]> git.zerfleddert.de Git - proxmark3-svn/blobdiff - armsrc/iso14443a.c
Updated proxmark research with Holiman's loclass framework
[proxmark3-svn] / armsrc / iso14443a.c
index ba4e6cf4d6128a777d457b1a4c71ba0940e770ab..b105e792d3af7f5d4ca7e672a378912764af7b1e 100644 (file)
 
 static uint32_t iso14a_timeout;
 uint8_t *trace = (uint8_t *) BigBuf+TRACE_OFFSET;
-int traceLen = 0;
 int rsamples = 0;
+int traceLen = 0;
 int tracing = TRUE;
 uint8_t trigger = 0;
 // the block number for the ISO14443-4 PCB
 static uint8_t iso14_pcb_blocknum = 0;
 
+//
+// ISO14443 timing:
+//
+// minimum time between the start bits of consecutive transfers from reader to tag: 7000 carrier (13.56Mhz) cycles
+#define REQUEST_GUARD_TIME (7000/16 + 1)
+// minimum time between last modulation of tag and next start bit from reader to tag: 1172 carrier cycles 
+#define FRAME_DELAY_TIME_PICC_TO_PCD (1172/16 + 1) 
+// bool LastCommandWasRequest = FALSE;
+
+//
+// Total delays including SSC-Transfers between ARM and FPGA. These are in carrier clock cycles (1/13,56MHz)
+//
+// When the PM acts as reader and is receiving, it takes 
+// 3 ticks for the A/D conversion
+// 10 ticks ( 16 on average) delay in the modulation detector.
+// 6 ticks until the SSC samples the first data
+// 7*16 ticks to complete the transfer from FPGA to ARM
+// 8 ticks to the next ssp_clk rising edge
+// 4*16 ticks until we measure the time
+// - 8*16 ticks because we measure the time of the previous transfer 
+#define DELAY_AIR2ARM_AS_READER (3 + 10 + 6 + 7*16 + 8 + 4*16 - 8*16) 
+
+// When the PM acts as a reader and is sending, it takes
+// 4*16 ticks until we can write data to the sending hold register
+// 8*16 ticks until the SHR is transferred to the Sending Shift Register
+// 8 ticks until the first transfer starts
+// 8 ticks later the FPGA samples the data
+// 1 tick to assign mod_sig_coil
+#define DELAY_ARM2AIR_AS_READER (4*16 + 8*16 + 8 + 8 + 1)
+
+// When the PM acts as tag and is receiving it takes
+// 12 ticks delay in the RF part,
+// 3 ticks for the A/D conversion,
+// 8 ticks on average until the start of the SSC transfer,
+// 8 ticks until the SSC samples the first data
+// 7*16 ticks to complete the transfer from FPGA to ARM
+// 8 ticks until the next ssp_clk rising edge
+// 3*16 ticks until we measure the time 
+// - 8*16 ticks because we measure the time of the previous transfer 
+#define DELAY_AIR2ARM_AS_TAG (12 + 3 + 8 + 8 + 7*16 + 8 + 3*16 - 8*16)
+// The FPGA will report its internal sending delay in
+uint16_t FpgaSendQueueDelay;
+// the 5 first bits are the number of bits buffered in mod_sig_buf
+// the last three bits are the remaining ticks/2 after the mod_sig_buf shift
+#define DELAY_FPGA_QUEUE (FpgaSendQueueDelay<<1)
+
+// When the PM acts as tag and is sending, it takes
+// 5*16 ticks until we can write data to the sending hold register
+// 8*16 ticks until the SHR is transferred to the Sending Shift Register
+// 8 ticks until the first transfer starts
+// 8 ticks later the FPGA samples the data
+// + a varying number of ticks in the FPGA Delay Queue (mod_sig_buf)
+// + 1 tick to assign mod_sig_coil
+#define DELAY_ARM2AIR_AS_TAG (5*16 + 8*16 + 8 + 8 + DELAY_FPGA_QUEUE + 1)
+
+// When the PM acts as sniffer and is receiving tag data, it takes
+// 3 ticks A/D conversion
+// 16 ticks delay in the modulation detector (on average).
+// + 16 ticks until it's result is sampled.
+// + the delays in transferring data - which is the same for
+// sniffing reader and tag data and therefore not relevant
+#define DELAY_TAG_AIR2ARM_AS_SNIFFER (3 + 16 + 16) 
+// When the PM acts as sniffer and is receiving tag data, it takes
+// 12 ticks delay in analogue RF receiver
+// 3 ticks A/D conversion
+// 8 ticks on average until we sample the data.
+// + the delays in transferring data - which is the same for
+// sniffing reader and tag data and therefore not relevant
+#define DELAY_READER_AIR2ARM_AS_SNIFFER (12 + 3 + 8) 
+
+//variables used for timing purposes:
+//these are in ssp_clk cycles:
+uint32_t NextTransferTime;
+uint32_t LastTimeProxToAirStart;
+uint32_t LastProxToAirDuration;
+
+
+
 // CARD TO READER - manchester
 // Sequence D: 11110000 modulation with subcarrier during first half
 // Sequence E: 00001111 modulation with subcarrier during second half
@@ -70,7 +150,7 @@ void iso14a_set_trigger(bool enable) {
 }
 
 void iso14a_clear_trace() {
-  memset(trace, 0x44, TRACE_SIZE);
+       memset(trace, 0x44, TRACE_SIZE);
        traceLen = 0;
 }
 
@@ -110,274 +190,201 @@ void AppendCrc14443a(uint8_t* data, int len)
 }
 
 // The function LogTrace() is also used by the iClass implementation in iClass.c
-int RAMFUNC LogTrace(const uint8_t * btBytes, int iLen, int iSamples, uint32_t dwParity, int bReader)
+bool RAMFUNC LogTrace(const uint8_t * btBytes, uint8_t iLen, uint32_t timestamp, uint32_t dwParity, bool bReader)
 {
-  // Return when trace is full
-  if (traceLen >= TRACE_SIZE) return FALSE;
-
-  // Trace the random, i'm curious
-  rsamples += iSamples;
-  trace[traceLen++] = ((rsamples >> 0) & 0xff);
-  trace[traceLen++] = ((rsamples >> 8) & 0xff);
-  trace[traceLen++] = ((rsamples >> 16) & 0xff);
-  trace[traceLen++] = ((rsamples >> 24) & 0xff);
-  if (!bReader) {
-    trace[traceLen - 1] |= 0x80;
-  }
-  trace[traceLen++] = ((dwParity >> 0) & 0xff);
-  trace[traceLen++] = ((dwParity >> 8) & 0xff);
-  trace[traceLen++] = ((dwParity >> 16) & 0xff);
-  trace[traceLen++] = ((dwParity >> 24) & 0xff);
-  trace[traceLen++] = iLen;
-  memcpy(trace + traceLen, btBytes, iLen);
-  traceLen += iLen;
-  return TRUE;
+       // Return when trace is full
+       if (traceLen + sizeof(timestamp) + sizeof(dwParity) + iLen >= TRACE_SIZE) {
+               tracing = FALSE;        // don't trace any more
+               return FALSE;
+       }
+       
+       // Trace the random, i'm curious
+       trace[traceLen++] = ((timestamp >> 0) & 0xff);
+       trace[traceLen++] = ((timestamp >> 8) & 0xff);
+       trace[traceLen++] = ((timestamp >> 16) & 0xff);
+       trace[traceLen++] = ((timestamp >> 24) & 0xff);
+       if (!bReader) {
+               trace[traceLen - 1] |= 0x80;
+       }
+       trace[traceLen++] = ((dwParity >> 0) & 0xff);
+       trace[traceLen++] = ((dwParity >> 8) & 0xff);
+       trace[traceLen++] = ((dwParity >> 16) & 0xff);
+       trace[traceLen++] = ((dwParity >> 24) & 0xff);
+       trace[traceLen++] = iLen;
+       if (btBytes != NULL && iLen != 0) {
+               memcpy(trace + traceLen, btBytes, iLen);
+       }
+       traceLen += iLen;
+       return TRUE;
 }
 
-//-----------------------------------------------------------------------------
-// The software UART that receives commands from the reader, and its state
-// variables.
+//=============================================================================
+// ISO 14443 Type A - Miller decoder
+//=============================================================================
+// Basics:
+// This decoder is used when the PM3 acts as a tag.
+// The reader will generate "pauses" by temporarily switching of the field. 
+// At the PM3 antenna we will therefore measure a modulated antenna voltage. 
+// The FPGA does a comparison with a threshold and would deliver e.g.:
+// ........  1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1  .......
+// The Miller decoder needs to identify the following sequences:
+// 2 (or 3) ticks pause followed by 6 (or 5) ticks unmodulated:        pause at beginning - Sequence Z ("start of communication" or a "0")
+// 8 ticks without a modulation:                                                                       no pause - Sequence Y (a "0" or "end of communication" or "no information")
+// 4 ticks unmodulated followed by 2 (or 3) ticks pause:                       pause in second half - Sequence X (a "1")
+// Note 1: the bitstream may start at any time. We therefore need to sync.
+// Note 2: the interpretation of Sequence Y and Z depends on the preceding sequence.
 //-----------------------------------------------------------------------------
 static tUart Uart;
 
-static RAMFUNC int MillerDecoding(int bit)
+// Lookup-Table to decide if 4 raw bits are a modulation.
+// We accept two or three consecutive "0" in any position with the rest "1"
+const bool Mod_Miller_LUT[] = {
+       TRUE,  TRUE,  FALSE, TRUE,  FALSE, FALSE, FALSE, FALSE,
+       TRUE,  TRUE,  FALSE, FALSE, TRUE,  FALSE, FALSE, FALSE
+};
+#define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x00F0) >> 4])
+#define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x000F)])
+
+void UartReset()
 {
-       //int error = 0;
-       int bitright;
+       Uart.state = STATE_UNSYNCD;
+       Uart.bitCount = 0;
+       Uart.len = 0;                                           // number of decoded data bytes
+       Uart.shiftReg = 0;                                      // shiftreg to hold decoded data bits
+       Uart.parityBits = 0;                            // 
+       Uart.twoBits = 0x0000;                          // buffer for 2 Bits
+       Uart.highCnt = 0;
+       Uart.startTime = 0;
+       Uart.endTime = 0;
+}
 
-       if(!Uart.bitBuffer) {
-               Uart.bitBuffer = bit ^ 0xFF0;
-               return FALSE;
-       }
-       else {
-               Uart.bitBuffer <<= 4;
-               Uart.bitBuffer ^= bit;
+/* inline RAMFUNC Modulation_t MillerModulation(uint8_t b)
+{
+       // switch (b & 0x88) {
+               // case 0x00:   return MILLER_MOD_BOTH_HALVES;
+               // case 0x08:   return MILLER_MOD_FIRST_HALF;
+               // case 0x80:   return MILLER_MOD_SECOND_HALF;
+               // case 0x88:   return MILLER_MOD_NOMOD;
+       // }
+       // test the second cycle for a pause. For whatever reason the startbit tends to appear earlier than the rest.
+       switch (b & 0x44) {
+               case 0x00:      return MOD_BOTH_HALVES;
+               case 0x04:      return MOD_FIRST_HALF;
+               case 0x40:      return MOD_SECOND_HALF;
+               default:        return MOD_NOMOD;
        }
+}
+ */
+// use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
+static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
+{
 
-       int EOC = FALSE;
-
-       if(Uart.state != STATE_UNSYNCD) {
-               Uart.posCnt++;
-
-               if((Uart.bitBuffer & Uart.syncBit) ^ Uart.syncBit) {
-                       bit = 0x00;
-               }
-               else {
-                       bit = 0x01;
-               }
-               if(((Uart.bitBuffer << 1) & Uart.syncBit) ^ Uart.syncBit) {
-                       bitright = 0x00;
-               }
-               else {
-                       bitright = 0x01;
-               }
-               if(bit != bitright) { bit = bitright; }
-
-               if(Uart.posCnt == 1) {
-                       // measurement first half bitperiod
-                       if(!bit) {
-                               Uart.drop = DROP_FIRST_HALF;
-                       }
-               }
-               else {
-                       // measurement second half bitperiod
-                       if(!bit & (Uart.drop == DROP_NONE)) {
-                               Uart.drop = DROP_SECOND_HALF;
+       Uart.twoBits = (Uart.twoBits << 8) | bit;
+       
+       if (Uart.state == STATE_UNSYNCD) {                                                                                              // not yet synced
+               if (Uart.highCnt < 7) {                                                                                                 // wait for a stable unmodulated signal
+                       if (Uart.twoBits == 0xffff) {
+                               Uart.highCnt++;
+                       } else {
+                               Uart.highCnt = 0;
                        }
-                       else if(!bit) {
-                               // measured a drop in first and second half
-                               // which should not be possible
-                               Uart.state = STATE_ERROR_WAIT;
-                               //error = 0x01;
+               } else {        
+                       Uart.syncBit = 0xFFFF; // not set
+                       // look for 00xx1111 (the start bit)
+                       if              ((Uart.twoBits & 0x6780) == 0x0780) Uart.syncBit = 7; 
+                       else if ((Uart.twoBits & 0x33C0) == 0x03C0) Uart.syncBit = 6;
+                       else if ((Uart.twoBits & 0x19E0) == 0x01E0) Uart.syncBit = 5;
+                       else if ((Uart.twoBits & 0x0CF0) == 0x00F0) Uart.syncBit = 4;
+                       else if ((Uart.twoBits & 0x0678) == 0x0078) Uart.syncBit = 3;
+                       else if ((Uart.twoBits & 0x033C) == 0x003C) Uart.syncBit = 2;
+                       else if ((Uart.twoBits & 0x019E) == 0x001E) Uart.syncBit = 1;
+                       else if ((Uart.twoBits & 0x00CF) == 0x000F) Uart.syncBit = 0;
+                       if (Uart.syncBit != 0xFFFF) {
+                               Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
+                               Uart.startTime -= Uart.syncBit;
+                               Uart.endTime = Uart.startTime;
+                               Uart.state = STATE_START_OF_COMMUNICATION;
                        }
+               }
 
