memset(rx,0x00,sizeof(rx));
+                                       rxlen = 0;
+                               }
+                               
+                               // Only handle if reader frame and rising edge, or tag frame and falling edge
+                               if (reader_frame != rising_edge) {
+                                 overflow += ra;
+                                       continue;
+                               }
+                               
+                               // Add the buffered timing values of earlier captured edges which were skipped
+                               ra += overflow;
+                               overflow = 0;
+                               
+                               if (reader_frame) {
+                                       LED_B_ON();
+                                       // Capture reader frame
+                                       if(ra >= HITAG_T_STOP) {
+                                               if (rxlen != 0) {
+                                                       //DbpString("wierd0?");
+                                               }
+                                               // Capture the T0 periods that have passed since last communication or field drop (reset)
+                                               response = (ra - HITAG_T_LOW);
+                                       } else if(ra >= HITAG_T_1_MIN ) {
+                                               // '1' bit 
+                                               rx[rxlen / 8] |= 1 << (7-(rxlen%8));
+                                               rxlen++;
+                                       } else if(ra >= HITAG_T_0_MIN) {
+                                               // '0' bit 
+                                               rx[rxlen / 8] |= 0 << (7-(rxlen%8));
+                                               rxlen++;
+                                       } else {
+                                               // Ignore wierd value, is to small to mean anything
+                                       }
+                               } else {
+                                       LED_C_ON();
+                                       // Capture tag frame (manchester decoding using only falling edges)
+                                       if(ra >= HITAG_T_EOF) {
+                                               if (rxlen != 0) {
+                                                       //DbpString("wierd1?");
+                                               }
+                                               // Capture the T0 periods that have passed since last communication or field drop (reset)
+                                               // We always recieve a 'one' first, which has the falling edge after a half period |-_|
+                                               response = ra-HITAG_T_TAG_HALF_PERIOD;
+                                       } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
+                                               // Manchester coding example |-_|_-|-_| (101)
+                                               rx[rxlen / 8] |= 0 << (7-(rxlen%8));
+                                               rxlen++;
+                                               rx[rxlen / 8] |= 1 << (7-(rxlen%8));
+                                               rxlen++;
+                                       } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
+                                               // Manchester coding example |_-|...|_-|-_| (0...01)
+                                               rx[rxlen / 8] |= 0 << (7-(rxlen%8));
+                                               rxlen++;
+                                               // We have to skip this half period at start and add the 'one' the second time 
+                                               if (!bSkip) {
+                                                       rx[rxlen / 8] |= 1 << (7-(rxlen%8));
+                                                       rxlen++;
+                                               }
+                                               lastbit = !lastbit;
+                                               bSkip = !bSkip;
+                                       } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
+                                               // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
+                                               if (tag_sof) {
+                                                       // Ignore bits that are transmitted during SOF
+                                                       tag_sof--;
+                                               } else {
+                                                       // bit is same as last bit
+                                                       rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
+                                                       rxlen++;
+                                               }
+                                       } else {
+                                               // Ignore wierd value, is to small to mean anything
+                                       }
+                               }
+                       }
+               }
+               
+               // Check if frame was captured
+               if(rxlen > 0) {
+                       frame_count++;
+                       if (!LogTraceHitag(rx,rxlen,response,0,reader_frame)) {
+                               DbpString("Trace full");
+                               break;
+                       }
+
+                       // Check if we recognize a valid authentication attempt
+                       if (nbytes(rxlen) == 8) {
+                               // Store the authentication attempt
+                               if (auth_table_len < (AUTH_TABLE_LENGTH-8)) {
