Implemented optimal PA settings for SX1268.

Ensured OCP is always restored when changing power.
Slight refactor to avoid duplicated SX1262 / SX1268 code.

src/modules/SX1261.cpp

@@ -14,27 +14,33 @@ int16_t SX1261::setOutputPower(int8_t power) {
     return(state);
   }
 
-  // set PA config for optimal consumption as described in section 13-21 of the datasheet:
+  state = setOptimalLowPowerPaConfig(&power);
-  // the final column of Table 13-21 suggests that the value passed in SetTxParams is actually scaled depending on the parameters of setPaConfig. However, testing suggests this isn't the case.
+
-  if (power > 10) {
+  // set output power
+  // TODO power ramp time configuration
+  if (state == ERR_NONE) {
+    state = SX126x::setTxParams(power);
+  }
+
+  // restore OCP configuration
+  int16_t state2 = writeRegister(SX126X_REG_OCP_CONFIGURATION, &ocp, 1);
+
+  if (state != ERR_NONE) {
+    return state;
+  } else {
+    return state2;
+  }
+}
+
+int16_t SX1261::setOptimalLowPowerPaConfig(int8_t* inOutPower)
+{
+  int16_t state;
+  if (*inOutPower > 10) {
     state = SX126x::setPaConfig(0x04, SX126X_PA_CONFIG_SX1261, 0x00);
   }
   else {
     state = SX126x::setPaConfig(0x01, SX126X_PA_CONFIG_SX1261, 0x00);
+    *inOutPower -= 4;
   }
-  if (state != ERR_NONE) {
+  return state;
-    return(state);
-  }
-  // TODO investigate if better power efficiency can be achieved using undocumented even lower settings
-
-  // set output power
-  // TODO power ramp time configuration
-  state = SX126x::setTxParams(power);
-  if (state != ERR_NONE) {
-    return state;
-  }
-
-
-  // restore OCP configuration
-  return(writeRegister(SX126X_REG_OCP_CONFIGURATION, &ocp, 1));
 }

src/modules/SX1261.h

@@ -6,23 +6,23 @@
 #include "SX126x.h"
 #include "SX1262.h"
 
-//SX126X_CMD_SET_PA_CONFIG
-#define SX126X_PA_CONFIG_SX1261                       0x01
-#define SX126X_PA_CONFIG_SX1262                       0x00
 
 // TODO: implement SX1261 class
 class SX1261 : public SX1262 {
-public:
+  public:
-  /*!
+    /*!
-    \brief Default constructor.
+      \brief Default constructor.
 
-    \param mod Instance of Module that will be used to communicate with the radio.
+      \param mod Instance of Module that will be used to communicate with the radio.
-  */
+    */
-  SX1261(Module* mod)
+    SX1261(Module* mod)
-    : SX1262(mod) {
+      : SX1262(mod) {
-  }
+    }
 
-  int16_t setOutputPower(int8_t power);
+    int16_t setOutputPower(int8_t power);
+
+  private:
+    int16_t setOptimalLowPowerPaConfig(int8_t* inOutPower);
 };
 
 

src/modules/SX1262.cpp

@@ -85,7 +85,7 @@ int16_t SX1262::setFrequency(float freq, bool calibrate) {
 
 int16_t SX1262::setOutputPower(int8_t power) {
   // check allowed power range
-  if (!((power >= -17) && (power <= 22))) {
+  if (!(power >= -17 && power <= 22)) {
     return(ERR_INVALID_OUTPUT_POWER);
   }
 
@@ -96,42 +96,22 @@ int16_t SX1262::setOutputPower(int8_t power) {
     return(state);
   }
 
-  int8_t scaledPower;
+  // this function sets the optimal PA settings 
-  // set PA config for optimal consumption as described in section 13-21 of the datasheet:
+  // and scales our requested power based
-  // the final column of Table 13-21 suggests that the value passed in SetTxParams 
+  state = SX126x::setOptimalHiPowerPaConfig(&power);
-  // is actually scaled depending on the parameters of setPaConfig.
-  // Testing confirms this is approximately right
-  if (power >= 21) {
-    state = SX126x::setPaConfig(0x04, SX126X_PA_CONFIG_SX1262, SX126X_PA_CONFIG_HP_MAX/*0x07*/);
-    scaledPower = power;
-  }
-  else if (power >= 18) {
-    state = SX126x::setPaConfig(0x03, SX126X_PA_CONFIG_SX1262, 0x05);
-    scaledPower = power + 2;
-  }
-  else if (power >= 15) {
-    state = SX126x::setPaConfig(0x02, SX126X_PA_CONFIG_SX1262, 0x03);
-    scaledPower = power + 5;
-  }
-  else {
-    state = SX126x::setPaConfig(0x02, SX126X_PA_CONFIG_SX1262, 0x02);
-    scaledPower = power + 8;
-  }
-  if (state != ERR_NONE) {
-    return(state);
-  }
-  // TODO investigate if better power efficiency can be achieved using undocumented even lower settings
-
-  // note that we set SX126X_PA_CONFIG_SX1262 for all power levels - setting SX126X_PA_CONFIG_SX1261 causes no output (on the nameless module I have).
 