-                       Uart.posCnt = 0;
-
-                       switch(Uart.state) {
-                               case STATE_START_OF_COMMUNICATION:
-                                       Uart.shiftReg = 0;
-                                       if(Uart.drop == DROP_SECOND_HALF) {
-                                               // error, should not happen in SOC
-                                               Uart.state = STATE_ERROR_WAIT;
-                                               //error = 0x02;
-                                       }
-                                       else {
-                                               // correct SOC
-                                               Uart.state = STATE_MILLER_Z;
-                                       }
-                                       break;
-
-                               case STATE_MILLER_Z:
-                                       Uart.bitCnt++;
-                                       Uart.shiftReg >>= 1;
-                                       if(Uart.drop == DROP_NONE) {
-                                               // logic '0' followed by sequence Y
-                                               // end of communication
-                                               Uart.state = STATE_UNSYNCD;
-                                               EOC = TRUE;
-                                       }
-                                       // if(Uart.drop == DROP_FIRST_HALF) {
-                                       //      Uart.state = STATE_MILLER_Z; stay the same
-                                       //      we see a logic '0' }
-                                       if(Uart.drop == DROP_SECOND_HALF) {
-                                               // we see a logic '1'
-                                               Uart.shiftReg |= 0x100;
-                                               Uart.state = STATE_MILLER_X;
-                                       }
-                                       break;
-
-                               case STATE_MILLER_X:
-                                       Uart.shiftReg >>= 1;
-                                       if(Uart.drop == DROP_NONE) {
-                                               // sequence Y, we see a '0'
-                                               Uart.state = STATE_MILLER_Y;
-                                               Uart.bitCnt++;
-                                       }
-                                       if(Uart.drop == DROP_FIRST_HALF) {
-                                               // Would be STATE_MILLER_Z
-                                               // but Z does not follow X, so error
-                                               Uart.state = STATE_ERROR_WAIT;
-                                               //error = 0x03;
-                                       }
-                                       if(Uart.drop == DROP_SECOND_HALF) {
-                                               // We see a '1' and stay in state X
-                                               Uart.shiftReg |= 0x100;
-                                               Uart.bitCnt++;
-                                       }
-                                       break;
-
-                               case STATE_MILLER_Y:
-                                       Uart.bitCnt++;
-                                       Uart.shiftReg >>= 1;
-                                       if(Uart.drop == DROP_NONE) {
-                                               // logic '0' followed by sequence Y
-                                               // end of communication
-                                               Uart.state = STATE_UNSYNCD;
-                                               EOC = TRUE;
-                                       }
-                                       if(Uart.drop == DROP_FIRST_HALF) {
-                                               // we see a '0'
-                                               Uart.state = STATE_MILLER_Z;
-                                       }
-                                       if(Uart.drop == DROP_SECOND_HALF) {
-                                               // We see a '1' and go to state X
-                                               Uart.shiftReg |= 0x100;
-                                               Uart.state = STATE_MILLER_X;
-                                       }
-                                       break;
+       } else {
 
-                               case STATE_ERROR_WAIT:
-                                       // That went wrong. Now wait for at least two bit periods
-                                       // and try to sync again
-                                       if(Uart.drop == DROP_NONE) {
-                                               Uart.highCnt = 6;
-                                               Uart.state = STATE_UNSYNCD;
+               if (IsMillerModulationNibble1(Uart.twoBits >> Uart.syncBit)) {                  
+                       if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) {          // Modulation in both halves - error
+                               UartReset();
+                               Uart.highCnt = 6;
+                       } else {                                                                                                                        // Modulation in first half = Sequence Z = logic "0"
+                               if (Uart.state == STATE_MILLER_X) {                                                             // error - must not follow after X
+                                       UartReset();
+                                       Uart.highCnt = 6;
+                               } else {
+                                       Uart.bitCount++;
+                                       Uart.shiftReg = (Uart.shiftReg >> 1);                                           // add a 0 to the shiftreg
+                                       Uart.state = STATE_MILLER_Z;
+                                       Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 6;
+                                       if(Uart.bitCount >= 9) {                                                                        // if we decoded a full byte (including parity)
+                                               Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
+                                               Uart.parityBits <<= 1;                                                                  // make room for the parity bit
+                                               Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01);               // store parity bit
+                                               Uart.bitCount = 0;
+                                               Uart.shiftReg = 0;
                                        }
-                                       break;
-
-                               default:
-                                       Uart.state = STATE_UNSYNCD;
-                                       Uart.highCnt = 0;
-                                       break;
-                       }
-
-                       Uart.drop = DROP_NONE;
-
-                       // should have received at least one whole byte...
-                       if((Uart.bitCnt == 2) && EOC && (Uart.byteCnt > 0)) {
-                               return TRUE;
+                               }
                        }
-
-                       if(Uart.bitCnt == 9) {
-                               Uart.output[Uart.byteCnt] = (Uart.shiftReg & 0xff);
-                               Uart.byteCnt++;
-
-                               Uart.parityBits <<= 1;
-                               Uart.parityBits ^= ((Uart.shiftReg >> 8) & 0x01);
-
-                               if(EOC) {
-                                       // when End of Communication received and
-                                       // all data bits processed..
+               } else {
+                       if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) {          // Modulation second half = Sequence X = logic "1"
+                               Uart.bitCount++;
+                               Uart.shiftReg = (Uart.shiftReg >> 1) | 0x100;                                   // add a 1 to the shiftreg
+                               Uart.state = STATE_MILLER_X;
+                               Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 2;
+                               if(Uart.bitCount >= 9) {                                                                                // if we decoded a full byte (including parity)
+                                       Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
+                                       Uart.parityBits <<= 1;                                                                          // make room for the new parity bit
+                                       Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01);                       // store parity bit
+                                       Uart.bitCount = 0;
+                                       Uart.shiftReg = 0;
+                               }
+                       } else {                                                                                                                        // no modulation in both halves - Sequence Y
+                               if (Uart.state == STATE_MILLER_Z || Uart.state == STATE_MILLER_Y) {     // Y after logic "0" - End of Communication
+                                       Uart.state = STATE_UNSYNCD;
+                                       if(Uart.len == 0 && Uart.bitCount > 0) {                                                                                // if we decoded some bits
+                                               Uart.shiftReg >>= (9 - Uart.bitCount);                                  // add them to the output
+                                               Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
+                                               Uart.parityBits <<= 1;                                                                  // no parity bit - add "0"
+                                               Uart.bitCount--;                                                                                // last "0" was part of the EOC sequence
+                                       }
                                        return TRUE;
                                }
-                               Uart.bitCnt = 0;
-                       }
-
-                       /*if(error) {
-                               Uart.output[Uart.byteCnt] = 0xAA;
-                               Uart.byteCnt++;
-                               Uart.output[Uart.byteCnt] = error & 0xFF;
-                               Uart.byteCnt++;
-                               Uart.output[Uart.byteCnt] = 0xAA;
-                               Uart.byteCnt++;
-                               Uart.output[Uart.byteCnt] = (Uart.bitBuffer >> 8) & 0xFF;
-                               Uart.byteCnt++;
-                               Uart.output[Uart.byteCnt] = Uart.bitBuffer & 0xFF;
-                               Uart.byteCnt++;
-                               Uart.output[Uart.byteCnt] = (Uart.syncBit >> 3) & 0xFF;
-                               Uart.byteCnt++;
-                               Uart.output[Uart.byteCnt] = 0xAA;
-                               Uart.byteCnt++;
-                               return TRUE;
-                       }*/
-               }
-
-       }
-       else {
-               bit = Uart.bitBuffer & 0xf0;
-               bit >>= 4;
-               bit ^= 0x0F;
-               if(bit) {
-                       // should have been high or at least (4 * 128) / fc
-                       // according to ISO this should be at least (9 * 128 + 20) / fc
-                       if(Uart.highCnt == 8) {
-                               // we went low, so this could be start of communication
-                               // it turns out to be safer to choose a less significant
-                               // syncbit... so we check whether the neighbour also represents the drop
-                               Uart.posCnt = 1;   // apparently we are busy with our first half bit period
-                               Uart.syncBit = bit & 8;
-                               Uart.samples = 3;
-                               if(!Uart.syncBit)       { Uart.syncBit = bit & 4; Uart.samples = 2; }
-                               else if(bit & 4)        { Uart.syncBit = bit & 4; Uart.samples = 2; bit <<= 2; }
-                               if(!Uart.syncBit)       { Uart.syncBit = bit & 2; Uart.samples = 1; }
-                               else if(bit & 2)        { Uart.syncBit = bit & 2; Uart.samples = 1; bit <<= 1; }
-                               if(!Uart.syncBit)       { Uart.syncBit = bit & 1; Uart.samples = 0;
-                                       if(Uart.syncBit && (Uart.bitBuffer & 8)) {
-                                               Uart.syncBit = 8;
-
-                                               // the first half bit period is expected in next sample
-                                               Uart.posCnt = 0;
-                                               Uart.samples = 3;
+                               if (Uart.state == STATE_START_OF_COMMUNICATION) {                               // error - must not follow directly after SOC
+                                       UartReset();
+                                       Uart.highCnt = 6;
+                               } else {                                                                                                                // a logic "0"
+                                       Uart.bitCount++;
+                                       Uart.shiftReg = (Uart.shiftReg >> 1);                                           // add a 0 to the shiftreg
+                                       Uart.state = STATE_MILLER_Y;
+                                       if(Uart.bitCount >= 9) {                                                                        // if we decoded a full byte (including parity)
+                                               Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
+                                               Uart.parityBits <<= 1;                                                                  // make room for the parity bit
+                                               Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01);               // store parity bit
+                                               Uart.bitCount = 0;
+                                               Uart.shiftReg = 0;
                                        }
                                }
-                               else if(bit & 1)        { Uart.syncBit = bit & 1; Uart.samples = 0; }
-
-                               Uart.syncBit <<= 4;
-                               Uart.state = STATE_START_OF_COMMUNICATION;
-                               Uart.drop = DROP_FIRST_HALF;
-                               Uart.bitCnt = 0;
-                               Uart.byteCnt = 0;
-                               Uart.parityBits = 0;
-                               //error = 0;
-                       }
-                       else {
-                               Uart.highCnt = 0;
-                       }
-               }
-               else {
-                       if(Uart.highCnt < 8) {
-                               Uart.highCnt++;
                        }
                }
-       }
+                       
+       } 
 
-    return FALSE;
+    return FALSE;      // not finished yet, need more data
 }
 
+
+
 //=============================================================================
 // ISO 14443 Type A - Manchester decoder
 //=============================================================================
 // Basics:
+// This decoder is used when the PM3 acts as a reader.
 // The tag will modulate the reader field by asserting different loads to it. As a consequence, the voltage
 // at the reader antenna will be modulated as well. The FPGA detects the modulation for us and would deliver e.g. the following:
 // ........ 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 .......
@@ -386,161 +393,110 @@ static RAMFUNC int MillerDecoding(int bit)
 // 4 ticks unmodulated followed by 4 ticks modulated:  Sequence E = 0
 // 8 ticks unmodulated:                                                                        Sequence F = end of communication
 // 8 ticks modulated:                                                                  A collision. Save the collision position and treat as Sequence D
-// Note 1: the bitstream may start at any time (either in first or second nibble within the parameter bit). We therefore need to sync.
+// Note 1: the bitstream may start at any time. We therefore need to sync.
 // Note 2: parameter offset is used to determine the position of the parity bits (required for the anticollision command only)
 static tDemod Demod;
 
-inline RAMFUNC bool IsModulation(byte_t b)
-{
-       if (b >= 5 || b == 3)           // majority decision: 2 or more bits are set
-               return true;
-       else
-               return false;
-       
-}
+// Lookup-Table to decide if 4 raw bits are a modulation.
+// We accept three or four consecutive "1" in any position
+const bool Mod_Manchester_LUT[] = {
+       FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE,
+       FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE,  TRUE
+};
+
+#define IsManchesterModulationNibble1(b) (Mod_Manchester_LUT[(b & 0x00F0) >> 4])
+#define IsManchesterModulationNibble2(b) (Mod_Manchester_LUT[(b & 0x000F)])
 
-inline RAMFUNC bool IsModulationNibble1(byte_t b)
-{
-       return IsModulation((b & 0xE0) >> 5);
-}
 
-inline RAMFUNC bool IsModulationNibble2(byte_t b)
+void DemodReset()
 {
-       return IsModulation((b & 0x0E) >> 1);
+       Demod.state = DEMOD_UNSYNCD;
+       Demod.len = 0;                                          // number of decoded data bytes
+       Demod.shiftReg = 0;                                     // shiftreg to hold decoded data bits
+       Demod.parityBits = 0;                           // 
+       Demod.collisionPos = 0;                         // Position of collision bit
+       Demod.twoBits = 0xffff;                         // buffer for 2 Bits
+       Demod.highCnt = 0;
+       Demod.startTime = 0;
+       Demod.endTime = 0;
 }
 
-static RAMFUNC int ManchesterDecoding(int bit, uint16_t offset)
+// use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
+static RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non_real_time)
 {
+
+       Demod.twoBits = (Demod.twoBits << 8) | bit;
        
