From c9b68163d51af68b6603b6a32e06c16b6aa5b6ef Mon Sep 17 00:00:00 2001
From: jgromes <jgromes@users.noreply.github.com>
Date: Tue, 4 Jun 2019 10:13:04 +0200
Subject: [PATCH] [SX126x] Added notes about DIO2 RF control

---
 .../SX126x_Channel_Activity_Detection.ino     |  9 ++++-
 .../SX126x_Settings/SX126x_Settings.ino       |  9 +++++
 keywords.txt                                  |  1 +
 src/TypeDef.h                                 |  2 +-
 src/modules/SX126x.cpp                        | 38 +++++++++----------
 5 files changed, 37 insertions(+), 22 deletions(-)

diff --git a/examples/SX126x/SX126x_Channel_Activity_Detection/SX126x_Channel_Activity_Detection.ino b/examples/SX126x/SX126x_Channel_Activity_Detection/SX126x_Channel_Activity_Detection.ino
index 0750f181..91c53b09 100644
--- a/examples/SX126x/SX126x_Channel_Activity_Detection/SX126x_Channel_Activity_Detection.ino
+++ b/examples/SX126x/SX126x_Channel_Activity_Detection/SX126x_Channel_Activity_Detection.ino
@@ -59,11 +59,16 @@ void loop() {
 
   if (state == LORA_DETECTED) {
     // LoRa preamble was detected
-    Serial.println(F(" detected!"));
+    Serial.println(F("detected!"));
 
   } else if (state == CHANNEL_FREE) {
     // no preamble was detected, channel is free
-    Serial.println(F(" channel is free!"));
+    Serial.println(F("channel is free!"));
+
+  } else if (state == ERR_CAD_UNAVAILABLE) {
+    // no preamble was detected, channel is free
+    Serial.println(F("unable to perform scan!"));
+    Serial.println(F("[SX1262] Disable DIO2 RF control to run CAD."));
 
   }
 
diff --git a/examples/SX126x/SX126x_Settings/SX126x_Settings.ino b/examples/SX126x/SX126x_Settings/SX126x_Settings.ino
index 52553045..7d9114b0 100644
--- a/examples/SX126x/SX126x_Settings/SX126x_Settings.ino
+++ b/examples/SX126x/SX126x_Settings/SX126x_Settings.ino
@@ -13,6 +13,7 @@
     - CRC
     - preamble length
     - TCXO voltage
+    - DIO2 RF switch control
 
    Other modules from SX126x family can also be used.
 
@@ -146,6 +147,14 @@ void setup() {
     while (true);
   }
 
+  // Some SX126x modules use DIO2 as RF switch. To enable
+  // this feature, the following method can be used.
+  // NOTE: As long as DIO2 is configured to control RF switch,
+  //       Channel Activity Detection is disabled!
+  if (loraSX1262.setDio2AsRfSwitch() != ERR_NONE) {
+    Serial.println(F("Failed to set DIO2 as RF switch!"));
+    while (true);
+  }
 
   Serial.println(F("All settings succesfully changed!"));
 }
diff --git a/keywords.txt b/keywords.txt
index 31d82ea1..d9a7b7f2 100644
--- a/keywords.txt
+++ b/keywords.txt
@@ -232,3 +232,4 @@ ERR_INVALID_MODULATION_PARAMETERS	LITERAL1
 ERR_SPI_CMD_TIMEOUT	LITERAL1
 ERR_SPI_CMD_INVALID	LITERAL1
 ERR_SPI_CMD_FAILED	LITERAL1
+ERR_CAD_UNAVAILABLE	LITERAL1
diff --git a/src/TypeDef.h b/src/TypeDef.h
index efda5ef0..6a91a4c9 100644
--- a/src/TypeDef.h
+++ b/src/TypeDef.h
@@ -464,7 +464,7 @@
 /*!
   \brief SX126x scan channel not possible because DIO2 is used as RF antenna switch.
 */
-#define ERR_DIO2_UNAVAIL_CAD_FAILED           -708
+#define ERR_CAD_UNAVAILABLE                  -708
 
 /*!
   \}
diff --git a/src/modules/SX126x.cpp b/src/modules/SX126x.cpp
index 8291857c..17369cab 100644
--- a/src/modules/SX126x.cpp
+++ b/src/modules/SX126x.cpp
@@ -33,11 +33,6 @@ int16_t SX126x::begin(float bw, uint8_t sf, uint8_t cr, uint16_t syncWord, uint1
   }
 
   // configure publicly accessible settings
-  state = setDio2AsRfSwitch(false);
-  if(state != ERR_NONE) {
-    return(state);
-  }
-
   state = setSpreadingFactor(sf);
   if(state != ERR_NONE) {
     return(state);
@@ -59,6 +54,12 @@ int16_t SX126x::begin(float bw, uint8_t sf, uint8_t cr, uint16_t syncWord, uint1
   }
 
   state = setPreambleLength(preambleLength);
+  if(state != ERR_NONE) {
+    return(state);
+  }
+
+  // set publicly accessible settings that are not a part of begin method
+  state = setDio2AsRfSwitch(false);
 
   return(state);
 }
@@ -91,11 +92,6 @@ int16_t SX126x::beginFSK(float br, float freqDev, float rxBw, uint16_t preambleL
   }
 
   // configure publicly accessible settings
-  state = setDio2AsRfSwitch(false);
-  if(state != ERR_NONE) {
-    return(state);
-  }
-
   state = setBitRate(br);
   if(state != ERR_NONE) {
     return(state);
@@ -121,9 +117,14 @@ int16_t SX126x::beginFSK(float br, float freqDev, float rxBw, uint16_t preambleL
     return(state);
   }
 
-  // set default sync word 0x2D01 - not a beginFSK attribute
+  // set publicly accessible settings that are not a part of begin method
   uint8_t sync[] = {0x2D, 0x01};
   state = setSyncWord(sync, 2);
+  if(state != ERR_NONE) {
+    return(state);
+  }
+
+  state = setDio2AsRfSwitch(false);
 
   return(state);
 }
@@ -286,7 +287,7 @@ int16_t SX126x::scanChannel() {
 
   if (_dio2RfSwitch) {
     // If DIO2 is used as RF switch this function does not work
-    return(ERR_DIO2_UNAVAIL_CAD_FAILED);
+    return(ERR_CAD_UNAVAILABLE);
   }
 
   // set mode to standby
@@ -1074,16 +1075,15 @@ int16_t SX126x::setFrequencyRaw(float freq) {
 }
 
 int16_t SX126x::setDio2AsRfSwitch(bool enable) {
-  uint8_t data[1];
-  if (enable) {
-  // set DIO2 as RF switch
-    data[0] = SX126X_DIO2_AS_RF_SWITCH;
+  uint8_t data = 0;
+  if(enable) {
+    data = SX126X_DIO2_AS_RF_SWITCH;
   } else {
-    data[0] = SX126X_DIO2_AS_IRQ;
+    data = SX126X_DIO2_AS_IRQ;
   }
-  int16_t state = SPIwriteCommand(SX126X_CMD_SET_DIO2_AS_RF_SWITCH_CTRL, data, 1);
+  int16_t state = SPIwriteCommand(SX126X_CMD_SET_DIO2_AS_RF_SWITCH_CTRL, &data, 1);
 
-  if (state == ERR_NONE) {
+  if(state == ERR_NONE) {
     _dio2RfSwitch = enable;
   }
   return(state);