From 9debe084fca8992efdf0f08bfed343de0987629e Mon Sep 17 00:00:00 2001
From: jaseg <git-bigdata-wsl-arch@jaseg.de>
Date: Mon, 9 Mar 2020 13:23:35 +0100
Subject: demod wip

---
 controller/fw/src/dsss_demod.h | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

(limited to 'controller/fw/src/dsss_demod.h')

diff --git a/controller/fw/src/dsss_demod.h b/controller/fw/src/dsss_demod.h
index 30ec3f7..b9e75d2 100644
--- a/controller/fw/src/dsss_demod.h
+++ b/controller/fw/src/dsss_demod.h
@@ -5,6 +5,9 @@
 #define DSSS_GOLD_CODE_COUNT    ((1<<DSSS_GOLD_CODE_NBITS) + 1)
 #define DSSS_CORRELATION_LENGTH (DSSS_GOLD_CODE_LENGTH * DSSS_DECIMATION)
 
+/* FIXME: move to makefile */
+#define DSSS_MATCHER_CACHE_SIZE 8
+/* FIXME: move to more appropriate header */
 #define PAYLOAD_DATA_BYTE ((PAYLOAD_DATA_BIT+7)/8)
 
 struct iir_biquad {
@@ -20,22 +23,26 @@ struct cwt_iir_filter_state {
     struct iir_biquad_state st[3];
 };
 
-struct {
+struct group {
     int len; /* length of group in samples */
     float max; /* signed value of largest peak in group on any channel */
     uint64_t max_ts; /* absolute position of above peak */
     int max_ch; /* channel (gold sequence index) of above peak */
-} group;
+};
 
-struct decoder_state {
-    int last_phase;
+struct matcher_state {
+    int last_phase; /* 0 .. DSSS_CORRELATION_LENGTH */
     int candidate_phase;
 
     float last_score;
     float candidate_score;
 
-    uint8_t data[PAYLOAD_DATA_BYTE]; 
+#if DSSS_GOLD_CODE_NBITS > 7
+#error DSSS_GOLD_CODE_NBITS is too large for matcher_state.data data type (uint8_t)
+#endif
+    uint8_t data[TRANSMISSION_SYMBOLS]; 
     int data_pos;
+    uint8_t candidate_data;
 };
 
 struct dsss_demod_state {
@@ -49,9 +56,13 @@ struct dsss_demod_state {
 
     struct group group;
 
-    struct group group_cache[DSSS_GROUP_CACHE_SIZE];
+    struct matcher_state matcher_cache[DSSS_MATCHER_CACHE_SIZE];
 };
 
+
+extern void handle_dsss_received(uint8_t data[TRANSMISSION_SYMBOLS]);
+
+void dsss_demod_init(struct dsss_demod_state *st);
 #ifdef SIMULATION
 void dsss_demod_step(struct dsss_demod_state *st, float new_value, uint64_t ts, int record_channel);
 #else /* SIMULATION */
-- 
cgit