-       switch (Demod.state) {
-
-               case DEMOD_UNSYNCD:                                             // not yet synced
-                       Demod.len = 0;                                          // initialize number of decoded data bytes
-                       Demod.bitCount = offset;                        // initialize number of decoded data bits
-                       Demod.shiftReg = 0;                                     // initialize shiftreg to hold decoded data bits
-                       Demod.parityBits = 0;                           // initialize parity bits
-                       Demod.collisionPos = 0;                         // Position of collision bit
-                       
-                       if (IsModulationNibble1(bit) 
-                               && !IsModulationNibble2(bit)) {                                                         // this is the start bit
-                               Demod.samples = 8;
-                               if(trigger) LED_A_OFF();
+       if (Demod.state == DEMOD_UNSYNCD) {
+
+               if (Demod.highCnt < 2) {                                                                                        // wait for a stable unmodulated signal
+                       if (Demod.twoBits == 0x0000) {
+                               Demod.highCnt++;
+                       } else {
+                               Demod.highCnt = 0;
+                       }
+               } else {
+                       Demod.syncBit = 0xFFFF;                 // not set
+                       if              ((Demod.twoBits & 0x7700) == 0x7000) Demod.syncBit = 7; 
+                       else if ((Demod.twoBits & 0x3B80) == 0x3800) Demod.syncBit = 6;
+                       else if ((Demod.twoBits & 0x1DC0) == 0x1C00) Demod.syncBit = 5;
+                       else if ((Demod.twoBits & 0x0EE0) == 0x0E00) Demod.syncBit = 4;
+                       else if ((Demod.twoBits & 0x0770) == 0x0700) Demod.syncBit = 3;
+                       else if ((Demod.twoBits & 0x03B8) == 0x0380) Demod.syncBit = 2;
+                       else if ((Demod.twoBits & 0x01DC) == 0x01C0) Demod.syncBit = 1;
+                       else if ((Demod.twoBits & 0x00EE) == 0x00E0) Demod.syncBit = 0;
+                       if (Demod.syncBit != 0xFFFF) {
+                               Demod.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
+                               Demod.startTime -= Demod.syncBit;
+                               Demod.bitCount = offset;                        // number of decoded data bits
                                Demod.state = DEMOD_MANCHESTER_DATA;
-                       } else if (!IsModulationNibble1(bit) && IsModulationNibble2(bit)) { // this may be the first half of the start bit
-                                       Demod.samples = 4;
-                                       Demod.state = DEMOD_HALF_SYNCD;
                        }
-                       break;
+               }
 
+       } else {
 
-               case DEMOD_HALF_SYNCD:
-                       Demod.samples += 8;
-                       if (IsModulationNibble1(bit)) {                                                         // error: this was not a start bit.
-                               Demod.state = DEMOD_UNSYNCD;
-                       } else {
-                               if (IsModulationNibble2(bit)) {                                                 // modulation in first half
-                                       Demod.state = DEMOD_MOD_FIRST_HALF;
-                               } else {                                                                                                // no modulation in first half
-                                       Demod.state = DEMOD_NOMOD_FIRST_HALF;
-                               }
-                       }
-                       break;
-                       
-                       
-               case DEMOD_MOD_FIRST_HALF:
-                       Demod.samples += 8;
-                       Demod.bitCount++;
-                       if (IsModulationNibble1(bit)) {                                                         // modulation in both halfs - collision
+               if (IsManchesterModulationNibble1(Demod.twoBits >> Demod.syncBit)) {            // modulation in first half
+                       if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) {    // ... and in second half = collision
                                if (!Demod.collisionPos) {
                                        Demod.collisionPos = (Demod.len << 3) + Demod.bitCount;
                                }
                        }                                                                                                                       // modulation in first half only - Sequence D = 1
-                       Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100;                         // add a 1 to the shiftreg
-                       if(Demod.bitCount >= 9) {                                                                       // if we decoded a full byte (including parity)
-                               Demod.parityBits <<= 1;                                                                 // make room for the parity bit
+                       Demod.bitCount++;
+                       Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100;                         // in both cases, add a 1 to the shiftreg
+                       if(Demod.bitCount == 9) {                                                                       // if we decoded a full byte (including parity)
                                Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
+                               Demod.parityBits <<= 1;                                                                 // make room for the parity bit
                                Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01);     // store parity bit
                                Demod.bitCount = 0;
                                Demod.shiftReg = 0;
                        }
-                       if (IsModulationNibble2(bit)) {                                                         // modulation in first half
-                               Demod.state = DEMOD_MOD_FIRST_HALF;
-                       } else {                                                                                                        // no modulation in first half
-                               Demod.state = DEMOD_NOMOD_FIRST_HALF;
-                       }
-                       break;
-
-
-               case DEMOD_NOMOD_FIRST_HALF:
-                       if (IsModulationNibble1(bit)) {                                                         // modulation in second half only - Sequence E = 0
+                       Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1) - 4;
+               } else {                                                                                                                // no modulation in first half
+                       if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) {    // and modulation in second half = Sequence E = 0
                                Demod.bitCount++;
-                               Demod.samples += 8;
-                               Demod.shiftReg = (Demod.shiftReg >> 1);                                 // add a 0 to the shiftreg
+                               Demod.shiftReg = (Demod.shiftReg >> 1);                                 // add a 0 to the shiftreg
                                if(Demod.bitCount >= 9) {                                                               // if we decoded a full byte (including parity)
-                                       Demod.parityBits <<= 1;                                                         // make room for the new parity bit
                                        Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
+                                       Demod.parityBits <<= 1;                                                         // make room for the new parity bit
                                        Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
                                        Demod.bitCount = 0;
                                        Demod.shiftReg = 0;
                                }
+                               Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1);
                        } else {                                                                                                        // no modulation in both halves - End of communication
-                               Demod.samples += 4;
-                               if(Demod.bitCount > 0) {                                                                // if we decoded bits
-                                       Demod.shiftReg >>= (9 - Demod.bitCount);                        // add the remaining decoded bits to the output
-                                       Demod.output[Demod.len++] = Demod.shiftReg & 0xff;
-                                       // No parity bit, so just shift a 0
-                                       Demod.parityBits <<= 1;
-                               }
-                               Demod.state = DEMOD_UNSYNCD;                                                    // start from the beginning
-                               return TRUE;                                                                                    // we are finished with decoding the raw data sequence
-                       }
-                       if (IsModulationNibble2(bit)) {                                                         // modulation in first half
-                               Demod.state = DEMOD_MOD_FIRST_HALF;
-                       } else {                                                                                                        // no modulation in first half
-                               Demod.state = DEMOD_NOMOD_FIRST_HALF;
-                       }
-                       break;
-                       
-
-               case DEMOD_MANCHESTER_DATA:
-                       Demod.samples += 8;
-                       if (IsModulationNibble1(bit)) {                                                                 // modulation in first half
-                               if (IsModulationNibble2(bit) & 0x0f) {                                          // ... and in second half = collision
-                                       if (!Demod.collisionPos) {
-                                               Demod.collisionPos = (Demod.len << 3) + Demod.bitCount;
-                                       }
-                               }                                                                                                               // modulation in first half only - Sequence D = 1
-                               Demod.bitCount++;
-                               Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100;                 // in both cases, add a 1 to the shiftreg
-                               if(Demod.bitCount >= 9) {                                                               // if we decoded a full byte (including parity)
-                                       Demod.parityBits <<= 1;                                                         // make room for the parity bit
-                                       Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
-                                       Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
-                                       Demod.bitCount = 0;
-                                       Demod.shiftReg = 0;
-                               }
-                       } else {                                                                                                        // no modulation in first half
-                               if (IsModulationNibble2(bit)) {                                                 // and modulation in second half = Sequence E = 0
-                                       Demod.bitCount++;
-                                       Demod.shiftReg = (Demod.shiftReg >> 1);                         // add a 0 to the shiftreg
-                                       if(Demod.bitCount >= 9) {                                                       // if we decoded a full byte (including parity)
-                                               Demod.parityBits <<= 1;                                                 // make room for the new parity bit
-                                               Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
-                                               Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
-                                               Demod.bitCount = 0;
-                                               Demod.shiftReg = 0;
-                                       }
-                               } else {                                                                                                // no modulation in both halves - End of communication
+                               if (Demod.len > 0 || Demod.bitCount > 0) {                              // received something
                                        if(Demod.bitCount > 0) {                                                        // if we decoded bits
                                                Demod.shiftReg >>= (9 - Demod.bitCount);                // add the remaining decoded bits to the output
                                                Demod.output[Demod.len++] = Demod.shiftReg & 0xff;
                                                // No parity bit, so just shift a 0
                                                Demod.parityBits <<= 1;
                                        }
-                                       Demod.state = DEMOD_UNSYNCD;                                            // start from the beginning
                                        return TRUE;                                                                            // we are finished with decoding the raw data sequence
+                               } else {                                                                                                // nothing received. Start over
+                                       DemodReset();
                                }
                        }
+               }
                        
        } 
 
@@ -570,8 +526,8 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
        // a good trigger condition to get started is probably when we see a
        // response from the tag.
        // triggered == FALSE -- to wait first for card
-       int triggered = !(param & 0x03); 
-
+       bool triggered = !(param & 0x03); 
+       
        // The command (reader -> tag) that we're receiving.
        // The length of a received command will in most cases be no more than 18 bytes.
        // So 32 should be enough!
@@ -584,40 +540,31 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
        //uint8_t *trace = (uint8_t *)BigBuf;
        
        // The DMA buffer, used to stream samples from the FPGA
-       int8_t *dmaBuf = ((int8_t *)BigBuf) + DMA_BUFFER_OFFSET;
-       int8_t *data = dmaBuf;
+       uint8_t *dmaBuf = ((uint8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+       uint8_t *data = dmaBuf;
+       uint8_t previous_data = 0;
        int maxDataLen = 0;
        int dataLen = 0;
+       bool TagIsActive = FALSE;
+       bool ReaderIsActive = FALSE;
+       
+       iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
 
        // Set up the demodulator for tag -> reader responses.
        Demod.output = receivedResponse;
-       Demod.len = 0;
-       Demod.state = DEMOD_UNSYNCD;
 
        // Set up the demodulator for the reader -> tag commands
-       memset(&Uart, 0, sizeof(Uart));
        Uart.output = receivedCmd;
-       Uart.byteCntMax = 32;                        // was 100 (greg)//////////////////
-       Uart.state = STATE_UNSYNCD;
 
-       // Setup for the DMA.
-       FpgaSetupSsc();
+       // Setup and start DMA.
        FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
-
-       // And put the FPGA in the appropriate mode
-       // Signal field is off with the appropriate LED
-       LED_D_OFF();
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_SNIFFER);
-       SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-
-       // Count of samples received so far, so that we can include timing
-       // information in the trace buffer.
-       rsamples = 0;
+       
        // And now we loop, receiving samples.
-       while(true) {
+       for(uint32_t rsamples = 0; TRUE; ) {
+
                if(BUTTON_PRESS()) {
                        DbpString("cancelled by button");
-                       goto done;
+                       break;
                }
 
                LED_A_ON();
@@ -628,14 +575,14 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
                if (readBufDataP <= dmaBufDataP){
                        dataLen = dmaBufDataP - readBufDataP;
                } else {
-                       dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP + 1;
+                       dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP;
                }
                // test for length of buffer
                if(dataLen > maxDataLen) {
                        maxDataLen = dataLen;
                        if(dataLen > 400) {
-                               Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
-                               goto done;
+                               Dbprintf("blew circular buffer! dataLen=%d", dataLen);
+                               break;
                        }
                }
                if(dataLen < 1) continue;
@@ -644,6 +591,7 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
                if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
                        AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
                        AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
+                       Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
                }
                // secondary buffer sets as primary, secondary buffer was stopped
                if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
@@ -652,39 +600,51 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
                }
 
                LED_A_OFF();
-               if(MF_DBGLEVEL > 4) Dbprintf("1:%d",dataLen);
-               rsamples += 4;
-               if(MillerDecoding((data[0] & 0xF0) >> 4)) {
-                       LED_C_ON();
+               
+               if (rsamples & 0x01) {                          // Need two samples to feed Miller and Manchester-Decoder
 
-                       // check - if there is a short 7bit request from reader
-                       if ((!triggered) && (param & 0x02) && (Uart.byteCnt == 1) && (Uart.bitCnt = 9)) triggered = TRUE;
+                       if(!TagIsActive) {              // no need to try decoding reader data if the tag is sending
+                               uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
+                               if (MillerDecoding(readerdata, (rsamples-1)*4)) {
+                                       LED_C_ON();
 
-                       if(triggered) {
-                               if (!LogTrace(receivedCmd, Uart.byteCnt, 0 - Uart.samples, Uart.parityBits, TRUE)) break;
+                                       // check - if there is a short 7bit request from reader
+                                       if ((!triggered) && (param & 0x02) && (Uart.len == 1) && (Uart.bitCount == 7)) triggered = TRUE;
+
+                                       if(triggered) {
+                                               if (!LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER, Uart.parityBits, TRUE)) break;
+                                               if (!LogTrace(NULL, 0, Uart.endTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER, 0, TRUE)) break;
+                                       }
+                                       /* And ready to receive another command. */
+                                       UartReset();
+                                       /* And also reset the demod code, which might have been */
+                                       /* false-triggered by the commands from the reader. */
+                                       DemodReset();
+                                       LED_B_OFF();
+                               }
+                               ReaderIsActive = (Uart.state != STATE_UNSYNCD);
                        }
-                       /* And ready to receive another command. */
-                       Uart.state = STATE_UNSYNCD;
-                       /* And also reset the demod code, which might have been */
-                       /* false-triggered by the commands from the reader. */
-                       Demod.state = DEMOD_UNSYNCD;
-                       LED_B_OFF();
-               }
-               if(MF_DBGLEVEL > 4) Dbprintf("2");
-               if(ManchesterDecoding(data[0], 0)) {
-                       LED_B_ON();
 
-                       if (!LogTrace(receivedResponse, Demod.len, 0 - Demod.samples, Demod.parityBits, FALSE)) break;
+                       if(!ReaderIsActive) {           // no need to try decoding tag data if the reader is sending - and we cannot afford the time
+                               uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
+                               if(ManchesterDecoding(tagdata, 0, (rsamples-1)*4)) {
+                                       LED_B_ON();
 
-                       if ((!triggered) && (param & 0x01)) triggered = TRUE;
+                                       if (!LogTrace(receivedResponse, Demod.len, Demod.startTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER, Demod.parityBits, FALSE)) break;
+                                       if (!LogTrace(NULL, 0, Demod.endTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER, 0, FALSE)) break;
 
-                       // And ready to receive another response.
-                       memset(&Demod, 0, sizeof(Demod));
-                       Demod.output = receivedResponse;
-                       Demod.state = DEMOD_UNSYNCD;
-                       LED_C_OFF();
+                                       if ((!triggered) && (param & 0x01)) triggered = TRUE;
+
+                                       // And ready to receive another response.
+                                       DemodReset();
+                                       LED_C_OFF();
+                               } 
+                               TagIsActive = (Demod.state != DEMOD_UNSYNCD);
+                       }
                }
 
