From 11081e0459f303518350b195b9d1c54b415eb6d7 Mon Sep 17 00:00:00 2001
From: marshmellow42 <marshmellowrf@gmail.com>
Date: Tue, 3 Mar 2015 16:20:18 -0500
Subject: [PATCH] finish gProxII_Demod

---
 common/lfdemod.c | 23 ++++++++++++++++++++++-
 common/lfdemod.h |  1 +
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/common/lfdemod.c b/common/lfdemod.c
index bee87ece..144cb327 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -354,7 +354,6 @@ void askAmp(uint8_t *BitStream, size_t size)
 //by marshmellow
 //takes 3 arguments - clock, invert and maxErr as integers
 //attempts to demodulate ask only
-//prints binary found and saves in graphbuffer for further commands
 int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp)
 {
 	uint32_t i;
@@ -501,6 +500,28 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int max
 	}
 	return bestErrCnt;
 }
+
+// demod gProxIIDemod 
+// error returns as -x 
+// success returns start position in BitStream
+// BitStream must contain previously askrawdemod and biphasedemoded data
+int gProxII_Demod(uint8_t BitStream[], size_t *size)
+{
+	size_t startIdx=0;
+	uint8_t preamble[] = {1,1,1,1,1,0};
+
+	uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
+	if (errChk == 0) return -3; //preamble not found
+	if (*size != 96) return -2; //should have found 96 bits
+	//check first 6 spacer bits to verify format
+	if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
+		//confirmed proper separator bits found
+		//return start position
+		return (int) startIdx;
+	}
+	return -5;
+}
+
 //translate wave to 11111100000 (1 for each short wave 0 for each long wave)
 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
 {
diff --git a/common/lfdemod.h b/common/lfdemod.h
index 9d55d064..23525a48 100644
--- a/common/lfdemod.h
+++ b/common/lfdemod.h
@@ -22,6 +22,7 @@ int ManchesterEncode(uint8_t *BitStream, size_t size);
 int manrawdecode(uint8_t *BitStream, size_t *size);
 int BiphaseRawDecode(uint8_t * BitStream, size_t *size, int offset, int invert);
 int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp);
+int gProxII_Demod(uint8_t BitStream[], size_t *size);
 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo);
 int IOdemodFSK(uint8_t *dest, size_t size);
 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow);
-- 
2.39.5