From 96405b938da6a7f93a1b1220901d58d4b773982f Mon Sep 17 00:00:00 2001
From: jgromes <jgromes@users.noreply.github.com>
Date: Wed, 8 Jul 2020 18:52:08 +0200
Subject: [PATCH] [SX126x] Added methods to manually set LoRa LDRO

---
 src/modules/SX126x/SX126x.cpp | 31 ++++++++++++++++++++++++++-----
 src/modules/SX126x/SX126x.h   | 21 ++++++++++++++++++++-
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/src/modules/SX126x/SX126x.cpp b/src/modules/SX126x/SX126x.cpp
index b5b0d8b9..fbd0edf4 100644
--- a/src/modules/SX126x/SX126x.cpp
+++ b/src/modules/SX126x/SX126x.cpp
@@ -650,7 +650,7 @@ int16_t SX126x::setBandwidth(float bw) {
 
   // update modulation parameters
   _bwKhz = bw;
-  return(setModulationParams(_sf, _bw, _cr));
+  return(setModulationParams(_sf, _bw, _cr, _ldro));
 }
 
 int16_t SX126x::setSpreadingFactor(uint8_t sf) {
@@ -663,7 +663,7 @@ int16_t SX126x::setSpreadingFactor(uint8_t sf) {
 
   // update modulation parameters
   _sf = sf;
-  return(setModulationParams(_sf, _bw, _cr));
+  return(setModulationParams(_sf, _bw, _cr, _ldro));
 }
 
 int16_t SX126x::setCodingRate(uint8_t cr) {
@@ -676,7 +676,7 @@ int16_t SX126x::setCodingRate(uint8_t cr) {
 
   // update modulation parameters
   _cr = cr - 4;
-  return(setModulationParams(_sf, _bw, _cr));
+  return(setModulationParams(_sf, _bw, _cr, _ldro));
 }
 
 int16_t SX126x::setSyncWord(uint8_t syncWord, uint8_t controlBits) {
@@ -1152,6 +1152,27 @@ void SX126x::setRfSwitchPins(RADIOLIB_PIN_TYPE rxEn, RADIOLIB_PIN_TYPE txEn) {
   _mod->setRfSwitchPins(rxEn, txEn);
 }
 
+int16_t SX126x::forceLDRO(bool enable) {
+  // check active modem
+  if(getPacketType() != SX126X_PACKET_TYPE_LORA) {
+    return(ERR_WRONG_MODEM);
+  }
+
+  // update modulation parameters
+  _ldroAuto = false;
+  _ldro = (uint8_t)enable;
+  return(setModulationParams(_sf, _bw, _cr, _ldro));
+}
+
+int16_t SX126x::autoLDRO() {
+  if(getPacketType() != SX126X_PACKET_TYPE_LORA) {
+    return(ERR_WRONG_MODEM);
+  }
+
+  _ldroAuto = true;
+  return(ERR_NONE);
+}
+
 int16_t SX126x::setTCXO(float voltage, uint32_t delay) {
   // set mode to standby
   standby();
@@ -1316,8 +1337,8 @@ int16_t SX126x::setHeaderType(uint8_t headerType, size_t len) {
 }
 
 int16_t SX126x::setModulationParams(uint8_t sf, uint8_t bw, uint8_t cr, uint8_t ldro) {
-  // calculate symbol length and enable low data rate optimization, if needed
-  if(ldro == 0xFF) {
+  // calculate symbol length and enable low data rate optimization, if auto-configuration is enabled
+  if(_ldroAuto) {
     float symbolLength = (float)(uint32_t(1) << _sf) / (float)_bwKhz;
     RADIOLIB_DEBUG_PRINT("Symbol length: ");
     RADIOLIB_DEBUG_PRINT(symbolLength);
diff --git a/src/modules/SX126x/SX126x.h b/src/modules/SX126x/SX126x.h
index 0461e10b..3d45266a 100644
--- a/src/modules/SX126x/SX126x.h
+++ b/src/modules/SX126x/SX126x.h
@@ -852,6 +852,24 @@ class SX126x: public PhysicalLayer {
    */
    void setRfSwitchPins(RADIOLIB_PIN_TYPE rxEn, RADIOLIB_PIN_TYPE txEn);
 
+   /*!
+     \brief Forces LoRa low data rate optimization. Only available in LoRa mode. After calling this method, LDRO will always be set to
+     the provided value, regardless of symbol length. To re-enable automatic LDRO configuration, call SX1278::autoLDRO()
+
+     \param enable Force LDRO to be always enabled (true) or disabled (false).
+
+     \returns \ref status_codes
+   */
+   int16_t forceLDRO(bool enable);
+
+   /*!
+     \brief Re-enables automatic LDRO configuration. Only available in LoRa mode. After calling this method, LDRO will be enabled automatically
+     when symbol length exceeds 16 ms.
+
+     \returns \ref status_codes
+   */
+   int16_t autoLDRO();
+
 #ifndef RADIOLIB_GODMODE
   protected:
 #endif
@@ -871,7 +889,7 @@ class SX126x: public PhysicalLayer {
     int16_t calibrateImage(uint8_t* data);
     uint8_t getPacketType();
     int16_t setTxParams(uint8_t power, uint8_t rampTime = SX126X_PA_RAMP_200U);
-    int16_t setModulationParams(uint8_t sf, uint8_t bw, uint8_t cr, uint8_t ldro = 0xFF);
+    int16_t setModulationParams(uint8_t sf, uint8_t bw, uint8_t cr, uint8_t ldro);
     int16_t setModulationParamsFSK(uint32_t br, uint8_t pulseShape, uint8_t rxBw, uint32_t freqDev);
     int16_t setPacketParams(uint16_t preambleLength, uint8_t crcType, uint8_t payloadLength, uint8_t headerType, uint8_t invertIQ = SX126X_LORA_IQ_STANDARD);
     int16_t setPacketParamsFSK(uint16_t preambleLength, uint8_t crcType, uint8_t syncWordLength, uint8_t addrComp, uint8_t whitening, uint8_t packetType = SX126X_GFSK_PACKET_VARIABLE, uint8_t payloadLength = 0xFF, uint8_t preambleDetectorLength = SX126X_GFSK_PREAMBLE_DETECT_16);
@@ -901,6 +919,7 @@ class SX126x: public PhysicalLayer {
     uint8_t _bw = 0, _sf = 0, _cr = 0, _ldro = 0, _crcType = 0, _headerType = 0;
     uint16_t _preambleLength = 0;
     float _bwKhz = 0;
+    bool _ldroAuto = true;
 
     uint32_t _br = 0, _freqDev = 0;
     uint8_t _rxBw = 0, _pulseShape = 0, _crcTypeFSK = 0, _syncWordLength = 0, _addrComp = 0, _whitening = 0, _packetType = 0;