+               previous_data = *data;
+               rsamples++;
                data++;
                if(data > dmaBuf + DMA_BUFFER_SIZE) {
                        data = dmaBuf;
@@ -693,10 +653,9 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 
        DbpString("COMMAND FINISHED");
 
-done:
-       AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
-       Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.byteCnt=%x", maxDataLen, Uart.state, Uart.byteCnt);
-       Dbprintf("Uart.byteCntMax=%x, traceLen=%x, Uart.output[0]=%08x", Uart.byteCntMax, traceLen, (int)Uart.output[0]);
+       FpgaDisableSscDma();
+       Dbprintf("maxDataLen=%d, Uart.state=%x, Uart.len=%d", maxDataLen, Uart.state, Uart.len);
+       Dbprintf("traceLen=%d, Uart.output[0]=%08x", traceLen, (uint32_t)Uart.output[0]);
        LEDsoff();
 }
 
@@ -721,6 +680,7 @@ static void CodeIso14443aAsTagPar(const uint8_t *cmd, int len, uint32_t dwParity
        
        // Send startbit
        ToSend[++ToSendMax] = SEC_D;
+       LastProxToAirDuration = 8 * ToSendMax - 4;
 
        for(i = 0; i < len; i++) {
                int j;
@@ -739,8 +699,10 @@ static void CodeIso14443aAsTagPar(const uint8_t *cmd, int len, uint32_t dwParity
                // Get the parity bit
                if ((dwParity >> i) & 0x01) {
                        ToSend[++ToSendMax] = SEC_D;
+                       LastProxToAirDuration = 8 * ToSendMax - 4;
                } else {
                        ToSend[++ToSendMax] = SEC_E;
+                       LastProxToAirDuration = 8 * ToSendMax;
                }
        }
 
@@ -755,48 +717,6 @@ static void CodeIso14443aAsTag(const uint8_t *cmd, int len){
        CodeIso14443aAsTagPar(cmd, len, GetParity(cmd, len));
 }
 
-////-----------------------------------------------------------------------------
-//// This is to send a NACK kind of answer, its only 3 bits, I know it should be 4
-////-----------------------------------------------------------------------------
-//static void CodeStrangeAnswerAsTag()
-//{
-//     int i;
-//
-//     ToSendReset();
-//
-//     // Correction bit, might be removed when not needed
-//     ToSendStuffBit(0);
-//     ToSendStuffBit(0);
-//     ToSendStuffBit(0);
-//     ToSendStuffBit(0);
-//     ToSendStuffBit(1);  // 1
-//     ToSendStuffBit(0);
-//     ToSendStuffBit(0);
-//     ToSendStuffBit(0);
-//
-//     // Send startbit
-//     ToSend[++ToSendMax] = SEC_D;
-//
-//     // 0
-//     ToSend[++ToSendMax] = SEC_E;
-//
-//     // 0
-//     ToSend[++ToSendMax] = SEC_E;
-//
-//     // 1
-//     ToSend[++ToSendMax] = SEC_D;
-//
-//     // Send stopbit
-//     ToSend[++ToSendMax] = SEC_F;
-//
-//     // Flush the buffer in FPGA!!
-//     for(i = 0; i < 5; i++) {
-//             ToSend[++ToSendMax] = SEC_F;
-//     }
-//
-//     // Convert from last byte pos to length
-//     ToSendMax++;
-//}
 
 static void Code4bitAnswerAsTag(uint8_t cmd)
 {
@@ -821,8 +741,10 @@ static void Code4bitAnswerAsTag(uint8_t cmd)
        for(i = 0; i < 4; i++) {
                if(b & 1) {
                        ToSend[++ToSendMax] = SEC_D;
+                       LastProxToAirDuration = 8 * ToSendMax - 4;
                } else {
                        ToSend[++ToSendMax] = SEC_E;
+                       LastProxToAirDuration = 8 * ToSendMax;
                }
                b >>= 1;
        }
@@ -830,11 +752,6 @@ static void Code4bitAnswerAsTag(uint8_t cmd)
        // Send stopbit
        ToSend[++ToSendMax] = SEC_F;
 
-       // Flush the buffer in FPGA!!
-       for(i = 0; i < 5; i++) {
-               ToSend[++ToSendMax] = SEC_F;
-       }
-
        // Convert from last byte pos to length
        ToSendMax++;
 }
@@ -853,40 +770,37 @@ static int GetIso14443aCommandFromReader(uint8_t *received, int *len, int maxLen
     FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
 
     // Now run a `software UART' on the stream of incoming samples.
+       UartReset();
     Uart.output = received;
-    Uart.byteCntMax = maxLen;
-    Uart.state = STATE_UNSYNCD;
+
+       // clear RXRDY:
+    uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 
     for(;;) {
         WDT_HIT();
 
         if(BUTTON_PRESS()) return FALSE;
-
-        if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-            AT91C_BASE_SSC->SSC_THR = 0x00;
-        }
+               
         if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-            uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-                       if(MillerDecoding((b & 0xf0) >> 4)) {
-                               *len = Uart.byteCnt;
+            b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+                       if(MillerDecoding(b, 0)) {
+                               *len = Uart.len;
                                return TRUE;
                        }
-                       if(MillerDecoding(b & 0x0f)) {
-                               *len = Uart.byteCnt;
-                               return TRUE;
-                       }
-        }
+               }
     }
 }
 
-static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, int correctionNeeded);
-int EmSend4bitEx(uint8_t resp, int correctionNeeded);
+static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, bool correctionNeeded);
+int EmSend4bitEx(uint8_t resp, bool correctionNeeded);
 int EmSend4bit(uint8_t resp);
-int EmSendCmdExPar(uint8_t *resp, int respLen, int correctionNeeded, uint32_t par);
-int EmSendCmdExPar(uint8_t *resp, int respLen, int correctionNeeded, uint32_t par);
-int EmSendCmdEx(uint8_t *resp, int respLen, int correctionNeeded);
+int EmSendCmdExPar(uint8_t *resp, int respLen, bool correctionNeeded, uint32_t par);
+int EmSendCmdExPar(uint8_t *resp, int respLen, bool correctionNeeded, uint32_t par);
+int EmSendCmdEx(uint8_t *resp, int respLen, bool correctionNeeded);
 int EmSendCmd(uint8_t *resp, int respLen);
 int EmSendCmdPar(uint8_t *resp, int respLen, uint32_t par);
+bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint32_t reader_Parity,
+                                uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint32_t tag_Parity);
 
 static uint8_t* free_buffer_pointer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
 
@@ -895,6 +809,7 @@ typedef struct {
   size_t   response_n;
   uint8_t* modulation;
   size_t   modulation_n;
+  uint32_t ProxToAirDuration;
 } tag_response_info_t;
 
 void reset_free_buffer() {
@@ -902,7 +817,7 @@ void reset_free_buffer() {
 }
 
 bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffer_size) {
-       // Exmaple response, answer to MIFARE Classic read block will be 16 bytes + 2 CRC = 18 bytes
+       // Example response, answer to MIFARE Classic read block will be 16 bytes + 2 CRC = 18 bytes
        // This will need the following byte array for a modulation sequence
        //    144        data bits (18 * 8)
        //     18        parity bits
@@ -926,8 +841,9 @@ bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffe
   // Copy the byte array, used for this modulation to the buffer position
   memcpy(response_info->modulation,ToSend,ToSendMax);
   
-  // Store the number of bytes that were used for encoding/modulation
+  // Store the number of bytes that were used for encoding/modulation and the time needed to transfer them
   response_info->modulation_n = ToSendMax;
+  response_info->ProxToAirDuration = LastProxToAirDuration;
   
   return true;
 }
@@ -956,10 +872,9 @@ bool prepare_allocated_tag_modulation(tag_response_info_t* response_info) {
 void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 {
        // Enable and clear the trace
-       tracing = TRUE;
        iso14a_clear_trace();
+       iso14a_set_tracing(TRUE);
 
-       // This function contains the tag emulation
        uint8_t sak;
 
        // The first response contains the ATQA (note: bytes are transmitted in reverse order).
@@ -1034,41 +949,41 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
        uint8_t response6[] = { 0x04, 0x58, 0x00, 0x02, 0x00, 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS
        ComputeCrc14443(CRC_14443_A, response6, 4, &response6[4], &response6[5]);
 
-  #define TAG_RESPONSE_COUNT 7
-  tag_response_info_t responses[TAG_RESPONSE_COUNT] = {
-    { .response = response1,  .response_n = sizeof(response1)  },  // Answer to request - respond with card type
-    { .response = response2,  .response_n = sizeof(response2)  },  // Anticollision cascade1 - respond with uid
-    { .response = response2a, .response_n = sizeof(response2a) },  // Anticollision cascade2 - respond with 2nd half of uid if asked
-    { .response = response3,  .response_n = sizeof(response3)  },  // Acknowledge select - cascade 1
-    { .response = response3a, .response_n = sizeof(response3a) },  // Acknowledge select - cascade 2
-    { .response = response5,  .response_n = sizeof(response5)  },  // Authentication answer (random nonce)
-    { .response = response6,  .response_n = sizeof(response6)  },  // dummy ATS (pseudo-ATR), answer to RATS
-  };
-
-  // Allocate 512 bytes for the dynamic modulation, created when the reader querries for it
-  // Such a response is less time critical, so we can prepare them on the fly
-  #define DYNAMIC_RESPONSE_BUFFER_SIZE 64
-  #define DYNAMIC_MODULATION_BUFFER_SIZE 512
-  uint8_t dynamic_response_buffer[DYNAMIC_RESPONSE_BUFFER_SIZE];
-  uint8_t dynamic_modulation_buffer[DYNAMIC_MODULATION_BUFFER_SIZE];
-  tag_response_info_t dynamic_response_info = {
-    .response = dynamic_response_buffer,
-    .response_n = 0,
-    .modulation = dynamic_modulation_buffer,
-    .modulation_n = 0
-  };
+       #define TAG_RESPONSE_COUNT 7
+       tag_response_info_t responses[TAG_RESPONSE_COUNT] = {
+               { .response = response1,  .response_n = sizeof(response1)  },  // Answer to request - respond with card type
+               { .response = response2,  .response_n = sizeof(response2)  },  // Anticollision cascade1 - respond with uid
+               { .response = response2a, .response_n = sizeof(response2a) },  // Anticollision cascade2 - respond with 2nd half of uid if asked
+               { .response = response3,  .response_n = sizeof(response3)  },  // Acknowledge select - cascade 1
+               { .response = response3a, .response_n = sizeof(response3a) },  // Acknowledge select - cascade 2
+               { .response = response5,  .response_n = sizeof(response5)  },  // Authentication answer (random nonce)
+               { .response = response6,  .response_n = sizeof(response6)  },  // dummy ATS (pseudo-ATR), answer to RATS
+       };
+
+       // Allocate 512 bytes for the dynamic modulation, created when the reader queries for it
+       // Such a response is less time critical, so we can prepare them on the fly
+       #define DYNAMIC_RESPONSE_BUFFER_SIZE 64
+       #define DYNAMIC_MODULATION_BUFFER_SIZE 512
+       uint8_t dynamic_response_buffer[DYNAMIC_RESPONSE_BUFFER_SIZE];
+       uint8_t dynamic_modulation_buffer[DYNAMIC_MODULATION_BUFFER_SIZE];
+       tag_response_info_t dynamic_response_info = {
+               .response = dynamic_response_buffer,
+               .response_n = 0,
+               .modulation = dynamic_modulation_buffer,
+               .modulation_n = 0
+       };
   
-  // Reset the offset pointer of the free buffer
-  reset_free_buffer();
+       // Reset the offset pointer of the free buffer
+       reset_free_buffer();
   
-  // Prepare the responses of the anticollision phase
+       // Prepare the responses of the anticollision phase
        // there will be not enough time to do this at the moment the reader sends it REQA
-  for (size_t i=0; i<TAG_RESPONSE_COUNT; i++) {
-    prepare_allocated_tag_modulation(&responses[i]);
-  }
+       for (size_t i=0; i<TAG_RESPONSE_COUNT; i++) {
+               prepare_allocated_tag_modulation(&responses[i]);
+       }
 
        uint8_t *receivedCmd = (((uint8_t *)BigBuf) + RECV_CMD_OFFSET);
-       int len;
+       int len = 0;
 
        // To control where we are in the protocol
        int order = 0;
@@ -1080,28 +995,22 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
        int cmdsRecvd = 0;
 
        // We need to listen to the high-frequency, peak-detected path.
-       SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-       FpgaSetupSsc();
+       iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
 
        cmdsRecvd = 0;
-  tag_response_info_t* p_response;
+       tag_response_info_t* p_response;
 
