adjust lf t55xx read commands

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index a3a7a50087727fc1f85a7a5a8df881537e21e04e..3b9402cca18ef45f0dca6c788ef2adcad7a02df4 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -369,7 +369,9 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
        if (fclow==0) fclow=8;
        //set the threshold close to 0 (graph) or 128 std to avoid static
        uint8_t threshold_value = 123; 
-
+       size_t preLastSample = 0;
+       size_t LastSample = 0;
+       size_t currSample = 0;
        // sync to first lo-hi transition, and threshold
 
        // Need to threshold first sample
@@ -389,13 +391,22 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow
 
                // Check for 0->1 transition
                if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
-                       if ((idx-last_transition)<(fclow-2)){            //0-5 = garbage noise
+                       preLastSample = LastSample;
+                       LastSample = currSample;
+                       currSample = idx-last_transition;
+                       if (currSample < (fclow-2)){            //0-5 = garbage noise
                                //do nothing with extra garbage
-                       } else if ((idx-last_transition) < (fchigh-1)) { //6-8 = 8 waves
+                       } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves
+                               if (LastSample > (fchigh-2) && preLastSample < (fchigh-1)){
+                                       dest[numBits-1]=1;  //correct last 9 wave surrounded by 8 waves
+                               }
                                dest[numBits++]=1;
-                       } else if ((idx-last_transition) > (fchigh+1) && !numBits) { //12 + and first bit = garbage 
+
+                       } else if (currSample > (fchigh+1) && !numBits) { //12 + and first bit = garbage 
                                //do nothing with beginning garbage
-                       } else {                                         //9+ = 10 waves
+                       } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's
+                               dest[numBits++]=1;
+                       } else {                                         //9+ = 10 sample waves
                                dest[numBits++]=0;
                        }
                        last_transition = idx;