X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/61972abbdd0a03832cae7d5ae58548fed11e619e..5ff3c4017bdbfe78238ef48c3b521e79819ed359:/armsrc/lfops.c

diff --git a/armsrc/lfops.c b/armsrc/lfops.c
index e34eab35..70c6e33b 100644
--- a/armsrc/lfops.c
+++ b/armsrc/lfops.c
@@ -37,15 +37,15 @@ void ModThenAcquireRawAdcSamples125k(int delay_off, int period_0, int period_1,
 	sample_config sc = { 0,0,1, divisor_used, 0};
 	setSamplingConfig(&sc);
 
-	/* Make sure the tag is reset */
-	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	SpinDelay(2500);
+    /* Make sure the tag is reset */
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+    SpinDelay(2500);
 
 	LFSetupFPGAForADC(sc.divisor, 1);
 
-	// And a little more time for the tag to fully power up
-	SpinDelay(2000);
+    // And a little more time for the tag to fully power up
+    SpinDelay(2000);
 
     // now modulate the reader field
     while(*command != '\0' && *command != ' ') {
@@ -72,8 +72,6 @@ void ModThenAcquireRawAdcSamples125k(int delay_off, int period_0, int period_1,
 	DoAcquisition_config(false);
 }
 
-
-
 /* blank r/w tag data stream
 ...0000000000000000 01111111
 1010101010101010101010101010101010101010101010101010101010101010
@@ -381,7 +379,7 @@ void WriteTItag(uint32_t idhi, uint32_t idlo, uint16_t crc)
     DbpString("Now use tiread to check");
 }
 
-void SimulateTagLowFrequency(int period, int gap, int ledcontrol)
+void SimulateTagLowFrequency(uint16_t period, uint32_t gap, uint8_t ledcontrol)
 {
     int i;
     uint8_t *tab = BigBuf_get_addr();
@@ -394,11 +392,12 @@ void SimulateTagLowFrequency(int period, int gap, int ledcontrol)
     AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
     AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_CLK;
 
-#define SHORT_COIL()	LOW(GPIO_SSC_DOUT)
-#define OPEN_COIL()		HIGH(GPIO_SSC_DOUT)
+ #define SHORT_COIL()	LOW(GPIO_SSC_DOUT)
+ #define OPEN_COIL()		HIGH(GPIO_SSC_DOUT)
 
     i = 0;
     for(;;) {
+        //wait until SSC_CLK goes HIGH
         while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)) {
             if(BUTTON_PRESS()) {
                 DbpString("Stopped");
@@ -406,7 +405,6 @@ void SimulateTagLowFrequency(int period, int gap, int ledcontrol)
             }
             WDT_HIT();
         }
-
         if (ledcontrol)
             LED_D_ON();
 
@@ -417,17 +415,18 @@ void SimulateTagLowFrequency(int period, int gap, int ledcontrol)
 
         if (ledcontrol)
             LED_D_OFF();
-
+        //wait until SSC_CLK goes LOW
         while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK) {
             if(BUTTON_PRESS()) {
                 DbpString("Stopped");
                 return;
             }
             WDT_HIT();
-        }
-
+        }    
+               
         i++;
         if(i == period) {
+      
             i = 0;
             if (gap) {
                 SHORT_COIL();
@@ -442,8 +441,9 @@ void SimulateTagLowFrequencyBidir(int divisor, int t0)
 {
 }
 
-// compose fc/8 fc/10 waveform
-static void fc(int c, int *n) {
+// compose fc/8 fc/10 waveform (FSK2)
+static void fc(int c, int *n)
+{
     uint8_t *dest = BigBuf_get_addr();
     int idx;
 