        LED_A_ON();
        for(;;) {
-    // Clean receive command buffer
-    memset(receivedCmd, 0x44, RECV_CMD_SIZE);
-       
+               // Clean receive command buffer
+               
                if(!GetIso14443aCommandFromReader(receivedCmd, &len, RECV_CMD_SIZE)) {
                        DbpString("Button press");
                        break;
                }
-    
-               if (tracing) {
-                       LogTrace(receivedCmd,len, 0, Uart.parityBits, TRUE);
-               }
-    
-    p_response = NULL;
-    
+
+               p_response = NULL;
+               
                // doob - added loads of debug strings so we can see what the reader is saying to us during the sim as hi14alist is not populated
                // Okay, look at the command now.
                lastorder = order;
@@ -1119,79 +1028,100 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
                        p_response = &responses[4]; order = 30;
                } else if(receivedCmd[0] == 0x30) {     // Received a (plain) READ
                        EmSendCmdEx(data+(4*receivedCmd[0]),16,false);
-                       Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);
+                       // Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);
                        // We already responded, do not send anything with the EmSendCmd14443aRaw() that is called below
-      p_response = NULL;
+                       p_response = NULL;
                } else if(receivedCmd[0] == 0x50) {     // Received a HALT
 //                     DbpString("Reader requested we HALT!:");
-      p_response = NULL;
+                       if (tracing) {
+                               LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                               LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+                       }
+                       p_response = NULL;
                } else if(receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61) {   // Received an authentication request
                        p_response = &responses[5]; order = 7;
                } else if(receivedCmd[0] == 0xE0) {     // Received a RATS request
-                       p_response = &responses[6]; order = 70;
-               } else if (order == 7 && len ==8) { // Received authentication request
-      uint32_t nr = bytes_to_num(receivedCmd,4);
-      uint32_t ar = bytes_to_num(receivedCmd+4,4);
-      Dbprintf("Auth attempt {nr}{ar}: %08x %08x",nr,ar);
-    } else {
-      // Check for ISO 14443A-4 compliant commands, look at left nibble
-      switch (receivedCmd[0]) {
-
-        case 0x0B:
-        case 0x0A: { // IBlock (command)
-          dynamic_response_info.response[0] = receivedCmd[0];
-          dynamic_response_info.response[1] = 0x00;
-          dynamic_response_info.response[2] = 0x90;
-          dynamic_response_info.response[3] = 0x00;
-          dynamic_response_info.response_n = 4;
-        } break;
-
-        case 0x1A:
-        case 0x1B: { // Chaining command
-          dynamic_response_info.response[0] = 0xaa | ((receivedCmd[0]) & 1);
-          dynamic_response_info.response_n = 2;
-        } break;
-
-        case 0xaa:
-        case 0xbb: {
-          dynamic_response_info.response[0] = receivedCmd[0] ^ 0x11;
-          dynamic_response_info.response_n = 2;
-        } break;
-          
-        case 0xBA: { //
-          memcpy(dynamic_response_info.response,"\xAB\x00",2);
-          dynamic_response_info.response_n = 2;
-        } break;
-
-        case 0xCA:
-        case 0xC2: { // Readers sends deselect command
-          memcpy(dynamic_response_info.response,"\xCA\x00",2);
-          dynamic_response_info.response_n = 2;
-        } break;
-
-        default: {
-          // Never seen this command before
-          Dbprintf("Received unknown command (len=%d):",len);
-          Dbhexdump(len,receivedCmd,false);
-          // Do not respond
-          dynamic_response_info.response_n = 0;
-        } break;
-      }
+                       if (tagType == 1 || tagType == 2) {     // RATS not supported
+                               EmSend4bit(CARD_NACK_NA);
+                               p_response = NULL;
+                       } else {
+                               p_response = &responses[6]; order = 70;
+                       }
+               } else if (order == 7 && len == 8) { // Received authentication request
+                       if (tracing) {
+                               LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                               LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+                       }
+                       uint32_t nr = bytes_to_num(receivedCmd,4);
+                       uint32_t ar = bytes_to_num(receivedCmd+4,4);
+                       Dbprintf("Auth attempt {nr}{ar}: %08x %08x",nr,ar);
+               } else {
+                       // Check for ISO 14443A-4 compliant commands, look at left nibble
+                       switch (receivedCmd[0]) {
+
+                               case 0x0B:
+                               case 0x0A: { // IBlock (command)
+                                 dynamic_response_info.response[0] = receivedCmd[0];
+                                 dynamic_response_info.response[1] = 0x00;
+                                 dynamic_response_info.response[2] = 0x90;
+                                 dynamic_response_info.response[3] = 0x00;
+                                 dynamic_response_info.response_n = 4;
+                               } break;
+
+                               case 0x1A:
+                               case 0x1B: { // Chaining command
+                                 dynamic_response_info.response[0] = 0xaa | ((receivedCmd[0]) & 1);
+                                 dynamic_response_info.response_n = 2;
+                               } break;
+
+                               case 0xaa:
+                               case 0xbb: {
+                                 dynamic_response_info.response[0] = receivedCmd[0] ^ 0x11;
+                                 dynamic_response_info.response_n = 2;
+                               } break;
+                                 
+                               case 0xBA: { //
+                                 memcpy(dynamic_response_info.response,"\xAB\x00",2);
+                                 dynamic_response_info.response_n = 2;
+                               } break;
+
+                               case 0xCA:
+                               case 0xC2: { // Readers sends deselect command
+                                 memcpy(dynamic_response_info.response,"\xCA\x00",2);
+                                 dynamic_response_info.response_n = 2;
+                               } break;
+
+                               default: {
+                                       // Never seen this command before
+                                       if (tracing) {
+                                               LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                               LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+                                       }
+                                       Dbprintf("Received unknown command (len=%d):",len);
+                                       Dbhexdump(len,receivedCmd,false);
+                                       // Do not respond
+                                       dynamic_response_info.response_n = 0;
+                               } break;
+                       }
       
-      if (dynamic_response_info.response_n > 0) {
-        // Copy the CID from the reader query
-        dynamic_response_info.response[1] = receivedCmd[1];
+                       if (dynamic_response_info.response_n > 0) {
+                               // Copy the CID from the reader query
+                               dynamic_response_info.response[1] = receivedCmd[1];
 
-        // Add CRC bytes, always used in ISO 14443A-4 compliant cards
-        AppendCrc14443a(dynamic_response_info.response,dynamic_response_info.response_n);
-        dynamic_response_info.response_n += 2;
+                               // Add CRC bytes, always used in ISO 14443A-4 compliant cards
+                               AppendCrc14443a(dynamic_response_info.response,dynamic_response_info.response_n);
+                               dynamic_response_info.response_n += 2;
         
-        if (prepare_tag_modulation(&dynamic_response_info,DYNAMIC_MODULATION_BUFFER_SIZE) == false) {
-          Dbprintf("Error preparing tag response");
-          break;
-        }
-        p_response = &dynamic_response_info;
-      }
+                               if (prepare_tag_modulation(&dynamic_response_info,DYNAMIC_MODULATION_BUFFER_SIZE) == false) {
+                                       Dbprintf("Error preparing tag response");
+                                       if (tracing) {
+                                               LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                               LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+                                       }
+                                       break;
+                               }
+                               p_response = &dynamic_response_info;
+                       }
                }
 
                // Count number of wakeups received after a halt
@@ -1200,12 +1130,6 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
                // Count number of other messages after a halt
                if(order != 6 && lastorder == 5) { happened2++; }
 
-               // Look at last parity bit to determine timing of answer
-               if((Uart.parityBits & 0x01) || receivedCmd[0] == 0x52) {
-                       // 1236, so correction bit needed
-                       //i = 0;
-               }
-
                if(cmdsRecvd > 999) {
                        DbpString("1000 commands later...");
                        break;
@@ -1213,16 +1137,25 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
                cmdsRecvd++;
 
                if (p_response != NULL) {
-      EmSendCmd14443aRaw(p_response->modulation, p_response->modulation_n, receivedCmd[0] == 0x52);
-      if (tracing) {
-        LogTrace(p_response->response,p_response->response_n,0,SwapBits(GetParity(p_response->response,p_response->response_n),p_response->response_n),FALSE);
-        if(traceLen > TRACE_SIZE) {
-          DbpString("Trace full");
-//          break;
-        }
-      }
-    }
-  }
+                       EmSendCmd14443aRaw(p_response->modulation, p_response->modulation_n, receivedCmd[0] == 0x52);
+                       // do the tracing for the previous reader request and this tag answer:
+                       EmLogTrace(Uart.output, 
+                                               Uart.len, 
+                                               Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, 
+                                               Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 
+                                               Uart.parityBits,
+                                               p_response->response, 
+                                               p_response->response_n,
+                                               LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
+                                               (LastTimeProxToAirStart + p_response->ProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG, 
+                                               SwapBits(GetParity(p_response->response, p_response->response_n), p_response->response_n));
+               }
+               
+               if (!tracing) {
+                       Dbprintf("Trace Full. Simulation stopped.");
+                       break;
+               }
+       }
 
        Dbprintf("%x %x %x", happened, happened2, cmdsRecvd);
        LED_A_OFF();
@@ -1242,7 +1175,7 @@ void PrepareDelayedTransfer(uint16_t delay)
                for (uint16_t i = 0; i < delay; i++) {
                        bitmask |= (0x01 << i);
                }
-               ToSend[++ToSendMax] = 0x00;
+               ToSend[ToSendMax++] = 0x00;
                for (uint16_t i = 0; i < ToSendMax; i++) {
                        bits_to_shift = ToSend[i] & bitmask;
                        ToSend[i] = ToSend[i] >> delay;
@@ -1252,38 +1185,48 @@ void PrepareDelayedTransfer(uint16_t delay)
        }
 }
 
-//-----------------------------------------------------------------------------
+
+//-------------------------------------------------------------------------------------
 // Transmit the command (to the tag) that was placed in ToSend[].
 // Parameter timing:
-// if NULL: ignored
-// if == 0:    return time of transfer
+// if NULL: transfer at next possible time, taking into account
+//                     request guard time and frame delay time
+// if == 0:    transfer immediately and return time of transfer
 // if != 0: delay transfer until time specified
-//-----------------------------------------------------------------------------
+//-------------------------------------------------------------------------------------
 static void TransmitFor14443a(const uint8_t *cmd, int len, uint32_t *timing)
 {
-       int c;
-
+       
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
 
+       uint32_t ThisTransferTime = 0;
 
        if (timing) {
                if(*timing == 0) {                                                                              // Measure time
-                       *timing = (GetCountMifare() + 8) & 0xfffffff8;
+                       *timing = (GetCountSspClk() + 8) & 0xfffffff8;
                } else {
                        PrepareDelayedTransfer(*timing & 0x00000007);           // Delay transfer (fine tuning - up to 7 MF clock ticks)
                }
-               if(MF_DBGLEVEL >= 4 && GetCountMifare() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");
-               while(GetCountMifare() < (*timing & 0xfffffff8));               // Delay transfer (multiple of 8 MF clock ticks)
-       }
-
-       for(c = 0; c < 10;) {   // standard delay for each transfer (allow tag to be ready after last transmission?)
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                       AT91C_BASE_SSC->SSC_THR = 0x00; 
-                       c++;
-               }
+               if(MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");
+               while(GetCountSspClk() < (*timing & 0xfffffff8));               // Delay transfer (multiple of 8 MF clock ticks)
+               LastTimeProxToAirStart = *timing;
+       } else {
+               ThisTransferTime = ((MAX(NextTransferTime, GetCountSspClk()) & 0xfffffff8) + 8);
+               while(GetCountSspClk() < ThisTransferTime);
+               LastTimeProxToAirStart = ThisTransferTime;
        }
        
-       c = 0;
+       // clear TXRDY
+       AT91C_BASE_SSC->SSC_THR = SEC_Y;
+
+       // for(uint16_t c = 0; c < 10;) {       // standard delay for each transfer (allow tag to be ready after last transmission)
+               // if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+                       // AT91C_BASE_SSC->SSC_THR = SEC_Y;     
+                       // c++;
+               // }
+       // }
+
+       uint16_t c = 0;
        for(;;) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = cmd[c];
@@ -1293,88 +1236,91 @@ static void TransmitFor14443a(const uint8_t *cmd, int len, uint32_t *timing)
                        }
                }
        }
-
+       
+       NextTransferTime = MAX(NextTransferTime, LastTimeProxToAirStart + REQUEST_GUARD_TIME);
+       
 }
 
+
 //-----------------------------------------------------------------------------
 // Prepare reader command (in bits, support short frames) to send to FPGA
 //-----------------------------------------------------------------------------
 void CodeIso14443aBitsAsReaderPar(const uint8_t * cmd, int bits, uint32_t dwParity)
 {
-  int i, j;
-  int last;
-  uint8_t b;
-
-  ToSendReset();
-
-  // Start of Communication (Seq. Z)
-  ToSend[++ToSendMax] = SEC_Z;
-  last = 0;
-
-  size_t bytecount = nbytes(bits);
-  // Generate send structure for the data bits
-  for (i = 0; i < bytecount; i++) {
-    // Get the current byte to send
-    b = cmd[i];
-    size_t bitsleft = MIN((bits-(i*8)),8);
-
-    for (j = 0; j < bitsleft; j++) {
-      if (b & 1) {
-        // Sequence X
-         ToSend[++ToSendMax] = SEC_X;
-        last = 1;
-      } else {
-        if (last == 0) {
-          // Sequence Z
-               ToSend[++ToSendMax] = SEC_Z;
-        } else {
-          // Sequence Y
-               ToSend[++ToSendMax] = SEC_Y;
-          last = 0;
-        }
-      }
-      b >>= 1;
-    }
+       int i, j;
+       int last;
+       uint8_t b;
 
-    // Only transmit (last) parity bit if we transmitted a complete byte
-    if (j == 8) {
-      // Get the parity bit
-      if ((dwParity >> i) & 0x01) {
-        // Sequence X
-        ToSend[++ToSendMax] = SEC_X;
-        last = 1;
-      } else {
-        if (last == 0) {
-          // Sequence Z
-          ToSend[++ToSendMax] = SEC_Z;
-        } else {
-          // Sequence Y
-          ToSend[++ToSendMax] = SEC_Y;
-          last = 0;
-        }
-      }
-    }
-  }
+       ToSendReset();
 
-  // End of Communication
-  if (last == 0) {
-    // Sequence Z
-         ToSend[++ToSendMax] = SEC_Z;
-  } else {
-    // Sequence Y
-         ToSend[++ToSendMax] = SEC_Y;
-    last = 0;
-  }
-  // Sequence Y
-  ToSend[++ToSendMax] = SEC_Y;
+       // Start of Communication (Seq. Z)
+       ToSend[++ToSendMax] = SEC_Z;
+       LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
+       last = 0;
+
+       size_t bytecount = nbytes(bits);
+       // Generate send structure for the data bits
+       for (i = 0; i < bytecount; i++) {
+               // Get the current byte to send
+               b = cmd[i];
+               size_t bitsleft = MIN((bits-(i*8)),8);
+
+               for (j = 0; j < bitsleft; j++) {
+                       if (b & 1) {
+                               // Sequence X
+                               ToSend[++ToSendMax] = SEC_X;
+                               LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
+                               last = 1;
+                       } else {
+                               if (last == 0) {
+                               // Sequence Z
+                               ToSend[++ToSendMax] = SEC_Z;
+                               LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
+                               } else {
+                                       // Sequence Y
+                                       ToSend[++ToSendMax] = SEC_Y;
+                                       last = 0;
+                               }
+                       }
+                       b >>= 1;
+               }
+
+               // Only transmit (last) parity bit if we transmitted a complete byte
+               if (j == 8) {
+                       // Get the parity bit
+                       if ((dwParity >> i) & 0x01) {
+                               // Sequence X
+                               ToSend[++ToSendMax] = SEC_X;
+                               LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
+                               last = 1;
+                       } else {
+                               if (last == 0) {
+                                       // Sequence Z
+                                       ToSend[++ToSendMax] = SEC_Z;
+                                       LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
+                               } else {
+                                       // Sequence Y
+                                       ToSend[++ToSendMax] = SEC_Y;
+                                       last = 0;
+                               }
+                       }
+               }
+       }
 
