From 7eb1feba7c7a64910cb17f741f2349254a34fddd Mon Sep 17 00:00:00 2001
From: Josh Allen <axlecrusher@gmail.com>
Date: Sat, 11 Feb 2017 10:08:16 -0500
Subject: ootx payload length for lighthouse 1 seems to be decoding correctly
 at 0x21. the payload length seems to be oscillating between 0x21 and a much
 larger number. the larger number 0xc8ec I have no idea why. 0xc8ec does not
 last long before a new preamble is found

---
 tools/ootx_decode/ootx_decoder.c | 74 ++++++++++++++++++++++++++++++++++------
 1 file changed, 63 insertions(+), 11 deletions(-)

(limited to 'tools/ootx_decode/ootx_decoder.c')

diff --git a/tools/ootx_decode/ootx_decoder.c b/tools/ootx_decode/ootx_decoder.c
index b386132..6ec0857 100644
--- a/tools/ootx_decode/ootx_decoder.c
+++ b/tools/ootx_decode/ootx_decoder.c
@@ -16,6 +16,7 @@
 #define MAX_BUFF_SIZE 1024
 
 void (*ootx_packet_clbk)(ootx_packet* packet) = NULL;
+void ootx_pump_bit(ootx_decoder_context *ctx, uint8_t dbit);
 
 void ootx_init_decoder_context(ootx_decoder_context *ctx) {
 	ctx->buf_offset = 0;
@@ -45,26 +46,70 @@ void ootx_init_buffer() {
 
 int8_t ootx_decode_lighthouse_number(uint8_t last_num, uint32_t ticks, int32_t delta) {
 	if (ticks<2000) return -1; //sweep
-	if ((ticks > 2000) & (delta>100000)) return 0; //master
-	if ((ticks > 2000) & (delta>10000)) return last_num+1; //a slave
+	if (delta>100000) return 0; //master
+	if (delta>10000) return 1; //a slave
 	return -1;
 }
 
+uint8_t decode_internal(uint32_t length) {
+		uint16_t temp = length - 2880;
+//		printf
 
-uint8_t ootx_decode_bit(uint32_t ticks) {
-	ticks = ((ticks/500)*500)+500;
+#if BETTER_SAFE_THAN_FAST
+	if (temp < 0 || length > 6525) {
+		return -1;
+	}
+#endif
+
+	if ((temp % 500) < 150) {
+		return temp / 500;
+	}
 
-	ticks-=3000;
-	if (ticks>=2000) { ticks-=2000; }
-	if (ticks>=1000)  { return 0xFF; }
+	return -1;
+
+}
+
+uint8_t ootx_decode_bit(uint32_t length) {
+	length = ((length/500)*500)+500;
+
+	length-=3000;
+	if (length>=2000) { length-=2000; }
+	if (length>=1000)  { return 0xFF; }
 
 	return 0x00;
 }
+/*
+uint8_t ootx_decode_bit(uint32_t ticks) {
+	int8_t bits = decode_internal(ticks);
+	return bits&0x02;
+}
+*/
+
+void ootx_log_bit(ootx_decoder_context *ctx, uint32_t ticks) {
+	int8_t dbit = ootx_decode_bit(ticks);
+//	printf("%d\n\n", dbit);
+	ctx->bit_count[(dbit&0x01)]++;
+//	printf("%d %d %d\n", dbit, ctx->bit_count[0], ctx->bit_count[1]);
+}
+
+void ootx_pump_greatest_bit(ootx_decoder_context *ctx) {
+	//pump the bit
+	if (ctx->bit_count[0] > ctx->bit_count[1]) {
+//		printf("Pump 0x00\n");
+		ootx_pump_bit( ctx, 0x00 );
+	} else {
+//		printf("Pump 0xFF\n");
+		ootx_pump_bit( ctx, 0xFF );
+	}
+
+	ctx->bit_count[0] = 0;
+	ctx->bit_count[1] = 0;
+}
 
 uint8_t ootx_detect_preamble(ootx_decoder_context *ctx, uint8_t dbit) {
 	ctx->preamble <<= 1;
 	ctx->preamble |= (0x01 & dbit);
-	if ((ctx->preamble & 0x0001ffff) == 0x01) return 1;
+	if ((ctx->preamble & 0x0001ffff) == 0x00000001) return 1;
 	return 0;
 }
 
@@ -92,8 +137,10 @@ void ootx_inc_buffer_offset(ootx_decoder_context *ctx) {
 void ootx_write_to_buffer(ootx_decoder_context *ctx, uint8_t dbit) {
 	uint8_t *current_byte = ctx->buffer + ctx->buf_offset;
 //	printf("%d\n", dbit);
-	*current_byte >>= 1;
-	*current_byte |= (0x80 & dbit);
+//	*current_byte >>= 1;
+//	*current_byte |= (0x80 & dbit);
+	*current_byte <<= 1;
+	*current_byte |= (0x01 & dbit);
 	++(ctx->bits_written);
 	if (ctx->bits_written>7) {
 		ctx->bits_written=0;
@@ -103,7 +150,12 @@ void ootx_write_to_buffer(ootx_decoder_context *ctx, uint8_t dbit) {
 }
 
 void ootx_process_bit(ootx_decoder_context *ctx, uint32_t length) {
-	uint8_t dbit = ootx_decode_bit(length);
+	int8_t dbit = ootx_decode_bit(length);
+	ootx_pump_bit( ctx, dbit );
+}
+
+void ootx_pump_bit(ootx_decoder_context *ctx, uint8_t dbit) {
+//	uint8_t dbit = ootx_decode_bit(length);
 	++(ctx->bits_processed);
 
 //	printf("z %d %d\n", bits_processed,dbit);
-- 
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