@@ -451,20 +451,21 @@ static void fc(int c, int *n) {
     if(c==0) {
         dest[((*n)++)]=1;
         dest[((*n)++)]=1;
-        dest[((*n)++)]=0;
-        dest[((*n)++)]=0;
+        dest[((*n)++)]=1;
+        dest[((*n)++)]=1;
         dest[((*n)++)]=0;
         dest[((*n)++)]=0;
         dest[((*n)++)]=0;
         dest[((*n)++)]=0;
     }
-    //	an fc/8  encoded bit is a bit pattern of  11000000  x6 = 48 samples
+  
+    //	an fc/8  encoded bit is a bit pattern of  11110000  x6 = 48 samples
     if(c==8) {
         for (idx=0; idx<6; idx++) {
             dest[((*n)++)]=1;
             dest[((*n)++)]=1;
-            dest[((*n)++)]=0;
-            dest[((*n)++)]=0;
+            dest[((*n)++)]=1;
+            dest[((*n)++)]=1;
             dest[((*n)++)]=0;
             dest[((*n)++)]=0;
             dest[((*n)++)]=0;
@@ -472,14 +473,14 @@ static void fc(int c, int *n) {
         }
     }
 
-    //	an fc/10 encoded bit is a bit pattern of 1110000000 x5 = 50 samples
+    //	an fc/10 encoded bit is a bit pattern of 1111100000 x5 = 50 samples
     if(c==10) {
         for (idx=0; idx<5; idx++) {
             dest[((*n)++)]=1;
             dest[((*n)++)]=1;
             dest[((*n)++)]=1;
-            dest[((*n)++)]=0;
-            dest[((*n)++)]=0;
+            dest[((*n)++)]=1;
+            dest[((*n)++)]=1;
             dest[((*n)++)]=0;
             dest[((*n)++)]=0;
             dest[((*n)++)]=0;
@@ -488,6 +489,36 @@ static void fc(int c, int *n) {
         }
     }
 }
+// compose fc/X fc/Y waveform (FSKx)
+static void fcAll(uint8_t fc, int *n, uint8_t clock, uint16_t *modCnt) 
+{
+    uint8_t *dest = BigBuf_get_addr();
+    uint8_t halfFC = fc/2;
+    uint8_t wavesPerClock = clock/fc;
+    uint8_t mod = clock % fc;    //modifier
+    uint8_t modAdj = fc/mod;     //how often to apply modifier
+    bool modAdjOk = !(fc % mod); //if (fc % mod==0) modAdjOk=TRUE;
+    // loop through clock - step field clock
+    for (uint8_t idx=0; idx < wavesPerClock; idx++){
+        // put 1/2 FC length 1's and 1/2 0's per field clock wave (to create the wave)
+        memset(dest+(*n), 0, fc-halfFC);  //in case of odd number use extra here
+        memset(dest+(*n)+(fc-halfFC), 1, halfFC);
+        *n += fc;
+    }
+    if (mod>0) (*modCnt)++;
+    if ((mod>0) && modAdjOk){  //fsk2 
+        if ((*modCnt % modAdj) == 0){ //if 4th 8 length wave in a rf/50 add extra 8 length wave
+            memset(dest+(*n), 0, fc-halfFC);
+            memset(dest+(*n)+(fc-halfFC), 1, halfFC);
+            *n += fc;
+        }
+    }
+    if (mod>0 && !modAdjOk){  //fsk1
+        memset(dest+(*n), 0, mod-(mod/2));
+        memset(dest+(*n)+(mod-(mod/2)), 1, mod/2);
+        *n += mod;
+    }
+}
 
 // prepare a waveform pattern in the buffer based on the ID given then
 // simulate a HID tag until the button is pressed
@@ -505,7 +536,7 @@ void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
     */
 
     if (hi>0xFFF) {
-        DbpString("Tags can only have 44 bits.");
+        DbpString("Tags can only have 44 bits. - USE lf simfsk for larger tags");
         return;
     }
     fc(0,&n);
@@ -545,6 +576,150 @@ void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
         LED_A_OFF();
 }
 