-  // Just to be sure!
-  ToSend[++ToSendMax] = SEC_Y;
-  ToSend[++ToSendMax] = SEC_Y;
-  ToSend[++ToSendMax] = SEC_Y;
+       // End of Communication: Logic 0 followed by Sequence Y
+       if (last == 0) {
+               // Sequence Z
+               ToSend[++ToSendMax] = SEC_Z;
+               LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
+       } else {
+               // Sequence Y
+               ToSend[++ToSendMax] = SEC_Y;
+               last = 0;
+       }
+       ToSend[++ToSendMax] = SEC_Y;
 
-  // Convert from last character reference to length
-  ToSendMax++;
+       // Convert to length of command:
+       ToSendMax++;
 }
 
 //-----------------------------------------------------------------------------
@@ -1390,7 +1336,7 @@ void CodeIso14443aAsReaderPar(const uint8_t * cmd, int len, uint32_t dwParity)
 // Stop when button is pressed (return 1) or field was gone (return 2)
 // Or return 0 when command is captured
 //-----------------------------------------------------------------------------
-static int EmGetCmd(uint8_t *received, int *len, int maxLen)
+static int EmGetCmd(uint8_t *received, int *len)
 {
        *len = 0;
 
@@ -1415,9 +1361,11 @@ static int EmGetCmd(uint8_t *received, int *len, int maxLen)
        AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
        
        // Now run a 'software UART' on the stream of incoming samples.
+       UartReset();
        Uart.output = received;
-       Uart.byteCntMax = maxLen;
-       Uart.state = STATE_UNSYNCD;
+
+       // Clear RXRDY:
+    uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 
        for(;;) {
                WDT_HIT();
@@ -1441,98 +1389,157 @@ static int EmGetCmd(uint8_t *received, int *len, int maxLen)
                                analogAVG = 0;
                        }
                }
-               // transmit none
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                       AT91C_BASE_SSC->SSC_THR = 0x00;
-               }
+
                // receive and test the miller decoding
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                       volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-                       if(MillerDecoding((b & 0xf0) >> 4)) {
-                               *len = Uart.byteCnt;
-                               if (tracing) LogTrace(received, *len, GetDeltaCountUS(), Uart.parityBits, TRUE);
-                               return 0;
-                       }
-                       if(MillerDecoding(b & 0x0f)) {
-                               *len = Uart.byteCnt;
-                               if (tracing) LogTrace(received, *len, GetDeltaCountUS(), Uart.parityBits, TRUE);
+        if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+            b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+                       if(MillerDecoding(b, 0)) {
+                               *len = Uart.len;
                                return 0;
                        }
-               }
+        }
+
        }
 }
 
-static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, int correctionNeeded)
-{
-       int i, u = 0;
-       uint8_t b = 0;
 
+static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, bool correctionNeeded)
+{
+       uint8_t b;
+       uint16_t i = 0;
+       uint32_t ThisTransferTime;
+       
        // Modulate Manchester
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_MOD);
-       AT91C_BASE_SSC->SSC_THR = 0x00;
-       FpgaSetupSsc();
-       
-       // include correction bit
-       i = 1;
-       if((Uart.parityBits & 0x01) || correctionNeeded) {
+
+       // include correction bit if necessary
+       if (Uart.parityBits & 0x01) {
+               correctionNeeded = TRUE;
+       }
+       if(correctionNeeded) {
                // 1236, so correction bit needed
                i = 0;
+       } else {
+               i = 1;
        }
+
+       // clear receiving shift register and holding register
+       while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+       b = AT91C_BASE_SSC->SSC_RHR; (void) b;
+       while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+       b = AT91C_BASE_SSC->SSC_RHR; (void) b;
        
+       // wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line)
+       for (uint16_t j = 0; j < 5; j++) {      // allow timeout - better late than never
+               while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+               if (AT91C_BASE_SSC->SSC_RHR) break;
+       }
+
+       while ((ThisTransferTime = GetCountSspClk()) & 0x00000007);
+
+       // Clear TXRDY:
+       AT91C_BASE_SSC->SSC_THR = SEC_F;
+
        // send cycle
-       for(;;) {
-               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                       volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-                       (void)b;
-               }
+       for(; i <= respLen; ) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                       if(i > respLen) {
-                               b = 0xff; // was 0x00
-                               u++;
-                       } else {
-                               b = resp[i];
-                               i++;
-                       }
-                       AT91C_BASE_SSC->SSC_THR = b;
-
-                       if(u > 4) break;
+                       AT91C_BASE_SSC->SSC_THR = resp[i++];
+                       FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
                }
+       
                if(BUTTON_PRESS()) {
                        break;
                }
        }
 
+       // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
+       for (i = 0; i < 2 ; ) {
+               if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+                       AT91C_BASE_SSC->SSC_THR = SEC_F;
+                       FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+                       i++;
+               }
+       }
+       
+       LastTimeProxToAirStart = ThisTransferTime + (correctionNeeded?8:0);
+
        return 0;
 }
 
-int EmSend4bitEx(uint8_t resp, int correctionNeeded){
-  Code4bitAnswerAsTag(resp);
+int EmSend4bitEx(uint8_t resp, bool correctionNeeded){
+       Code4bitAnswerAsTag(resp);
        int res = EmSendCmd14443aRaw(ToSend, ToSendMax, correctionNeeded);
-  if (tracing) LogTrace(&resp, 1, GetDeltaCountUS(), GetParity(&resp, 1), FALSE);
+       // do the tracing for the previous reader request and this tag answer:
+       EmLogTrace(Uart.output, 
+                               Uart.len, 
+                               Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, 
+                               Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 
+                               Uart.parityBits,
+                               &resp, 
+                               1, 
+                               LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
+                               (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG, 
+                               SwapBits(GetParity(&resp, 1), 1));
        return res;
 }
 
 int EmSend4bit(uint8_t resp){
-       return EmSend4bitEx(resp, 0);
+       return EmSend4bitEx(resp, false);
 }
 
-int EmSendCmdExPar(uint8_t *resp, int respLen, int correctionNeeded, uint32_t par){
-  CodeIso14443aAsTagPar(resp, respLen, par);
+int EmSendCmdExPar(uint8_t *resp, int respLen, bool correctionNeeded, uint32_t par){
+       CodeIso14443aAsTagPar(resp, respLen, par);
        int res = EmSendCmd14443aRaw(ToSend, ToSendMax, correctionNeeded);
-  if (tracing) LogTrace(resp, respLen, GetDeltaCountUS(), par, FALSE);
+       // do the tracing for the previous reader request and this tag answer:
+       EmLogTrace(Uart.output, 
+                               Uart.len, 
+                               Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, 
+                               Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 
+                               Uart.parityBits,
+                               resp, 
+                               respLen, 
+                               LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
+                               (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG, 
+                               SwapBits(GetParity(resp, respLen), respLen));
        return res;
 }
 
-int EmSendCmdEx(uint8_t *resp, int respLen, int correctionNeeded){
+int EmSendCmdEx(uint8_t *resp, int respLen, bool correctionNeeded){
        return EmSendCmdExPar(resp, respLen, correctionNeeded, GetParity(resp, respLen));
 }
 
 int EmSendCmd(uint8_t *resp, int respLen){
-       return EmSendCmdExPar(resp, respLen, 0, GetParity(resp, respLen));
+       return EmSendCmdExPar(resp, respLen, false, GetParity(resp, respLen));
 }
 
 int EmSendCmdPar(uint8_t *resp, int respLen, uint32_t par){
-       return EmSendCmdExPar(resp, respLen, 0, par);
+       return EmSendCmdExPar(resp, respLen, false, par);
+}
+
+bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint32_t reader_Parity,
+                                uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint32_t tag_Parity)
+{
+       if (tracing) {
+               // we cannot exactly measure the end and start of a received command from reader. However we know that the delay from
+               // end of the received command to start of the tag's (simulated by us) answer is n*128+20 or n*128+84 resp.
+               // with n >= 9. The start of the tags answer can be measured and therefore the end of the received command be calculated:
+               uint16_t reader_modlen = reader_EndTime - reader_StartTime;
+               uint16_t approx_fdt = tag_StartTime - reader_EndTime;
+               uint16_t exact_fdt = (approx_fdt - 20 + 32)/64 * 64 + 20;
+               reader_EndTime = tag_StartTime - exact_fdt;
+               reader_StartTime = reader_EndTime - reader_modlen;
+               if (!LogTrace(reader_data, reader_len, reader_StartTime, reader_Parity, TRUE)) {
+                       return FALSE;
+               } else if (!LogTrace(NULL, 0, reader_EndTime, 0, TRUE)) {
+                       return FALSE;
+               } else if (!LogTrace(tag_data, tag_len, tag_StartTime, tag_Parity, FALSE)) {
+                       return FALSE;
+               } else {
+                       return (!LogTrace(NULL, 0, tag_EndTime, 0, FALSE));
+               }
+       } else {
+               return TRUE;
+       }
 }
 
 //-----------------------------------------------------------------------------
@@ -1540,9 +1547,9 @@ int EmSendCmdPar(uint8_t *resp, int respLen, uint32_t par){
 //  If a response is captured return TRUE
 //  If it takes too long return FALSE
 //-----------------------------------------------------------------------------
-static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint16_t offset, int maxLen, int *samples)
+static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint16_t offset, int maxLen)
 {
-       int c;
+       uint16_t c;
        
        // Set FPGA mode to "reader listen mode", no modulation (listen
        // only, since we are receiving, not transmitting).
@@ -1551,26 +1558,23 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint16_t offset,
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);
        
        // Now get the answer from the card
+       DemodReset();
        Demod.output = receivedResponse;
-       Demod.len = 0;
-       Demod.state = DEMOD_UNSYNCD;
-
-       uint8_t b;
 
+       // clear RXRDY:
+    uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+       
        c = 0;
        for(;;) {
                WDT_HIT();
 
-               // if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-                       // AT91C_BASE_SSC->SSC_THR = 0x00;  // To make use of exact timing of next command from reader!!
-                       // if (elapsed) (*elapsed)++;
-               // }
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-                       if(c < iso14a_timeout) { c++; } else { return FALSE; }
                        b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-                       if(ManchesterDecoding(b, offset)) {
-                               *samples = Demod.samples;
+                       if(ManchesterDecoding(b, offset, 0)) {
+                               NextTransferTime = MAX(NextTransferTime, Demod.endTime - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/16 + FRAME_DELAY_TIME_PICC_TO_PCD);
                                return TRUE;
+                       } else if(c++ > iso14a_timeout) {
+                               return FALSE; 
                        }
                }
        }
@@ -1579,15 +1583,18 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint16_t offset,
 void ReaderTransmitBitsPar(uint8_t* frame, int bits, uint32_t par, uint32_t *timing)
 {
 
-  CodeIso14443aBitsAsReaderPar(frame,bits,par);
+       CodeIso14443aBitsAsReaderPar(frame,bits,par);
   
-  // Send command to tag
-  TransmitFor14443a(ToSend, ToSendMax, timing);
-  if(trigger)
-       LED_A_ON();
+       // Send command to tag
+       TransmitFor14443a(ToSend, ToSendMax, timing);
+       if(trigger)
+               LED_A_ON();
   
-  // Log reader command in trace buffer
-  if (tracing) LogTrace(frame,nbytes(bits),0,par,TRUE);
+       // Log reader command in trace buffer
+       if (tracing) {
+               LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, par, TRUE);
+               LogTrace(NULL, 0, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, 0, TRUE);
+       }
 }
 
 void ReaderTransmitPar(uint8_t* frame, int len, uint32_t par, uint32_t *timing)
@@ -1609,10 +1616,11 @@ void ReaderTransmit(uint8_t* frame, int len, uint32_t *timing)
 
 int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset)
 {
-       int samples = 0;
-       if (!GetIso14443aAnswerFromTag(receivedAnswer,offset,160,&samples)) return FALSE;
-       if (tracing) LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE);
-       if(samples == 0) return FALSE;
+       if (!GetIso14443aAnswerFromTag(receivedAnswer,offset,160)) return FALSE;
+       if (tracing) {
+               LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.parityBits, FALSE);
+               LogTrace(NULL, 0, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, 0, FALSE);
+       }
        return Demod.len;
 }
 
@@ -1623,11 +1631,12 @@ int ReaderReceive(uint8_t* receivedAnswer)
 
 int ReaderReceivePar(uint8_t *receivedAnswer, uint32_t *parptr)
 {
-       int samples = 0;
-       if (!GetIso14443aAnswerFromTag(receivedAnswer,0,160,&samples)) return FALSE;
-       if (tracing) LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE);
+       if (!GetIso14443aAnswerFromTag(receivedAnswer,0,160)) return FALSE;
+       if (tracing) {
+               LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.parityBits, FALSE);
+               LogTrace(NULL, 0, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, 0, FALSE);
+       }
        *parptr = Demod.parityBits;
-       if(samples == 0) return FALSE;
        return Demod.len;
 }
 