+                                       memcpy(auth_table+auth_table_len,rx,8);
+                                       auth_table_len += 8;
+                               }
+                       }
+                       
+                       // Reset the received frame and response timing info
+                       memset(rx,0x00,sizeof(rx));
+                       response = 0;
+                       reader_frame = false;
+                       lastbit = 1;
+                       bSkip = true;
+                       tag_sof = 4;
+                       overflow = 0;
+                       
+                       LED_B_OFF();
+                       LED_C_OFF();
+               } else {
+                       // Save the timer overflow, will be 0 when frame was received
+                       overflow += (AT91C_BASE_TC1->TC_CV/T0);
+               }
+               // Reset the frame length
+               rxlen = 0;
+               // Reset the timer to restart while-loop that receives frames
+               AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
+       }
+    LED_A_ON();
+       LED_B_OFF();
+       LED_C_OFF();
+       LED_D_OFF();
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+    AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+    LED_A_OFF();
+       set_tracing(TRUE);
+//     Dbprintf("frame received: %d",frame_count);
+//     Dbprintf("Authentication Attempts: %d",(auth_table_len/8));
+//     DbpString("All done");
+}
+
+void SimulateHitagTag(bool tag_mem_supplied, byte_t* data) {
+       int frame_count;
+       int response;
+       int overflow;
+       byte_t rx[HITAG_FRAME_LEN];
+       size_t rxlen=0;
+       byte_t tx[HITAG_FRAME_LEN];
+       size_t txlen=0;
+       bool bQuitTraceFull = false;
+       bQuiet = false;
+       
+       FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+
+       // free eventually allocated BigBuf memory
+       BigBuf_free(); BigBuf_Clear_ext(false);
+
+       // Clean up trace and prepare it for storing frames
+       clear_trace();
+       set_tracing(TRUE);
+       
+       auth_table_len = 0;
+       auth_table_pos = 0;
+    byte_t* auth_table;
+
+    auth_table = (byte_t *)BigBuf_malloc(AUTH_TABLE_LENGTH);
+       memset(auth_table, 0x00, AUTH_TABLE_LENGTH);
+
+       DbpString("Starting Hitag2 simulation");
+       LED_D_ON();
+       hitag2_init();
+       
+       if (tag_mem_supplied) {
+               DbpString("Loading hitag2 memory...");
+               memcpy((byte_t*)tag.sectors,data,48);
+       }
+
+       uint32_t block = 0;
+       for (size_t i=0; i<12; i++) {
+               for (size_t j=0; j<4; j++) {
+                       block <<= 8;
+                       block |= tag.sectors[i][j];
+               }
+               Dbprintf("| %d | %08x |",i,block);
+       }
+       
+       // Set up simulator mode, frequency divisor which will drive the FPGA
+       // and analog mux selection.
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD);
+       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+       SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+       RELAY_OFF();
+
+       // Configure output pin that is connected to the FPGA (for modulating)
+       AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+       AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
+
+       // Disable modulation at default, which means release resistance
+       LOW(GPIO_SSC_DOUT);
+       
+       // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
+       AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
+       
+       // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames
+       AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
+       AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
+       
+    // Disable timer during configuration      
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+
+       // Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
+       // external trigger rising edge, load RA on rising edge of TIOA.
+       AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_RISING | AT91C_TC_ABETRG | AT91C_TC_LDRA_RISING;
+       
+       // Reset the received frame, frame count and timing info
+       memset(rx,0x00,sizeof(rx));
+       frame_count = 0;
+       response = 0;
+       overflow = 0;
+
+       // Enable and reset counter
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       
+       while(!BUTTON_PRESS() && !usb_poll_validate_length()) {
+               // Watchdog hit
+               WDT_HIT();
+               
+               // Receive frame, watch for at most T0*EOF periods
+               while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) {
+                       // Check if rising edge in modulation is detected
+                       if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
+                               // Retrieve the new timing values 
+                               int ra = (AT91C_BASE_TC1->TC_RA/T0) + overflow;
+                               overflow = 0;
+
+                               // Reset timer every frame, we have to capture the last edge for timing
+                               AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+                               
+                               LED_B_ON();
+                               
+                               // Capture reader frame
+                               if(ra >= HITAG_T_STOP) {
+                                       if (rxlen != 0) {
+                                               //DbpString("wierd0?");
+                                       }
+                                       // Capture the T0 periods that have passed since last communication or field drop (reset)
+                                       response = (ra - HITAG_T_LOW);
