From ac4ea556ae18ee45516c0d9439d1550f3d0853f3 Mon Sep 17 00:00:00 2001
From: Libor Tomsik <libor@tomsik.eu>
Date: Thu, 15 Apr 2021 08:37:47 +0200
Subject: [PATCH] Implemented AFC&AGC trigger control

---
 src/modules/SX127x/SX127x.cpp | 45 ++++++++++++++++++++++++++---------
 src/modules/SX127x/SX127x.h   | 18 ++++++++++++++
 2 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/src/modules/SX127x/SX127x.cpp b/src/modules/SX127x/SX127x.cpp
index ae9f3995..2cd50cd1 100644
--- a/src/modules/SX127x/SX127x.cpp
+++ b/src/modules/SX127x/SX127x.cpp
@@ -92,7 +92,11 @@ int16_t SX127x::beginFSK(uint8_t chipVersion, float br, float freqDev, float rxB
   state = SX127x::setAFCBandwidth(rxBw);
   RADIOLIB_ASSERT(state);
 
-  state = _mod->SPIsetRegValue(SX127X_REG_RX_CONFIG, 0x1E);//TODO
+  //sets AFC&AGC trigger to RSSI and preamble detect
+  state = SX127x::setAFCAGCTrigger(SX127X_RX_TRIGGER_BOTH);
+  RADIOLIB_ASSERT(state);
+
+  state = SX127x::setAFC(true);
   RADIOLIB_ASSERT(state);
 
   // set receiver bandwidth
@@ -768,19 +772,38 @@ int16_t SX127x::setRxBandwidth(float rxBw) {
 }
 
 int16_t SX127x::setAFCBandwidth(float rxBw){
-    // check active modem
-    if(getActiveModem() != SX127X_FSK_OOK){
-        return(ERR_WRONG_MODEM);
-    }
+  // check active modem
+  if(getActiveModem() != SX127X_FSK_OOK){
+      return(ERR_WRONG_MODEM);
+  }
 
-    RADIOLIB_CHECK_RANGE(rxBw, 2.6, 250.0, ERR_INVALID_RX_BANDWIDTH);
+  RADIOLIB_CHECK_RANGE(rxBw, 2.6, 250.0, ERR_INVALID_RX_BANDWIDTH);
 
-    // set mode to STANDBY
-    int16_t state = setMode(SX127X_STANDBY);
-    RADIOLIB_ASSERT(state);
+  // set mode to STANDBY
+  int16_t state = setMode(SX127X_STANDBY);
+  RADIOLIB_ASSERT(state);
 
-    // set AFC bandwidth
-    return(_mod->SPIsetRegValue(SX127X_REG_AFC_BW, calculateBWManExp(rxBw), 4, 0));
+  // set AFC bandwidth
+  return(_mod->SPIsetRegValue(SX127X_REG_AFC_BW, calculateBWManExp(rxBw), 4, 0));
+}
+
+int16_t SX127x::setAFC(bool isEnabled){
+  // check active modem
+  if(getActiveModem() != SX127X_FSK_OOK) {
+    return(ERR_WRONG_MODEM);
+  }
+
+  //set AFC auto on/off
+  return(_mod->SPIsetRegValue(SX127X_REG_RX_CONFIG, isEnabled ? SX127X_AFC_AUTO_ON : SX127X_AFC_AUTO_OFF, 4, 4));
+}
+
+int16_t SX127x::setAFCAGCTrigger(uint8_t trigger){
+  if(getActiveModem() != SX127X_FSK_OOK) {
+    return(ERR_WRONG_MODEM);
+  }
+
+  //set AFC&AGC trigger
+  return(_mod->SPIsetRegValue(SX127X_REG_RX_CONFIG, trigger, 2, 0));
 }
 
 int16_t SX127x::setSyncWord(uint8_t* syncWord, size_t len) {
diff --git a/src/modules/SX127x/SX127x.h b/src/modules/SX127x/SX127x.h
index 7508f6c6..e16c8cdf 100644
--- a/src/modules/SX127x/SX127x.h
+++ b/src/modules/SX127x/SX127x.h
@@ -823,6 +823,24 @@ class SX127x: public PhysicalLayer {
     */
     int16_t setAFCBandwidth(float afcBw);
 
+    /*!
+      \brief Enables or disables FSK automatic frequency correction(AFC)
+
+      \param isEnabled AFC enabled or disabled
+
+      \return \ref status_codes
+    */
+    int16_t setAFC(bool isEnabled);
+
+    /*!
+      \brief Controls trigger of AFC and AGC
+
+      \param trigger one from SX127X_RX_TRIGGER_NONE, SX127X_RX_TRIGGER_RSSI_INTERRUPT, SX127X_RX_TRIGGER_PREAMBLE_DETECT, SX127X_RX_TRIGGER_BOTH
+
+      \return \ref status_codes
+    */
+    int16_t setAFCAGCTrigger(uint8_t trigger);
+
     /*!
       \brief Sets FSK sync word. Allowed sync words are up to 8 bytes long and can not contain null bytes. Only available in FSK mode.