@@ -1649,6 +1658,7 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u
         
   // Broadcast for a card, WUPA (0x52) will force response from all cards in the field
     ReaderTransmitBitsPar(wupa,7,0, NULL);
+       
   // Receive the ATQA
   if(!ReaderReceive(resp)) return 0;
   // Dbprintf("atqa: %02x %02x",resp[0],resp[1]);
@@ -1707,7 +1717,7 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u
                memcpy(uid_resp,resp,4);
        }
        uid_resp_len = 4;
-    //    Dbprintf("uid: %02x %02x %02x %02x",uid_resp[0],uid_resp[1],uid_resp[2],uid_resp[3]);
+       // Dbprintf("uid: %02x %02x %02x %02x",uid_resp[0],uid_resp[1],uid_resp[2],uid_resp[3]);
 
     // calculate crypto UID. Always use last 4 Bytes.
     if(cuid_ptr) {
@@ -1768,25 +1778,28 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u
   return 1;
 }
 
-void iso14443a_setup() {
+void iso14443a_setup(uint8_t fpga_minor_mode) {
        // Set up the synchronous serial port
        FpgaSetupSsc();
-       // Start from off (no field generated)
-       // Signal field is off with the appropriate LED
-//     LED_D_OFF();
-//     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-       // SpinDelay(50);
-
+       // connect Demodulated Signal to ADC:
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
-       // Now give it time to spin up.
        // Signal field is on with the appropriate LED
-       LED_D_ON();
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
-       SpinDelay(7); // iso14443-3 specifies 5ms max.
+       if (fpga_minor_mode == FPGA_HF_ISO14443A_READER_MOD
+               || fpga_minor_mode == FPGA_HF_ISO14443A_READER_LISTEN) {
+               LED_D_ON();
+       } else {
+               LED_D_OFF();
+       }
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | fpga_minor_mode);
 
-       Demod.state = DEMOD_UNSYNCD;
-       iso14a_timeout = 2048; //default
+       // Start the timer
+       StartCountSspClk();
+       
+       DemodReset();
+       UartReset();
+       NextTransferTime = 2*DELAY_ARM2AIR_AS_READER;
+       iso14a_set_timeout(1050); // 10ms default
 }
 
 int iso14_apdu(uint8_t * cmd, size_t cmd_len, void * data) {
@@ -1820,10 +1833,10 @@ int iso14_apdu(uint8_t * cmd, size_t cmd_len, void * data) {
 // Read an ISO 14443a tag. Send out commands and store answers.
 //
 //-----------------------------------------------------------------------------
-void ReaderIso14443a(UsbCommand * c)
+void ReaderIso14443a(UsbCommand *c)
 {
        iso14a_command_t param = c->arg[0];
-       uint8_t * cmd = c->d.asBytes;
+       uint8_t *cmd = c->d.asBytes;
        size_t len = c->arg[1];
        size_t lenbits = c->arg[2];
        uint32_t arg0 = 0;
@@ -1833,14 +1846,14 @@ void ReaderIso14443a(UsbCommand * c)
                iso14a_clear_trace();
        }
 
-       iso14a_set_tracing(true);
+       iso14a_set_tracing(TRUE);
 
        if(param & ISO14A_REQUEST_TRIGGER) {
-               iso14a_set_trigger(1);
+               iso14a_set_trigger(TRUE);
        }
 
        if(param & ISO14A_CONNECT) {
-               iso14443a_setup();
+               iso14443a_setup(FPGA_HF_ISO14443A_READER_LISTEN);
                if(!(param & ISO14A_NO_SELECT)) {
                        iso14a_card_select_t *card = (iso14a_card_select_t*)buf;
                        arg0 = iso14443a_select_card(NULL,card,NULL);
@@ -1852,10 +1865,6 @@ void ReaderIso14443a(UsbCommand * c)
                iso14a_timeout = c->arg[2];
        }
 
-       if(param & ISO14A_SET_TIMEOUT) {
-               iso14a_timeout = c->arg[2];
-       }
-
        if(param & ISO14A_APDU) {
                arg0 = iso14_apdu(cmd, len, buf);
                cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
@@ -1876,7 +1885,7 @@ void ReaderIso14443a(UsbCommand * c)
        }
 
        if(param & ISO14A_REQUEST_TRIGGER) {
-               iso14a_set_trigger(0);
+               iso14a_set_trigger(FALSE);
        }
 
        if(param & ISO14A_NO_DISCONNECT) {
@@ -1926,8 +1935,9 @@ void ReaderMifare(bool first_try)
        static uint8_t mf_nr_ar3;
 
        uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
+
        iso14a_clear_trace();
-       tracing = false;
+       iso14a_set_tracing(TRUE);
 
        byte_t nt_diff = 0;
        byte_t par = 0;
@@ -1952,11 +1962,9 @@ void ReaderMifare(bool first_try)
 
 
        if (first_try) { 
-               StartCountMifare();
                mf_nr_ar3 = 0;
-               iso14443a_setup();
-               while((GetCountMifare() & 0xffff0000) != 0x10000);              // wait for counter to reset and "warm up" 
-               sync_time = GetCountMifare() & 0xfffffff8;
+               iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
+               sync_time = GetCountSspClk() & 0xfffffff8;
                sync_cycles = 65536;                                                                    // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
                nt_attacked = 0;
                nt = 0;
@@ -1974,7 +1982,7 @@ void ReaderMifare(bool first_try)
        LED_B_OFF();
        LED_C_OFF();
        
-
+  
        for(uint16_t i = 0; TRUE; i++) {
                
                WDT_HIT();
@@ -1991,14 +1999,11 @@ void ReaderMifare(bool first_try)
                        continue;
                }
 
-               //keep the card active
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
-
                sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
                catch_up_cycles = 0;
 
                // if we missed the sync time already, advance to the next nonce repeat
-               while(GetCountMifare() > sync_time) {
+               while(GetCountSspClk() > sync_time) {
                        sync_time = (sync_time & 0xfffffff8) + sync_cycles;
                }
 
@@ -2092,9 +2097,6 @@ void ReaderMifare(bool first_try)
                }
        }
 
-       LogTrace((const uint8_t *)&nt, 4, 0, GetParity((const uint8_t *)&nt, 4), TRUE);
-       LogTrace(par_list, 8, 0, GetParity(par_list, 8), TRUE);
-       LogTrace(ks_list, 8, 0, GetParity(ks_list, 8), TRUE);
 
        mf_nr_ar[3] &= 0x1F;
        
@@ -2110,7 +2112,8 @@ void ReaderMifare(bool first_try)
        // Thats it...
        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
        LEDsoff();
-       tracing = TRUE;
+
+       iso14a_set_tracing(FALSE);
 }
 
 /**
@@ -2157,7 +2160,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 
        uint8_t rAUTH_NT[] = {0x01, 0x02, 0x03, 0x04};
        uint8_t rAUTH_AT[] = {0x00, 0x00, 0x00, 0x00};
-
+               
        //Here, we collect UID,NT,AR,NR,UID2,NT2,AR2,NR2
        // This can be used in a reader-only attack.
        // (it can also be retrieved via 'hf 14a list', but hey...
@@ -2165,31 +2168,27 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
        uint8_t ar_nr_collected = 0;
 
        // clear trace
-       iso14a_clear_trace();
-
-       tracing = true;
+    iso14a_clear_trace();
+       iso14a_set_tracing(TRUE);
 
-  // Authenticate response - nonce
+       // Authenticate response - nonce
        uint32_t nonce = bytes_to_num(rAUTH_NT, 4);
-
+       
        //-- Determine the UID
        // Can be set from emulator memory, incoming data
        // and can be 7 or 4 bytes long
-       if(flags & FLAG_4B_UID_IN_DATA)
+       if (flags & FLAG_4B_UID_IN_DATA)
        {
                // 4B uid comes from data-portion of packet
                memcpy(rUIDBCC1,datain,4);
                rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
 
-       }else if(flags & FLAG_7B_UID_IN_DATA)
-       {
+       } else if (flags & FLAG_7B_UID_IN_DATA) {
                // 7B uid comes from data-portion of packet
                memcpy(&rUIDBCC1[1],datain,3);
                memcpy(rUIDBCC2, datain+3, 4);
                _7BUID = true;
-       }
-       else
-       {
+       } else {
                // get UID from emul memory
                emlGetMemBt(receivedCmd, 7, 1);
                _7BUID = !(receivedCmd[0] == 0x00);
@@ -2200,40 +2199,31 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                        emlGetMemBt(rUIDBCC2, 3, 4);
                }
        }
+
        /*
         * Regardless of what method was used to set the UID, set fifth byte and modify
         * the ATQA for 4 or 7-byte UID
         */
-
        rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
-       if(_7BUID)
-       {
+       if (_7BUID) {
                rATQA[0] = 0x44;
                rUIDBCC1[0] = 0x88;
                rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
        }
 
-       // start mkseconds counter
-       StartCountUS();
-
        // We need to listen to the high-frequency, peak-detected path.
-       SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-       FpgaSetupSsc();
+       iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
 
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-       SpinDelay(200);
 
        if (MF_DBGLEVEL >= 1)   {
                if (!_7BUID) {
                        Dbprintf("4B UID: %02x%02x%02x%02x",rUIDBCC1[0] , rUIDBCC1[1] , rUIDBCC1[2] , rUIDBCC1[3]);
-               }else
-               {
+               } else {
                        Dbprintf("7B UID: (%02x)%02x%02x%02x%02x%02x%02x%02x",rUIDBCC1[0] , rUIDBCC1[1] , rUIDBCC1[2] , rUIDBCC1[3],rUIDBCC2[0],rUIDBCC2[1] ,rUIDBCC2[2] , rUIDBCC2[3]);
                }
        }
-       // calibrate mkseconds counter
-       GetDeltaCountUS();
-       bool finished = false;
+
+       bool finished = FALSE;
        while (!BUTTON_PRESS() && !finished) {
                WDT_HIT();
 
@@ -2251,14 +2241,15 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 
                //Now, get data
 
-               res = EmGetCmd(receivedCmd, &len, RECV_CMD_SIZE); // (+ nextCycleTimeout)
+               res = EmGetCmd(receivedCmd, &len);
                if (res == 2) { //Field is off!
                        cardSTATE = MFEMUL_NOFIELD;
                        LEDsoff();
                        continue;
-               }else if(res == 1) break;//return value 1 means button press
-
-
+               } else if (res == 1) {
+                       break;  //return value 1 means button press
+               }
+                       
                // REQ or WUP request in ANY state and WUP in HALTED state
                if (len == 1 && ((receivedCmd[0] == 0x26 && cardSTATE != MFEMUL_HALTED) || receivedCmd[0] == 0x52)) {
                        selTimer = GetTickCount();
@@ -2272,11 +2263,13 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                        cardAUTHKEY = 0xff;
                        continue;
                }
-
+               
                switch (cardSTATE) {
                        case MFEMUL_NOFIELD:
                        case MFEMUL_HALTED:
                        case MFEMUL_IDLE:{
+                               LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                               LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
                                break;
                        }
                        case MFEMUL_SELECT1:{
@@ -2294,12 +2287,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                // select card
                                if (len == 9 && 
                                                (receivedCmd[0] == 0x93 && receivedCmd[1] == 0x70 && memcmp(&receivedCmd[2], rUIDBCC1, 4) == 0)) {
-
-                                       if (!_7BUID) 
-                                               EmSendCmd(rSAK, sizeof(rSAK));
-                                       else
-                                               EmSendCmd(rSAK1, sizeof(rSAK1));
-
+                                       EmSendCmd(_7BUID?rSAK1:rSAK, sizeof(_7BUID?rSAK1:rSAK));
                                        cuid = bytes_to_num(rUIDBCC1, 4);
                                        if (!_7BUID) {
                                                cardSTATE = MFEMUL_WORK;
@@ -2308,16 +2296,16 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                                break;
                                        } else {
                                                cardSTATE = MFEMUL_SELECT2;
-                                               break;
                                        }
                                }
-                               
                                break;
                        }
                        case MFEMUL_AUTH1:{
                                if( len != 8)
                                {
                                        cardSTATE_TO_IDLE();
+                                       LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                       LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
                                        break;
                                }
                                uint32_t ar = bytes_to_num(receivedCmd, 4);
@@ -2342,10 +2330,12 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                // test if auth OK
                                if (cardRr != prng_successor(nonce, 64)){
                                        if (MF_DBGLEVEL >= 2)   Dbprintf("AUTH FAILED. cardRr=%08x, succ=%08x",cardRr, prng_successor(nonce, 64));
-                                       //Shouldn't we respond anything here?
+                                       // Shouldn't we respond anything here?
                                        // Right now, we don't nack or anything, which causes the
                                        // reader to do a WUPA after a while. /Martin
                                        cardSTATE_TO_IDLE();
+                                       LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                       LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
                                        break;
                                }
 
@@ -2360,8 +2350,11 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                break;
                        }
                        case MFEMUL_SELECT2:{
-                               if (!len) break;
-                       
+                               if (!len) { 
+                                       LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                       LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+                                       break;
+                               }
                                if (len == 2 && (receivedCmd[0] == 0x95 && receivedCmd[1] == 0x20)) {
                                        EmSendCmd(rUIDBCC2, sizeof(rUIDBCC2));
                                        break;
@@ -2371,7 +2364,6 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                if (len == 9 && 
                                                (receivedCmd[0] == 0x95 && receivedCmd[1] == 0x70 && memcmp(&receivedCmd[2], rUIDBCC2, 4) == 0)) {
                                        EmSendCmd(rSAK, sizeof(rSAK));
-
                                        cuid = bytes_to_num(rUIDBCC2, 4);
                                        cardSTATE = MFEMUL_WORK;
                                        LED_B_ON();
@@ -2380,22 +2372,30 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                }
                                
                                // i guess there is a command). go into the work state.
-                               if (len != 4) break;
+                               if (len != 4) {
+                                       LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                       LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+                                       break;
+                               }
                                cardSTATE = MFEMUL_WORK;
                                //goto lbWORK;
                                //intentional fall-through to the next case-stmt
                        }
-                       case MFEMUL_WORK:{
-                               if (len == 0) break;
 
+                       case MFEMUL_WORK:{
+                               if (len == 0) {
+                                       LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                       LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+                                       break;
+                               }
+                               
                                bool encrypted_data = (cardAUTHKEY != 0xFF) ;
 
