From 293fba2656794a3c8141455841b2d6ff70f5abb5 Mon Sep 17 00:00:00 2001
From: Andrea Guglielmini <il.guglio95@gmail.com>
Date: Sun, 16 Feb 2020 15:09:39 +0100
Subject: [PATCH] [CC1101] Added carrier sense as sync word qualifier

---
 src/modules/CC1101/CC1101.cpp | 21 ++++++++++++---------
 src/modules/CC1101/CC1101.h   | 16 ++++++++++++----
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/src/modules/CC1101/CC1101.cpp b/src/modules/CC1101/CC1101.cpp
index 2884ee0d..380658bd 100644
--- a/src/modules/CC1101/CC1101.cpp
+++ b/src/modules/CC1101/CC1101.cpp
@@ -470,7 +470,7 @@ int16_t CC1101::setOutputPower(int8_t power) {
   }
 }
 
-int16_t CC1101::setSyncWord(uint8_t* syncWord, uint8_t len, uint8_t maxErrBits) {
+int16_t CC1101::setSyncWord(uint8_t* syncWord, uint8_t len, uint8_t maxErrBits, bool requireCarrierSense) {
   if((maxErrBits > 1) || (len != 2)) {
     return(ERR_INVALID_SYNC_WORD);
   }
@@ -485,7 +485,7 @@ int16_t CC1101::setSyncWord(uint8_t* syncWord, uint8_t len, uint8_t maxErrBits)
   _syncWordLength = len;
 
   // enable sync word filtering
-  int16_t state = enableSyncWordFiltering(maxErrBits);
+  int16_t state = enableSyncWordFiltering(maxErrBits, requireCarrierSense);
   RADIOLIB_ASSERT(state);
 
   // set sync word register
@@ -495,9 +495,9 @@ int16_t CC1101::setSyncWord(uint8_t* syncWord, uint8_t len, uint8_t maxErrBits)
   return(state);
 }
 
-int16_t CC1101::setSyncWord(uint8_t syncH, uint8_t syncL, uint8_t maxErrBits) {
+int16_t CC1101::setSyncWord(uint8_t syncH, uint8_t syncL, uint8_t maxErrBits, bool requireCarrierSense) {
   uint8_t syncWord[] = { syncH, syncL };
-  return(setSyncWord(syncWord, sizeof(syncWord), maxErrBits));
+  return(setSyncWord(syncWord, sizeof(syncWord), maxErrBits, requireCarrierSense));
 }
 
 int16_t CC1101::setPreambleLength(uint8_t preambleLength) {
@@ -627,21 +627,24 @@ int16_t CC1101::variablePacketLengthMode(uint8_t maxLen) {
   return(setPacketMode(CC1101_LENGTH_CONFIG_VARIABLE, maxLen));
 }
 
-int16_t CC1101::enableSyncWordFiltering(uint8_t maxErrBits) {
+int16_t CC1101::enableSyncWordFiltering(uint8_t maxErrBits, bool requireCarrierSense) {
   switch (maxErrBits){
     case 0:
       // in 16 bit sync word, expect all 16 bits.
-      return (SPIsetRegValue(CC1101_REG_MDMCFG2, CC1101_SYNC_MODE_16_16, 2, 0));
+      return (SPIsetRegValue(CC1101_REG_MDMCFG2,
+        requireCarrierSense ? CC1101_SYNC_MODE_16_16_THR : CC1101_SYNC_MODE_16_16, 2, 0));
     case 1:
       // in 16 bit sync word, expect at least 15 bits.
-      return (SPIsetRegValue(CC1101_REG_MDMCFG2, CC1101_SYNC_MODE_15_16, 2, 0));
+      return (SPIsetRegValue(CC1101_REG_MDMCFG2,
+        requireCarrierSense ? CC1101_SYNC_MODE_15_16_THR : CC1101_SYNC_MODE_15_16, 2, 0));
     default:
       return (ERR_INVALID_SYNC_WORD);
   }
 }
 
-int16_t CC1101::disableSyncWordFiltering() {
-  return(SPIsetRegValue(CC1101_REG_MDMCFG2, CC1101_SYNC_MODE_NONE, 2, 0));
+int16_t CC1101::disableSyncWordFiltering(bool requireCarrierSense) {
+  return(SPIsetRegValue(CC1101_REG_MDMCFG2,
+    requireCarrierSense ? CC1101_SYNC_MODE_NONE_THR : CC1101_SYNC_MODE_NONE, 2, 0));
 }
 
 int16_t CC1101::setCrcFiltering(bool crcOn) {
diff --git a/src/modules/CC1101/CC1101.h b/src/modules/CC1101/CC1101.h
index 0d3e44d9..2486647f 100644
--- a/src/modules/CC1101/CC1101.h
+++ b/src/modules/CC1101/CC1101.h
@@ -709,9 +709,11 @@ class CC1101: public PhysicalLayer {
 
       \param maxErrBits Maximum allowed number of bit errors in received sync word. Defaults to 0.
 
+      \param requireCarrierSense Require carrier sense above threshold in addition to sync word.
+
       \returns \ref status_codes
     */
-    int16_t setSyncWord(uint8_t syncH, uint8_t syncL, uint8_t maxErrBits = 0);
+    int16_t setSyncWord(uint8_t syncH, uint8_t syncL, uint8_t maxErrBits = 0, bool requireCarrierSense = false);
 
     /*!
       \brief Sets 1 or 2 bytes of sync word.
@@ -722,9 +724,11 @@ class CC1101: public PhysicalLayer {
 
       \param maxErrBits Maximum allowed number of bit errors in received sync word. Defaults to 0.
 
+      \param requireCarrierSense Require carrier sense above threshold in addition to sync word.
+
       \returns \ref status_codes
     */
-    int16_t setSyncWord(uint8_t* syncWord, uint8_t len, uint8_t maxErrBits = 0);
+    int16_t setSyncWord(uint8_t* syncWord, uint8_t len, uint8_t maxErrBits = 0, bool requireCarrierSense = false);
 
     /*!
       \brief Sets preamble length.
@@ -808,16 +812,20 @@ class CC1101: public PhysicalLayer {
 
       \param numBits Sync word length in bits.
 
+      \param requireCarrierSense Require carrier sense above threshold in addition to sync word.
+
       \returns \ref status_codes
     */
-    int16_t enableSyncWordFiltering(uint8_t maxErrBits = 0);
+    int16_t enableSyncWordFiltering(uint8_t maxErrBits = 0, bool requireCarrierSense = false);
 
      /*!
       \brief Disable preamble and sync word filtering and generation.
 
+      \param requireCarrierSense Require carrier sense above threshold.
+
       \returns \ref status_codes
     */
-    int16_t disableSyncWordFiltering();
+    int16_t disableSyncWordFiltering(bool requireCarrierSense = false);
 
      /*!
       \brief Enable CRC filtering and generation.