X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/56bbb25a4114df189f66dc8c14d233187e40b042..987c59849ef113c8111e7b3a7067b87a6837c882:/common/lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 3bc246a3..7e31f53d 100644
--- 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
@@ -721,6 +723,39 @@ int FDXBdemodBI(uint8_t *dest, size_t *size)
 	return (int)startIdx;
 }
 
+// ASK/Diphase fc/64 (inverted Biphase)
+// Note: this i s not a demod, this is only a detection
+// the parameter *dest needs to be demoded before call
+int JablotronDemod(uint8_t *dest, size_t *size){
+	//make sure buffer has enough data
+	if (*size < 64) return -1;
+
+	size_t startIdx = 0;
+	// 0xFFFF preamble, 64bits
+	uint8_t preamble[] = {
+		        1,1,1,1,
+	            1,1,1,1,
+				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
+	if (*size != 64) return -3;
+	
+	uint8_t checkchksum = 0;
+	for (int i=16; i < 56; i += 8) {
+		checkchksum += bytebits_to_byte(dest+startIdx+i,8);
+	}
+	checkchksum ^= 0x3A;
+
+	uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
+	
+	if ( checkchksum != crc ) return -5;	
+	return (int)startIdx;
+}
+
 // by marshmellow
 // FSK Demod then try to locate an AWID ID
 int AWIDdemodFSK(uint8_t *dest, size_t *size)
@@ -764,15 +799,16 @@ int PyramiddemodFSK(uint8_t *dest, size_t *size)
 	return (int)startIdx;
 }
 
-// find presco preamble 0x10D in already demoded data
+// 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 start position
 	return (int) startIdx;
 }