From 7d7af7ac0b7ea292a528c576242eaa8f5af0cebf Mon Sep 17 00:00:00 2001
From: Andrea Guglielmini <il.guglio95@gmail.com>
Date: Mon, 18 Nov 2019 17:01:37 +0100
Subject: [PATCH] Variable PreambleLength for CC1101

---
 src/modules/CC1101.cpp | 37 +++++++++++++++++++++++++++++++++++++
 src/modules/CC1101.h   |  9 +++++++++
 2 files changed, 46 insertions(+)

diff --git a/src/modules/CC1101.cpp b/src/modules/CC1101.cpp
index 657400a0..8c1a5ab1 100644
--- a/src/modules/CC1101.cpp
+++ b/src/modules/CC1101.cpp
@@ -448,6 +448,43 @@ int16_t CC1101::setSyncWord(uint8_t syncH, uint8_t syncL) {
   return(state);
 }
 
+int16_t CC1101::setPreambleLength(uint8_t preambleLength) {
+  // check allowed values
+  uint8_t value;
+  switch(preambleLength){
+    case 2:
+      value = CC1101_NUM_PREAMBLE_2;
+      break;
+    case 3:
+      value = CC1101_NUM_PREAMBLE_3;
+      break;
+    case 4:
+      value = CC1101_NUM_PREAMBLE_4;
+      break;
+    case 6:
+      value = CC1101_NUM_PREAMBLE_6;
+      break;
+    case 8:
+      value = CC1101_NUM_PREAMBLE_8;
+      break;
+    case 12:
+      value = CC1101_NUM_PREAMBLE_12;
+      break;
+    case 16:
+      value = CC1101_NUM_PREAMBLE_16;
+      break;
+    case 24:
+      value = CC1101_NUM_PREAMBLE_24;
+      break;
+    default:
+      return(ERR_INVALID_PREAMBLE_LENGTH);
+  }
+
+
+  return SPIsetRegValue(CC1101_REG_MDMCFG1, value, 6, 4);
+}
+
+
 int16_t CC1101::setNodeAddress(uint8_t nodeAddr, uint8_t numBroadcastAddrs) {
   if(!(numBroadcastAddrs > 0) && (numBroadcastAddrs <= 2)) {
     return(ERR_INVALID_NUM_BROAD_ADDRS);
diff --git a/src/modules/CC1101.h b/src/modules/CC1101.h
index c57a7e6d..16b23a6e 100644
--- a/src/modules/CC1101.h
+++ b/src/modules/CC1101.h
@@ -698,6 +698,15 @@ class CC1101: public PhysicalLayer {
     */
     int16_t setSyncWord(uint8_t syncH, uint8_t syncL);
 
+    /*!
+      \brief Sets preamble length.
+
+      \param preambleLength Preamble length to be set, allowed values: 2, 3, 4, 6, 8, 12, 16, 24
+
+      \returns \ref status_codes
+    */
+    int16_t setPreambleLength(uint8_t preambleLength);
+
     /*!
       \brief Sets node and broadcast addresses. Calling this method will also enable address filtering.