+                               } else if(ra >= HITAG_T_1_MIN ) {
+                                       // '1' bit 
+                                       rx[rxlen / 8] |= 1 << (7-(rxlen%8));
+                                       rxlen++;
+                               } else if(ra >= HITAG_T_0_MIN) {
+                                       // '0' bit 
+                                       rx[rxlen / 8] |= 0 << (7-(rxlen%8));
+                                       rxlen++;
+                               } else {
+                                       // Ignore wierd value, is to small to mean anything
+                               }
+                       }
+               }
+               
+               // Check if frame was captured
+               if(rxlen > 4) {
+                       frame_count++;
+                       if (!bQuiet) {
+                               if (!LogTraceHitag(rx,rxlen,response,0,true)) {
+                                       DbpString("Trace full");
+                                       if (bQuitTraceFull) {
+                                               break;
+                                       } else {
+                                               bQuiet = true;
+                                       }
+                               }
+                       }
+                       
+                       // Disable timer 1 with external trigger to avoid triggers during our own modulation
+                       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+
+                       // Process the incoming frame (rx) and prepare the outgoing frame (tx)
+                       hitag2_handle_reader_command(rx,rxlen,tx,&txlen);
+                       
+                       // Wait for HITAG_T_WAIT_1 carrier periods after the last reader bit,
+                       // not that since the clock counts since the rising edge, but T_Wait1 is
+                       // with respect to the falling edge, we need to wait actually (T_Wait1 - T_Low)
+                       // periods. The gap time T_Low varies (4..10). All timer values are in 
+                       // terms of T0 units
+                       while(AT91C_BASE_TC0->TC_CV < T0*(HITAG_T_WAIT_1-HITAG_T_LOW));
+
+                       // Send and store the tag answer (if there is any)
+                       if (txlen) {
+                               // Transmit the tag frame
+                               hitag_send_frame(tx,txlen);
+                               // Store the frame in the trace
+                               if (!bQuiet) {
+                                       if (!LogTraceHitag(tx,txlen,0,0,false)) {
+                                               DbpString("Trace full");
+                                               if (bQuitTraceFull) {
+                                                       break;
+                                               } else {
+                                                       bQuiet = true;
+                                               }
+                                       }
+                               }
+                       }
+                       
+                       // Reset the received frame and response timing info
+                       memset(rx,0x00,sizeof(rx));
+                       response = 0;
+                       
+                       // Enable and reset external trigger in timer for capturing future frames
+                       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+                       LED_B_OFF();
+               }
+               // Reset the frame length
+               rxlen = 0;
+               // Save the timer overflow, will be 0 when frame was received
+               overflow += (AT91C_BASE_TC1->TC_CV/T0);
+               // Reset the timer to restart while-loop that receives frames
+               AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
+       }
+       LED_B_OFF();
+       LED_D_OFF();
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+       
+       DbpString("Sim Stopped");
+       set_tracing(TRUE);
+}
+
+void ReaderHitag(hitag_function htf, hitag_data* htd) {
+       int frame_count;
+       int response;
+       byte_t rx[HITAG_FRAME_LEN];
+       size_t rxlen=0;
+       byte_t txbuf[HITAG_FRAME_LEN];
+       byte_t* tx = txbuf;
+       size_t txlen=0;
+       int lastbit;
+       bool bSkip;
+       int reset_sof; 
+       int tag_sof;
+       int t_wait = HITAG_T_WAIT_MAX;
+       bool bStop;
+       bool bQuitTraceFull = false;
+  
+       FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+       // Reset the return status
+       bSuccessful = false;
+  
+       // Clean up trace and prepare it for storing frames
+       clear_trace();
+       set_tracing(TRUE);
+       
+       //DbpString("Starting Hitag reader family");
+
+       // Check configuration
+       switch(htf) {
+               case RHT2F_PASSWORD: {
+                       Dbprintf("List identifier in password mode");
+                       memcpy(password,htd->pwd.password,4);
+               blocknr = 0;
+                       bQuitTraceFull = false;
+                       bQuiet = false;
+                       bPwd = false;
+               } break;
+      
+               case RHT2F_AUTHENTICATE: {
+                       DbpString("Authenticating using nr,ar pair:");
+                       memcpy(NrAr,htd->auth.NrAr,8);
+                       Dbhexdump(8,NrAr,false);
+                       bQuiet = false;
+                       bCrypto = false;
+                       bAuthenticating = false;
+                       bQuitTraceFull = true;
+               } break;
+      
+               case RHT2F_CRYPTO: {
+                       DbpString("Authenticating using key:");
+                       memcpy(key,htd->crypto.key,6);    //HACK; 4 or 6??  I read both in the code.
