ADD: LF JABLOTRON functionality. with clone/sim and detection in LF SEARCH.

CHG: removed no-existing crc8ja code
FIX: a check in ASKbiphaseDemod to make sure graphbuff is not empty.

common/crc.c

@@ -94,17 +94,6 @@ uint32_t CRC8Legic(uint8_t *buff, size_t size) {
 	return reflect(crc_finish(&crc), 8);
 }
 
-// credits to marshmellow
-// width=8  poly=0xA3, reversed poly=0x8B,  init=0xB0  refin=true  refout=true  xorout=0x00  check=0x28  name="CRC-8/JA"
-uint32_t CRC8ja(uint8_t *buff, size_t size) {
-	crc_t crc;
-	crc_init_ref(&crc, 8, 0xA3, 0x42, 0x00, TRUE, TRUE);
-	for ( int i=0; i < size; ++i)
-		crc_update(&crc, buff[i], 8);
-	return crc_finish(&crc);
-	//return reflect(crc_finish(&crc), 8);
-}
-
 // This CRC-16 is used in Legic Advant systems. 
 // width=8  poly=0xB400, reversed poly=0x  init=depends  refin=true  refout=true  xorout=0x0000  check=  name="CRC-16/LEGIC"
 uint32_t CRC16Legic(uint8_t *buff, size_t size, uint8_t uidcrc) {

common/crc.h

@@ -65,9 +65,6 @@ uint32_t CRC8Legic(uint8_t *buff, size_t size);
 // ie:  uidcrc = 0x78  then initial_value == 0x7878
 uint32_t CRC16Legic(uint8_t *buff, size_t size, uint8_t uidcrc);
 
-// Calculate CRC-8/ja checksum
-uint32_t CRC8ja(uint8_t *buff, size_t size);
-
 // test crc 16.
 uint32_t CRC16_DNP(uint8_t *buff, size_t size);
 uint32_t CRC16_CCITT(uint8_t *buff, size_t size);

common/lfdemod.c

@@ -723,6 +723,33 @@ 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};
+
+	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+	if (errChk == 0) return -4; //preamble not found
+	
+	uint8_t checkCalc = 0;
+	for (int i=16; i < 56; i += 8) {
+		checkCalc += bytebits_to_byte(dest+startIdx+i,8);
+	}
+	checkCalc ^= 0x3A;
+
+	uint8_t crc = bytebits_to_byte(dest+startIdx+56,8);
+	
+	if ( checkCalc != crc ) return -5;	
+	if (*size != 64) return -6;
+	return (int)startIdx;
+}
+
 // by marshmellow
 // FSK Demod then try to locate an AWID ID
 int AWIDdemodFSK(uint8_t *dest, size_t *size)

common/lfdemod.h

@@ -56,4 +56,5 @@ int PyramiddemodFSK(uint8_t *dest, size_t *size);
 int VikingDemod_AM(uint8_t *dest, size_t *size);
 int PrescoDemod(uint8_t *dest, size_t *size);
 int NedapDemod(uint8_t *dest, size_t *size);
+int JablotronDemod(uint8_t *dest, size_t *size);
 #endif