+// prepare a waveform pattern in the buffer based on the ID given then
+// simulate a FSK tag until the button is pressed
+// arg1 contains fcHigh and fcLow, arg2 contains invert and clock
+void CmdFSKsimTAG(uint16_t arg1, uint16_t arg2, size_t size, uint8_t *BitStream)
+{
+    int ledcontrol=1;
+    int n=0, i=0;
+    uint8_t fcHigh = arg1 >> 8;
+    uint8_t fcLow = arg1 & 0xFF;
+    uint16_t modCnt = 0;
+    uint8_t clk = arg2 & 0xFF;
+    uint8_t invert = (arg2 >> 8) & 1;
+
+    for (i=0; i<size; i++){
+        if (BitStream[i] == invert){
+            fcAll(fcLow, &n, clk, &modCnt);
+        } else {
+            fcAll(fcHigh, &n, clk, &modCnt);
+        }
+    }
+    Dbprintf("Simulating with fcHigh: %d, fcLow: %d, clk: %d, invert: %d, n: %d",fcHigh, fcLow, clk, invert, n);
+    /*Dbprintf("DEBUG: First 32:");
+    uint8_t *dest = BigBuf_get_addr();
+    i=0;
+    Dbprintf("%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d", dest[i],dest[i+1],dest[i+2],dest[i+3],dest[i+4],dest[i+5],dest[i+6],dest[i+7],dest[i+8],dest[i+9],dest[i+10],dest[i+11],dest[i+12],dest[i+13],dest[i+14],dest[i+15]);
+    i+=16;
+    Dbprintf("%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d", dest[i],dest[i+1],dest[i+2],dest[i+3],dest[i+4],dest[i+5],dest[i+6],dest[i+7],dest[i+8],dest[i+9],dest[i+10],dest[i+11],dest[i+12],dest[i+13],dest[i+14],dest[i+15]);
+    */     
+    if (ledcontrol)
+        LED_A_ON();
+
+    SimulateTagLowFrequency(n, 0, ledcontrol);
+
+    if (ledcontrol)
+        LED_A_OFF();
+}
+
+// compose ask waveform for one bit(ASK)
+static void askSimBit(uint8_t c, int *n, uint8_t clock, uint8_t manchester) 
+{
+    uint8_t *dest = BigBuf_get_addr();
+    uint8_t halfClk = clock/2;
+    // c = current bit 1 or 0
+    if (manchester){
+        memset(dest+(*n), c, halfClk);
+        memset(dest+(*n) + halfClk, c^1, halfClk);
+    } else {
+        memset(dest+(*n), c, clock);
+    }
+    *n += clock;        
+}
+
+// args clock, ask/man or askraw, invert, transmission separator
+void CmdASKsimTag(uint16_t arg1, uint16_t arg2, size_t size, uint8_t *BitStream)
+{
+    int ledcontrol = 1;
+    int n=0, i=0;
+    uint8_t clk = (arg1 >> 8) & 0xFF;
+    uint8_t manchester = arg1 & 1;
+    uint8_t separator = arg2 & 1;
+    uint8_t invert = (arg2 >> 8) & 1;
+    for (i=0; i<size; i++){
+        askSimBit(BitStream[i]^invert, &n, clk, manchester);
+    }
+    if (manchester==0 && BitStream[0]==BitStream[size-1]){ //run a second set inverted (for biphase phase)
+        for (i=0; i<size; i++){
+            askSimBit(BitStream[i]^invert^1, &n, clk, manchester);
+        }    
+    }
+    if (separator==1) Dbprintf("sorry but separator option not yet available"); 
+
+    Dbprintf("Simulating with clk: %d, invert: %d, manchester: %d, separator: %d, n: %d",clk, invert, manchester, separator, n);
+    //DEBUG
+    //Dbprintf("First 32:");
+    //uint8_t *dest = BigBuf_get_addr();
+    //i=0;