-                               if(encrypted_data)
-                               {
+                               if(encrypted_data) {
                                        // decrypt seqence
                                        mf_crypto1_decrypt(pcs, receivedCmd, len);
                                }
-
+                               
                                if (len == 4 && (receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61)) {
                                        authTimer = GetTickCount();
                                        cardAUTHSC = receivedCmd[1] / 4;  // received block num
@@ -2408,10 +2408,9 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 
                                                crypto1_word(pcs, cuid ^ nonce, 0);//Update crypto state
                                                num_to_bytes(nonce, 4, rAUTH_AT); // Send nonce
-                                       }
-                                       else{ // nested authentication
+                                       } else { // nested authentication
                                                if (MF_DBGLEVEL >= 2) Dbprintf("Reader doing nested authentication for block %d (0x%02x) with key %d",receivedCmd[1] ,receivedCmd[1],cardAUTHKEY );
-                                               ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0);
+                                               ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0); 
                                                num_to_bytes(ans, 4, rAUTH_AT);
                                        }
                                        EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
@@ -2419,7 +2418,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        cardSTATE = MFEMUL_AUTH1;
                                        break;
                                }
-
+                               
                                // rule 13 of 7.5.3. in ISO 14443-4. chaining shall be continued
                                // BUT... ACK --> NACK
                                if (len == 1 && receivedCmd[0] == CARD_ACK) {
@@ -2433,25 +2432,25 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        break;
                                }
                                
-                               if(len != 4) break;
+                               if(len != 4) {
+                                       LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                       LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+                                       break;
+                               }
 
                                if(receivedCmd[0] == 0x30 // read block
                                                || receivedCmd[0] == 0xA0 // write block
                                                || receivedCmd[0] == 0xC0
                                                || receivedCmd[0] == 0xC1
                                                || receivedCmd[0] == 0xC2 // inc dec restore
-                                               || receivedCmd[0] == 0xB0) // transfer
-                               {
-                                       if (receivedCmd[1] >= 16 * 4)
-                                       {
-
+                                               || receivedCmd[0] == 0xB0) { // transfer
+                                       if (receivedCmd[1] >= 16 * 4) {
                                                EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
                                                if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
                                                break;
                                        }
 
-                                       if (receivedCmd[1] / 4 != cardAUTHSC)
-                                       {
+                                       if (receivedCmd[1] / 4 != cardAUTHSC) {
                                                EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
                                                if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
                                                break;
@@ -2467,8 +2466,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        mf_crypto1_encrypt(pcs, response, 18, &par);
                                        EmSendCmdPar(response, 18, par);
                                        numReads++;
-                                       if(exitAfterNReads > 0 && numReads == exitAfterNReads)
-                                       {
+                                       if(exitAfterNReads > 0 && numReads == exitAfterNReads) {
                                                Dbprintf("%d reads done, exiting", numReads);
                                                finished = true;
                                        }
@@ -2477,17 +2475,14 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                // write block
                                if (receivedCmd[0] == 0xA0) {
                                        if (MF_DBGLEVEL >= 2) Dbprintf("RECV 0xA0 write block %d (%02x)",receivedCmd[1],receivedCmd[1]);
-
                                        EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
-                                       //nextCycleTimeout = 50;
                                        cardSTATE = MFEMUL_WRITEBL2;
                                        cardWRBL = receivedCmd[1];
                                        break;
-                               }                               
+                               }
                                // increment, decrement, restore
                                if (receivedCmd[0] == 0xC0 || receivedCmd[0] == 0xC1 || receivedCmd[0] == 0xC2) {
                                        if (MF_DBGLEVEL >= 2) Dbprintf("RECV 0x%02x inc(0xC1)/dec(0xC0)/restore(0xC2) block %d (%02x)",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
-
                                        if (emlCheckValBl(receivedCmd[1])) {
                                                if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate on block, but emlCheckValBl failed, nacking");
                                                EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
@@ -2501,28 +2496,25 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        if (receivedCmd[0] == 0xC2)
                                                cardSTATE = MFEMUL_INTREG_REST;
                                        cardWRBL = receivedCmd[1];
-
                                        break;
                                }
-                               
                                // transfer
                                if (receivedCmd[0] == 0xB0) {
                                        if (MF_DBGLEVEL >= 2) Dbprintf("RECV 0x%02x transfer block %d (%02x)",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
-                                       
                                        if (emlSetValBl(cardINTREG, cardINTBLOCK, receivedCmd[1]))
                                                EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
                                        else
                                                EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
-                                               
                                        break;
                                }
-
                                // halt
                                if (receivedCmd[0] == 0x50 && receivedCmd[1] == 0x00) {
                                        LED_B_OFF();
                                        LED_C_OFF();
                                        cardSTATE = MFEMUL_HALTED;
                                        if (MF_DBGLEVEL >= 4)   Dbprintf("--> HALTED. Selected time: %d ms",  GetTickCount() - selTimer);
+                                       LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                       LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
                                        break;
                                }
                                // RATS
@@ -2530,12 +2522,9 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
                                        break;
                                }
-
                                // command not allowed
                                if (MF_DBGLEVEL >= 4)   Dbprintf("Received command not allowed, nacking");
                                EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
-
-                               // case break
                                break;
                        }
                        case MFEMUL_WRITEBL2:{
@@ -2544,10 +2533,10 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        emlSetMem(receivedCmd, cardWRBL, 1);
                                        EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
                                        cardSTATE = MFEMUL_WORK;
-                                       break;
                                } else {
                                        cardSTATE_TO_IDLE();
-                                       break;
+                                       LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                                       LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
                                }
                                break;
                        }
@@ -2559,7 +2548,9 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
                                        cardSTATE_TO_IDLE();
                                        break;
-                               }
+                               } 
+                               LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                               LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
                                cardINTREG = cardINTREG + ans;
                                cardSTATE = MFEMUL_WORK;
                                break;
@@ -2572,6 +2563,8 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        cardSTATE_TO_IDLE();
                                        break;
                                }
+                               LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                               LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
                                cardINTREG = cardINTREG - ans;
                                cardSTATE = MFEMUL_WORK;
                                break;
@@ -2584,6 +2577,8 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        cardSTATE_TO_IDLE();
                                        break;
                                }
+                               LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+                               LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
                                cardSTATE = MFEMUL_WORK;
                                break;
                        }
@@ -2593,9 +2588,6 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
        LEDsoff();
 
-       // add trace trailer
-       memset(rAUTH_NT, 0x44, 4);
-       LogTrace(rAUTH_NT, 4, 0, 0, TRUE);
        if(flags & FLAG_INTERACTIVE)// Interactive mode flag, means we need to send ACK
        {
                //May just aswell send the collected ar_nr in the response aswell
@@ -2603,8 +2595,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
        }
        if(flags & FLAG_NR_AR_ATTACK)
        {
-               if(ar_nr_collected > 1)
-               {
+               if(ar_nr_collected > 1) {
                        Dbprintf("Collected two pairs of AR/NR which can be used to extract keys from reader:");
                        Dbprintf("../tools/mfkey/mfkey32 %08x %08x %08x %08x",
                                         ar_nr_responses[0], // UID
@@ -2614,11 +2605,9 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
                                        ar_nr_responses[6], //AR2
                                        ar_nr_responses[7] //NR2
                                        );
-               }else
-               {
+               } else {
                        Dbprintf("Failed to obtain two AR/NR pairs!");
-                       if(ar_nr_collected >0)
-                       {
+                       if(ar_nr_collected >0) {
                                Dbprintf("Only got these: UID=%08d, nonce=%08d, AR1=%08d, NR1=%08d",
                                                ar_nr_responses[0], // UID
                                                ar_nr_responses[1], //NT
@@ -2659,71 +2648,73 @@ void RAMFUNC SniffMifare(uint8_t param) {
        //uint8_t *trace = (uint8_t *)BigBuf;
        
        // The DMA buffer, used to stream samples from the FPGA
-       int8_t *dmaBuf = ((int8_t *)BigBuf) + DMA_BUFFER_OFFSET;
-       int8_t *data = dmaBuf;
+       uint8_t *dmaBuf = ((uint8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+       uint8_t *data = dmaBuf;
+       uint8_t previous_data = 0;
        int maxDataLen = 0;
        int dataLen = 0;
+       bool ReaderIsActive = FALSE;
+       bool TagIsActive = FALSE;
+
+       iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
 
        // Set up the demodulator for tag -> reader responses.
        Demod.output = receivedResponse;
-       Demod.len = 0;
-       Demod.state = DEMOD_UNSYNCD;
 
        // Set up the demodulator for the reader -> tag commands
-       memset(&Uart, 0, sizeof(Uart));
        Uart.output = receivedCmd;
-       Uart.byteCntMax = 32; // was 100 (greg)//////////////////
-       Uart.state = STATE_UNSYNCD;
 
        // Setup for the DMA.
-       FpgaSetupSsc();
-       FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
+       FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
 
-       // And put the FPGA in the appropriate mode
-       // Signal field is off with the appropriate LED
        LED_D_OFF();
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_SNIFFER);
-       SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
        
        // init sniffer
        MfSniffInit();
-       int sniffCounter = 0;
 
        // And now we loop, receiving samples.
-       while(true) {
+       for(uint32_t sniffCounter = 0; TRUE; ) {
+       
                if(BUTTON_PRESS()) {
                        DbpString("cancelled by button");
-                       goto done;
+                       break;
                }
 
                LED_A_ON();
                WDT_HIT();
                
-               if (++sniffCounter > 65) {
-                       if (MfSniffSend(2000)) {
-                               FpgaEnableSscDma();
+               if ((sniffCounter & 0x0000FFFF) == 0) { // from time to time
+                       // check if a transaction is completed (timeout after 2000ms).
+                       // if yes, stop the DMA transfer and send what we have so far to the client
+                       if (MfSniffSend(2000)) {                        
+                               // Reset everything - we missed some sniffed data anyway while the DMA was stopped
+                               sniffCounter = 0;
+                               data = dmaBuf;
+                               maxDataLen = 0;
+                               ReaderIsActive = FALSE;
+                               TagIsActive = FALSE;
+                               FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
                        }
-                       sniffCounter = 0;
                }
-
-               int register readBufDataP = data - dmaBuf;
-               int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR;
-               if (readBufDataP <= dmaBufDataP){
-                       dataLen = dmaBufDataP - readBufDataP;
-               } else {
-                       dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP + 1;
+               
+               int register readBufDataP = data - dmaBuf;      // number of bytes we have processed so far
+               int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR; // number of bytes already transferred
+               if (readBufDataP <= dmaBufDataP){                       // we are processing the same block of data which is currently being transferred
+                       dataLen = dmaBufDataP - readBufDataP;   // number of bytes still to be processed
+               } else {                                                                        
+                       dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP; // number of bytes still to be processed
                }
                // test for length of buffer
-               if(dataLen > maxDataLen) {
-                       maxDataLen = dataLen;
+               if(dataLen > maxDataLen) {                                      // we are more behind than ever...
+                       maxDataLen = dataLen;                                   
                        if(dataLen > 400) {
                                Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
-                               goto done;
+                               break;
                        }
                }
                if(dataLen < 1) continue;
 
-               // primary buffer was stopped( <-- we lost data!
+               // primary buffer was stopped ( <-- we lost data!
                if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
                        AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
                        AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
@@ -2737,44 +2728,51 @@ void RAMFUNC SniffMifare(uint8_t param) {
 
                LED_A_OFF();
                
-               if(MillerDecoding((data[0] & 0xF0) >> 4)) {
-                       LED_C_INV();
-                       // check - if there is a short 7bit request from reader
-                       if (MfSniffLogic(receivedCmd, Uart.byteCnt, Uart.parityBits, Uart.bitCnt, TRUE)) break;
-
-                       /* And ready to receive another command. */
-                       Uart.state = STATE_UNSYNCD;
-                       
-                       /* And also reset the demod code */
-                       Demod.state = DEMOD_UNSYNCD;
-               }
+               if (sniffCounter & 0x01) {
 
-               if(ManchesterDecoding(data[0], 0)) {
-                       LED_C_INV();
+                       if(!TagIsActive) {              // no need to try decoding tag data if the reader is sending
+                               uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
+                               if(MillerDecoding(readerdata, (sniffCounter-1)*4)) {
+                                       LED_C_INV();
+                                       if (MfSniffLogic(receivedCmd, Uart.len, Uart.parityBits, Uart.bitCount, TRUE)) break;
 
-                       if (MfSniffLogic(receivedResponse, Demod.len, Demod.parityBits, Demod.bitCount, FALSE)) break;
+                                       /* And ready to receive another command. */
+                                       UartReset();
+                                       
+                                       /* And also reset the demod code */
+                                       DemodReset();
+                               }
+                               ReaderIsActive = (Uart.state != STATE_UNSYNCD);
+                       }
+                       
+                       if(!ReaderIsActive) {           // no need to try decoding tag data if the reader is sending
+                               uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
+                               if(ManchesterDecoding(tagdata, 0, (sniffCounter-1)*4)) {
+                                       LED_C_INV();
 
-                       // And ready to receive another response.
-                       memset(&Demod, 0, sizeof(Demod));
-                       Demod.output = receivedResponse;
-                       Demod.state = DEMOD_UNSYNCD;
+                                       if (MfSniffLogic(receivedResponse, Demod.len, Demod.parityBits, Demod.bitCount, FALSE)) break;
 
-                       /* And also reset the uart code */
-                       Uart.state = STATE_UNSYNCD;
+                                       // And ready to receive another response.
+                                       DemodReset();
+                               }
+                               TagIsActive = (Demod.state != DEMOD_UNSYNCD);
+                       }
                }
 
+               previous_data = *data;
+               sniffCounter++;
                data++;
                if(data > dmaBuf + DMA_BUFFER_SIZE) {
                        data = dmaBuf;
                }
+
        } // main cycle
 
        DbpString("COMMAND FINISHED");
 
-done:
        FpgaDisableSscDma();
        MfSniffEnd();
        
-       Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.byteCnt=%x Uart.byteCntMax=%x", maxDataLen, Uart.state, Uart.byteCnt, Uart.byteCntMax);
+       Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.len=%x", maxDataLen, Uart.state, Uart.len);
        LEDsoff();
 }
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