+                       Dbhexdump(6,key,false);
+                       blocknr = 0;
+                       bQuiet = false;
+                       bCrypto = false;
+                       bAuthenticating = false;
+                       bQuitTraceFull = true;
+               } break;
+
+               case RHT2F_TEST_AUTH_ATTEMPTS: {
+                       Dbprintf("Testing %d authentication attempts",(auth_table_len/8));
+                       auth_table_pos = 0;
+                       memcpy(NrAr, auth_table, 8);
+                       bQuitTraceFull = false;
+                       bQuiet = false;
+                       bCrypto = false;
+               } break;
+               case RHT2F_UID_ONLY: {
+                       blocknr = 0;
+                       bQuiet = false;
+                       bCrypto = false;
+                       bAuthenticating = false;
+                       bQuitTraceFull = true;
+               } break;
+               default: {
+                       Dbprintf("Error, unknown function: %d",htf);
+                       set_tracing(FALSE);
+                       return;
+               } break;
+       }
+       
+       LED_D_ON();
+       hitag2_init();
+       
+       // Configure output and enable pin that is connected to the FPGA (for modulating)
+       AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+       AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
+       
+       // Set fpga in edge detect with reader field, we can modulate as reader now
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD);
+
+       // Set Frequency divisor which will drive the FPGA and analog mux selection
+       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+       SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+       RELAY_OFF();
+
+       // Disable modulation at default, which means enable the field
+       LOW(GPIO_SSC_DOUT);
+
+       // Give it a bit of time for the resonant antenna to settle.
+       SpinDelay(30);
+       
+       // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
+       AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
+
+       // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the tag frames
+       AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
+       AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
+       
+    // Disable timer during configuration      
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+       
+       // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
+       // external trigger rising edge, load RA on falling edge of TIOA.
+       AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING;
+       
+       // Enable and reset counters
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+
+       // Reset the received frame, frame count and timing info
+       frame_count = 0;
+       response = 0;
+       lastbit = 1;
+       bStop = false;
+
+       // Tag specific configuration settings (sof, timings, etc.)
+       if (htf < 10){
+               // hitagS settings
+               reset_sof = 1;
+               t_wait = 200;
+    //DbpString("Configured for hitagS reader");
+       } else if (htf < 20) {
+               // hitag1 settings
+               reset_sof = 1;
+               t_wait = 200;
+    //DbpString("Configured for hitag1 reader");
+       } else if (htf < 30) {
+               // hitag2 settings
+               reset_sof = 4;
+               t_wait = HITAG_T_WAIT_2;
+    //DbpString("Configured for hitag2 reader");
+       } else {
+               Dbprintf("Error, unknown hitag reader type: %d",htf);
+               set_tracing(FALSE);     
+               return;
+       }
+       uint8_t attempt_count=0;
+       while(!bStop && !BUTTON_PRESS()) {
+               // Watchdog hit
+               WDT_HIT();
+               
+               // Check if frame was captured and store it
+               if(rxlen > 0) {
+                       frame_count++;
+                       if (!bQuiet) {
+                               if (!LogTraceHitag(rx,rxlen,response,0,false)) {
+                                       DbpString("Trace full");
+                                       if (bQuitTraceFull) {
+                                               break;
+                                       } else {
+                                               bQuiet = true;
+                                       }
+                               }
+                       }
+               }
+               
+               // By default reset the transmission buffer
+               tx = txbuf;
+               switch(htf) {
+                       case RHT2F_PASSWORD: {
+                               bStop = !hitag2_password(rx,rxlen,tx,&txlen);
+                       } break;
+                       case RHT2F_AUTHENTICATE: {
+                               bStop = !hitag2_authenticate(rx,rxlen,tx,&txlen);
+                       } break;
+                       case RHT2F_CRYPTO: {
+                               bStop = !hitag2_crypto(rx,rxlen,tx,&txlen);
+                       } break;
+                       case RHT2F_TEST_AUTH_ATTEMPTS: {
+                               bStop = !hitag2_test_auth_attempts(rx,rxlen,tx,&txlen);
+                       } break;
+                       case RHT2F_UID_ONLY: {
+                               bStop = !hitag2_read_uid(rx, rxlen, tx, &txlen);
+                               attempt_count++; //attempt 3 times to get uid then quit
+                               if (!bStop && attempt_count == 3) bStop = true;
+                       } break;
+                       default: {
+                               Dbprintf("Error, unknown function: %d",htf);
+                               set_tracing(FALSE);
+                               return;
+                       } break;
+               }
+               
+               // Send and store the reader command
+               // Disable timer 1 with external trigger to avoid triggers during our own modulation
+               AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+                       
+               // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting,
+               // Since the clock counts since the last falling edge, a 'one' means that the
+               // falling edge occured halfway the period. with respect to this falling edge,
+               // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'.