+    //Dbprintf("%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d", dest[i],dest[i+1],dest[i+2],dest[i+3],dest[i+4],dest[i+5],dest[i+6],dest[i+7],dest[i+8],dest[i+9],dest[i+10],dest[i+11],dest[i+12],dest[i+13],dest[i+14],dest[i+15]);
+    //i+=16;
+    //Dbprintf("%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d", dest[i],dest[i+1],dest[i+2],dest[i+3],dest[i+4],dest[i+5],dest[i+6],dest[i+7],dest[i+8],dest[i+9],dest[i+10],dest[i+11],dest[i+12],dest[i+13],dest[i+14],dest[i+15]);
+
+    if (ledcontrol)
+        LED_A_ON();
+    
+    SimulateTagLowFrequency(n, 0, ledcontrol);
+
+    if (ledcontrol)
+        LED_A_OFF();
+}
+
+//carrier can be 2,4 or 8
+static void pskSimBit(uint8_t waveLen, int *n, uint8_t clk, uint8_t *curPhase, bool phaseChg)
+{
+    uint8_t *dest = BigBuf_get_addr();
+    uint8_t halfWave = waveLen/2;
+    //uint8_t idx;
+    int i = 0;
+    if (phaseChg){
+        // write phase change
+        memset(dest+(*n), *curPhase^1, halfWave);
+        memset(dest+(*n) + halfWave, *curPhase, halfWave);
+        *n += waveLen;
+        *curPhase ^= 1;
+        i += waveLen;
+    }
+    //write each normal clock wave for the clock duration
+    for (; i < clk; i+=waveLen){
+        memset(dest+(*n), *curPhase, halfWave);
+        memset(dest+(*n) + halfWave, *curPhase^1, halfWave);
+        *n += waveLen;
+    }
+}
+
+// args clock, carrier, invert,
+void CmdPSKsimTag(uint16_t arg1, uint16_t arg2, size_t size, uint8_t *BitStream)
+{
+    int ledcontrol=1;
+    int n=0, i=0;
+    uint8_t clk = arg1 >> 8;
+    uint8_t carrier = arg1 & 0xFF;
+    uint8_t invert = arg2 & 0xFF;
+    uint8_t curPhase = 0;
+    for (i=0; i<size; i++){
+        if (BitStream[i] == curPhase){
+            pskSimBit(carrier, &n, clk, &curPhase, FALSE);
+        } else {
+            pskSimBit(carrier, &n, clk, &curPhase, TRUE);
+        }            
+    }
+    Dbprintf("Simulating with Carrier: %d, clk: %d, invert: %d, n: %d",carrier, clk, invert, n);
+    //Dbprintf("DEBUG: First 32:");
+    //uint8_t *dest = BigBuf_get_addr();
+    //i=0;
+    //Dbprintf("%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d", dest[i],dest[i+1],dest[i+2],dest[i+3],dest[i+4],dest[i+5],dest[i+6],dest[i+7],dest[i+8],dest[i+9],dest[i+10],dest[i+11],dest[i+12],dest[i+13],dest[i+14],dest[i+15]);
+    //i+=16;
+    //Dbprintf("%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d", dest[i],dest[i+1],dest[i+2],dest[i+3],dest[i+4],dest[i+5],dest[i+6],dest[i+7],dest[i+8],dest[i+9],dest[i+10],dest[i+11],dest[i+12],dest[i+13],dest[i+14],dest[i+15]);
+           
+    if (ledcontrol)
+        LED_A_ON();
+    SimulateTagLowFrequency(n, 0, ledcontrol);
+
+    if (ledcontrol)
+        LED_A_OFF();
+}
+
 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
 void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
 {
@@ -562,7 +737,7 @@ void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
         if (ledcontrol) LED_A_ON();
 
