CHG: merged the forum user @jason 's fixes to LEGIC. *UNTESTED*

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index cb3e9f0b8a417aa9198262b38d0df42000a1bddd..8b31f1a4c10a751cd447d2667aa89f7a57a7e22e 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -259,13 +259,15 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int
 //by marshmellow
 void askAmp(uint8_t *BitStream, size_t size)
 {
-       for(size_t i = 1; i<size; i++){
-               if (BitStream[i]-BitStream[i-1]>=30) //large jump up
-                       BitStream[i]=255;
-               else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
-                       BitStream[i]=0;
+       uint8_t last = 128;
+       for(size_t i = 1; i < size; ++i){
+               if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
+                       last = 255;
+               else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
+                       last = 0;
+               
+               BitStream[i] = last;
        }
-       return;
 }
 
 //by marshmellow
@@ -679,10 +681,15 @@ int VikingDemod_AM(uint8_t *dest, size_t *size) {
        uint8_t preamble[] = {1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
        uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
        if (errChk == 0) return -4; //preamble not found
-       uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
-           ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8) 
-           ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
-       if ( checkCalc != 0xA8 ) return -5;
+       uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ 
+                                                bytebits_to_byte(dest+startIdx+8,8) ^ 
+                                                bytebits_to_byte(dest+startIdx+16,8) ^ 
+                                                bytebits_to_byte(dest+startIdx+24,8) ^ 
+                                                bytebits_to_byte(dest+startIdx+32,8) ^ 
+                                                bytebits_to_byte(dest+startIdx+40,8) ^ 
+                                                bytebits_to_byte(dest+startIdx+48,8) ^ 
+                                                bytebits_to_byte(dest+startIdx+56,8);
+       if ( checkCalc != 0xA8 ) return -5;     
        if (*size != 64) return -6;
        //return start position
        return (int) startIdx;
@@ -759,6 +766,19 @@ int PyramiddemodFSK(uint8_t *dest, size_t *size)
        return (int)startIdx;
 }
 
+// find nedap preamble in already demoded data
+int NedapDemod(uint8_t *dest, size_t *size) {
+       //make sure buffer has data
+       if (*size < 128) return -3;
+
+       size_t startIdx = 0;
+       //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
+       uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+       return (int) startIdx;
+}
+
 // by marshmellow
 // to detect a wave that has heavily clipped (clean) samples
 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)