update changelog

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index f13a567c6fe8cda87b1cf70248cd201603fe023f..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; 
        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
        // 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
 
                // 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
                                //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;
                                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
                                //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;
                                dest[numBits++]=0;
                        }
                        last_transition = idx;


@@ -580,7 +591,7 @@ int IOdemodFSK(uint8_t *dest, size_t size)
 
 // by marshmellow
 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
 
 // by marshmellow
 // takes a array of binary values, start position, length of bits per parity (includes parity bit),

-//   Parity Type (1 for odd; 0 for even; 2 for just drop it), and binary Length (length to run) 
+//   Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run) 

 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
 {
        uint32_t parityWd = 0;
 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
 {
        uint32_t parityWd = 0;


@@ -590,10 +601,12 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p
                        parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
                        BitStream[j++] = (BitStream[startIdx+word+bit]);
                }
                        parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
                        BitStream[j++] = (BitStream[startIdx+word+bit]);
                }

-               j--;
+               j--; // overwrite parity with next data

                // if parity fails then return 0
                // if parity fails then return 0

-               if (pType != 2) {
-                       if (parityTest(parityWd, pLen, pType) == 0) return -1;
+               if (pType == 2) { // then marker bit which should be a 1
+                       if (!BitStream[j]) return 0;
+               } else {
+                       if (parityTest(parityWd, pLen, pType) == 0) return 0;                   

                }
                bitCnt+=(pLen-1);
                parityWd = 0;
                }
                bitCnt+=(pLen-1);
                parityWd = 0;