 		DoAcquisition_default(-1,true);
-		// FSK demodulator
+        // FSK demodulator
         size = sizeOfBigBuff;  //variable size will change after demod so re initialize it before use
 		idx = HIDdemodFSK(dest, &size, &hi2, &hi, &lo);
         
@@ -651,7 +826,7 @@ void CmdEM410xdemod(int findone, int *high, int *low, int ledcontrol)
         if (ledcontrol) LED_A_ON();
 
 		DoAcquisition_default(-1,true);
-		size  = BigBuf_max_traceLen();
+        size  = BigBuf_max_traceLen();
         //Dbprintf("DEBUG: Buffer got");
 		//askdemod and manchester decode
 		errCnt = askmandemod(dest, &size, &clk, &invert, maxErr);
@@ -704,7 +879,7 @@ void CmdIOdemodFSK(int findone, int *high, int *low, int ledcontrol)
         WDT_HIT();
         if (ledcontrol) LED_A_ON();
 		DoAcquisition_default(-1,true);
-		//fskdemod and get start index
+        //fskdemod and get start index
         WDT_HIT();
         idx = IOdemodFSK(dest, BigBuf_max_traceLen());
         if (idx>0){
@@ -813,10 +988,20 @@ void CmdIOdemodFSK(int findone, int *high, int *low, int ledcontrol)
  * To compensate antenna falling times shorten the write times
  * and enlarge the gap ones.
  */
-#define START_GAP 250
-#define WRITE_GAP 160
-#define WRITE_0   144 // 192
-#define WRITE_1   400 // 432 for T55x7; 448 for E5550
+#define START_GAP 30*8 // 10 - 50fc 250
+#define WRITE_GAP 20*8 //  8 - 30fc
+#define WRITE_0   24*8 // 16 - 31fc 24fc 192
+#define WRITE_1   54*8 // 48 - 63fc 54fc 432 for T55x7; 448 for E5550
+
+//  VALUES TAKEN FROM EM4x function: SendForward
+//  START_GAP = 440;       (55*8) cycles at 125Khz (8us = 1cycle)
+//  WRITE_GAP = 128;       (16*8)
+//  WRITE_1   = 256 32*8;  (32*8) 
+
+//  These timings work for 4469/4269/4305 (with the 55*8 above)
+//  WRITE_0 = 23*8 , 9*8  SpinDelayUs(23*8); 
+
+#define T55xx_SAMPLES_SIZE		12000 // 32 x 32 x 10  (32 bit times numofblock (7), times clock skip..)
 
 // Write one bit to card
 void T55xxWriteBit(int bit)
@@ -824,7 +1009,7 @@ void T55xxWriteBit(int bit)
     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
-    if (bit == 0)
+	if (!bit)
         SpinDelayUs(WRITE_0);
     else
         SpinDelayUs(WRITE_1);
@@ -835,16 +1020,11 @@ void T55xxWriteBit(int bit)
 // Write one card block in page 0, no lock
 void T55xxWriteBlock(uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t PwdMode)
 {
-    //unsigned int i;  //enio adjustment 12/10/14
-    uint32_t i;
+	uint32_t i = 0;
 
-    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
-    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
-
-    // Give it a bit of time for the resonant antenna to settle.
-    // And for the tag to fully power up
-    SpinDelay(150);
+	// Set up FPGA, 125kHz
+	// Wait for config.. (192+8190xPOW)x8 == 67ms
+	LFSetupFPGAForADC(0, true);
 
     // Now start writting
     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
@@ -880,27 +1060,17 @@ void T55xxWriteBlock(uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t PwdMod
 // Read one card block in page 0
 void T55xxReadBlock(uint32_t Block, uint32_t Pwd, uint8_t PwdMode)
 {
+    uint32_t i = 0;
     uint8_t *dest = BigBuf_get_addr();
-    //int m=0, i=0; //enio adjustment 12/10/14
-    uint32_t m=0, i=0;
-    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
-    m = BigBuf_max_traceLen();
-    // Clear destination buffer before sending the command
-    memset(dest, 128, m);
-    // Connect the A/D to the peak-detected low-frequency path.
-    SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
-    // Now set up the SSC to get the ADC samples that are now streaming at us.
-    FpgaSetupSsc();
-
-    LED_D_ON();
-    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
-
-    // Give it a bit of time for the resonant antenna to settle.
-    // And for the tag to fully power up
-    SpinDelay(150);
-
-    // Now start writting
+    uint16_t bufferlength = BigBuf_max_traceLen();
+	if ( bufferlength > T55xx_SAMPLES_SIZE )
+		bufferlength = T55xx_SAMPLES_SIZE;
+
+	memset(dest, 0x80, bufferlength);
+	
+	// Set up FPGA, 125kHz
+	// Wait for config.. (192+8190xPOW)x8 == 67ms
+	LFSetupFPGAForADC(0, true);
     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
     SpinDelayUs(START_GAP);
 