+               // All timer values are in terms of T0 units
+               while(AT91C_BASE_TC0->TC_CV < T0*(t_wait+(HITAG_T_TAG_HALF_PERIOD*lastbit)));
+               
+               // Transmit the reader frame
+               hitag_reader_send_frame(tx,txlen);
+
+               // Enable and reset external trigger in timer for capturing future frames
+               AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+
+               // Add transmitted frame to total count
+               if(txlen > 0) {
+                       frame_count++;
+                       if (!bQuiet) {
+                               // Store the frame in the trace
+                               if (!LogTraceHitag(tx,txlen,HITAG_T_WAIT_2,0,true)) {
+                                       if (bQuitTraceFull) {
+                                               break;
+                                       } else {
+                                               bQuiet = true;
+                                       }
+                               }
+                       }
+               }
+                               
+               // Reset values for receiving frames
+               memset(rx,0x00,sizeof(rx));
+               rxlen = 0;
+               lastbit = 1;
+               bSkip = true;
+               tag_sof = reset_sof;
+               response = 0;
+                       //Dbprintf("DEBUG: Waiting to receive frame");
+               uint32_t errorCount = 0;
+               
+               // Receive frame, watch for at most T0*EOF periods
+               while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_WAIT_MAX) {
+                       // Check if falling edge in tag modulation is detected
+                       if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
+                               // Retrieve the new timing values 
+                               int ra = (AT91C_BASE_TC1->TC_RA/T0);
+                               
+                               // Reset timer every frame, we have to capture the last edge for timing
+                               AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
+                               
+                               LED_B_ON();
+                               
+                               // Capture tag frame (manchester decoding using only falling edges)
+                               if(ra >= HITAG_T_EOF) {
+                                       if (rxlen != 0) {
+                                               //DbpString("wierd1?");
+                                       }
+                                       // Capture the T0 periods that have passed since last communication or field drop (reset)
+                                       // We always recieve a 'one' first, which has the falling edge after a half period |-_|
+                                       response = ra-HITAG_T_TAG_HALF_PERIOD;
+                               } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
+                                       // Manchester coding example |-_|_-|-_| (101)
+                                       rx[rxlen / 8] |= 0 << (7-(rxlen%8));
+                                       rxlen++;
+                                       rx[rxlen / 8] |= 1 << (7-(rxlen%8));
+                                       rxlen++;
+                               } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
+                                       // Manchester coding example |_-|...|_-|-_| (0...01)
+                                       rx[rxlen / 8] |= 0 << (7-(rxlen%8));
+                                       rxlen++;
+                                       // We have to skip this half period at start and add the 'one' the second time 
+                                       if (!bSkip) {
+                                               rx[rxlen / 8] |= 1 << (7-(rxlen%8));
+                                               rxlen++;
+                                       }
+                                       lastbit = !lastbit;
+                                       bSkip = !bSkip;
+                               } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
+                                       // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
+                                       if (tag_sof) {
+                                               // Ignore bits that are transmitted during SOF
+                                               tag_sof--;
+                                       } else {
+                                               // bit is same as last bit
+                                               rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
+                                               rxlen++;
+                                       }
+                               } else {
+                                               //Dbprintf("DEBUG: Wierd2");
+                                               errorCount++;
+                                       // Ignore wierd value, is to small to mean anything
+                               }
+                       }
+                       //if we saw over 100 wierd values break it probably isn't hitag...
+                       if (errorCount >100) break;
+                       // We can break this loop if we received the last bit from a frame
+                       if (AT91C_BASE_TC1->TC_CV > T0*HITAG_T_EOF) {
+                               if (rxlen>0) break;
+                       }
+               }
+       }
+       LED_B_OFF();
+       LED_D_OFF();
+       AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+       AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+//     Dbprintf("DONE: frame received: %d",frame_count);
+       cmd_send(CMD_ACK,bSuccessful,0,0,(byte_t*)tag.sectors,48);
+       set_tracing(FALSE);
+}
\ No newline at end of file
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