@@ -919,53 +1089,40 @@ void T55xxReadBlock(uint32_t Block, uint32_t Pwd, uint8_t PwdMode)
         T55xxWriteBit(Block & i);
 
     // Turn field on to read the response
-    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+	TurnReadLFOn();
 
     // Now do the acquisition
     i = 0;
     for(;;) {
         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
             AT91C_BASE_SSC->SSC_THR = 0x43;
+			LED_D_ON();
         }
         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
             dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-            // we don't care about actual value, only if it's more or less than a
-            // threshold essentially we capture zero crossings for later analysis
-            //			if(dest[i] < 127) dest[i] = 0; else dest[i] = 1;
-            i++;
-            if (i >= m) break;
+			++i;
+			LED_D_OFF();
+			if (i >= bufferlength) break;
         }
     }
 
+	cmd_send(CMD_ACK,0,0,0,0,0);
     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
     LED_D_OFF();
-    DbpString("DONE!");
 }
 
 // Read card traceability data (page 1)
 void T55xxReadTrace(void){
-    uint8_t *dest = BigBuf_get_addr();
-    int m=0, i=0;
-
-    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
-    m = BigBuf_max_traceLen();
-    // Clear destination buffer before sending the command
-    memset(dest, 128, m);
-    // Connect the A/D to the peak-detected low-frequency path.
-    SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
-    // Now set up the SSC to get the ADC samples that are now streaming at us.
-    FpgaSetupSsc();
 
-    LED_D_ON();
-    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
-
-    // Give it a bit of time for the resonant antenna to settle.
-    // And for the tag to fully power up
-    SpinDelay(150);
+	uint32_t i = 0;
+    uint8_t *dest = BigBuf_get_addr();
+    uint16_t bufferlength = BigBuf_max_traceLen();
+	if ( bufferlength > T55xx_SAMPLES_SIZE )
+		bufferlength = T55xx_SAMPLES_SIZE;
 
-    // Now start writting
+	memset(dest, 0x80, bufferlength);  
+  
+	LFSetupFPGAForADC(0, true);
     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
     SpinDelayUs(START_GAP);
 
@@ -974,25 +1131,34 @@ void T55xxReadTrace(void){
     T55xxWriteBit(1); //Page 1
 
     // Turn field on to read the response
-    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+	TurnReadLFOn();
 
     // Now do the acquisition
-    i = 0;
     for(;;) {
         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
             AT91C_BASE_SSC->SSC_THR = 0x43;
+			LED_D_ON();
         }
         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
             dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-            i++;
-            if (i >= m) break;
-        }
-    }
-
+			++i;
+			LED_D_OFF();
+		
+			if (i >= bufferlength) break;
+		}
+	}
+  
+	cmd_send(CMD_ACK,0,0,0,0,0);
     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
     LED_D_OFF();
-    DbpString("DONE!");
+}
+
+void TurnReadLFOn(){
+	//FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+	// Give it a bit of time for the resonant antenna to settle.
+	//SpinDelay(30);
+	SpinDelayUs(9*150);
 }
 
 /*-------------- Cloning routines -----------*/
@@ -1297,9 +1463,10 @@ void CopyIndala224toT55x7(int uid1, int uid2, int uid3, int uid4, int uid5, int
 #define max(x,y) ( x<y ? y:x)
 
 int DemodPCF7931(uint8_t **outBlocks) {
-    uint8_t BitStream[256];
-    uint8_t Blocks[8][16];
-    uint8_t *GraphBuffer = BigBuf_get_addr();
+
+    uint8_t BitStream[256] = {0x00};
+	uint8_t Blocks[8][16];
+    uint8_t *dest = BigBuf_get_addr();
     int GraphTraceLen = BigBuf_max_traceLen();
     int i, j, lastval, bitidx, half_switch;
     int clock = 64;
@@ -1311,8 +1478,7 @@ int DemodPCF7931(uint8_t **outBlocks) {
     uint8_t dir;
 
 	LFSetupFPGAForADC(95, true);
-	DoAcquisition_default(0, 0);
-
+	DoAcquisition_default(0, true);
 
     lmin = 64;
     lmax = 192;
@@ -1320,9 +1486,9 @@ int DemodPCF7931(uint8_t **outBlocks) {
     i = 2;
 
     /* Find first local max/min */
-    if(GraphBuffer[1] > GraphBuffer[0]) {
+    if(dest[1] > dest[0]) {
         while(i < GraphTraceLen) {
-            if( !(GraphBuffer[i] > GraphBuffer[i-1]) && GraphBuffer[i] > lmax)
+            if( !(dest[i] > dest[i-1]) && dest[i] > lmax)
                 break;
             i++;
         }
@@ -1330,7 +1496,7 @@ int DemodPCF7931(uint8_t **outBlocks) {
     }
     else {
         while(i < GraphTraceLen) {
-            if( !(GraphBuffer[i] < GraphBuffer[i-1]) && GraphBuffer[i] < lmin)
+            if( !(dest[i] < dest[i-1]) && dest[i] < lmin)
                 break;
             i++;
         }
@@ -1344,7 +1510,7 @@ int DemodPCF7931(uint8_t **outBlocks) {
 
     for (bitidx = 0; i < GraphTraceLen; i++)
     {
-        if ( (GraphBuffer[i-1] > GraphBuffer[i] && dir == 1 && GraphBuffer[i] > lmax) || (GraphBuffer[i-1] < GraphBuffer[i] && dir == 0 && GraphBuffer[i] < lmin))
+        if ( (dest[i-1] > dest[i] && dir == 1 && dest[i] > lmax) || (dest[i-1] < dest[i] && dir == 0 && dest[i] < lmin))
         {
             lc = i - lastval;
             lastval = i;
@@ -1411,7 +1577,7 @@ int DemodPCF7931(uint8_t **outBlocks) {
             }
             if(i < GraphTraceLen)
             {
-                if (GraphBuffer[i-1] > GraphBuffer[i]) dir=0;
+                if (dest[i-1] > dest[i]) dir=0;
                 else dir = 1;
             }
         }
@@ -1539,7 +1705,7 @@ void ReadPCF7931() {
         tries++;
         if (BUTTON_PRESS()) return;
     } while (num_blocks != max_blocks);
-end:
+ end:
     Dbprintf("-----------------------------------------");
     Dbprintf("Memory content:");
     Dbprintf("-----------------------------------------");
@@ -1718,9 +1884,14 @@ void EM4xLogin(uint32_t Password) {
 
 void EM4xReadWord(uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
 
+  	uint8_t *dest =  BigBuf_get_addr();
+	uint16_t bufferlength = BigBuf_max_traceLen();
+	uint32_t i = 0;
+
+	// Clear destination buffer before sending the command  0x80 = average.
+	memset(dest, 0x80, bufferlength);
+	
     uint8_t fwd_bit_count;
-    uint8_t *dest = BigBuf_get_addr();
-    int m=0, i=0;
 
     //If password mode do login
     if (PwdMode == 1) EM4xLogin(Pwd);
@@ -1729,9 +1900,6 @@ void EM4xReadWord(uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
     fwd_bit_count = Prepare_Cmd( FWD_CMD_READ );
     fwd_bit_count += Prepare_Addr( Address );
 
-    m = BigBuf_max_traceLen();
-    // Clear destination buffer before sending the command
-    memset(dest, 128, m);
     // Connect the A/D to the peak-detected low-frequency path.
     SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
     // Now set up the SSC to get the ADC samples that are now streaming at us.
@@ -1747,10 +1915,12 @@ void EM4xReadWord(uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
         }
         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
             dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-            i++;
-            if (i >= m) break;
-        }
-    }
+			++i;
+			if (i >= bufferlength) break;
+		}
+	}
+  
+	cmd_send(CMD_ACK,0,0,0,0,0);
     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
     LED_D_OFF();
 }