   // set output power
   // TODO power ramp time configuration
-  state = SX126x::setTxParams(scaledPower);
+  if (state == ERR_NONE) {
-  if (state != ERR_NONE) {
+    state = SX126x::setTxParams(power);
-    return state;
   }
 
-
   // restore OCP configuration
-  return(writeRegister(SX126X_REG_OCP_CONFIGURATION, &ocp, 1));
+  int16_t state2 = writeRegister(SX126X_REG_OCP_CONFIGURATION, &ocp, 1);
+  
+  if (state != ERR_NONE) {
+    return state;
+  } else {
+    return state2;
+  }
 }

src/modules/SX1262.h

@@ -6,8 +6,6 @@
 #include "SX126x.h"
 
 //SX126X_CMD_SET_PA_CONFIG
-#define SX126X_PA_CONFIG_SX1261                       0x01
-#define SX126X_PA_CONFIG_SX1262                       0x00
 
 /*!
   \class SX1262

src/modules/SX1268.cpp

@@ -78,6 +78,9 @@ int16_t SX1268::setFrequency(float freq, bool calibrate) {
 
 int16_t SX1268::setOutputPower(int8_t power) {
   // check allowed power range
+  // TODO with optimal PA config
+  // it's likely possible this could be expanded to go down to -17 just like for SX1262.
+  // but the datasheet doesn't explicitly state that and I don't have SX1268 unit to test with
   if(!((power >= -9) && (power <= 22))) {
     return(ERR_INVALID_OUTPUT_POWER);
   }
@@ -89,13 +92,21 @@ int16_t SX1268::setOutputPower(int8_t power) {
     return(state);
   }
 
-  // enable high power PA
+  // enable optimal PA
-  SX126x::setPaConfig(0x04, SX126X_PA_CONFIG_SX1268);
+  state = SX126x::setOptimalHiPowerPaConfig(&power);
 
   // set output power
   // TODO power ramp time configuration
-  SX126x::setTxParams(power);
+  if (state == ERR_NONE) {
+    state = SX126x::setTxParams(power);
+  }
 
   // restore OCP configuration
-  return(writeRegister(SX126X_REG_OCP_CONFIGURATION, &ocp, 1));
+  int16_t state2 = writeRegister(SX126X_REG_OCP_CONFIGURATION, &ocp, 1);
+
+  if (state != ERR_NONE) {
+    return state;
+  } else {
+    return state2;
+  }
 }

src/modules/SX126x.cpp

@@ -1127,6 +1127,32 @@ int16_t SX126x::setTxParams(uint8_t power, uint8_t rampTime) {
   return(SPIwriteCommand(SX126X_CMD_SET_TX_PARAMS, data, 2));
 }
 
+// set PA config for optimal consumption as described in section 13-21 of the datasheet:
+// the final column of Table 13-21 suggests that the value passed in SetTxParams 
+// is actually scaled depending on the parameters of setPaConfig.
+// Testing confirms this is approximately right
+int16_t SX126x::setOptimalHiPowerPaConfig(int8_t* inOutPower)
+{
+  int16_t state;
+  if (*inOutPower >= 21) {
+    state = SX126x::setPaConfig(0x04, SX126X_PA_CONFIG_SX1262_8, SX126X_PA_CONFIG_HP_MAX/*0x07*/);
+  }
+  else if (*inOutPower >= 18) {
+    state = SX126x::setPaConfig(0x03, SX126X_PA_CONFIG_SX1262_8, 0x05);
+    *inOutPower += 2;
+  }
+  else if (*inOutPower >= 15) {
+    state = SX126x::setPaConfig(0x02, SX126X_PA_CONFIG_SX1262_8, 0x03);
+    *inOutPower += 5;
+  }
+  else {
+    state = SX126x::setPaConfig(0x02, SX126X_PA_CONFIG_SX1262_8, 0x02);
+    *inOutPower += 8;
+  }
+  // TODO investigate if better power efficiency can be achieved using undocumented even lower settings
+  return state;
+}
+
 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) {

src/modules/SX126x.h

@@ -152,6 +152,8 @@
 //SX126X_CMD_SET_PA_CONFIG
 #define SX126X_PA_CONFIG_HP_MAX                       0x07
 #define SX126X_PA_CONFIG_PA_LUT                       0x01
+#define SX126X_PA_CONFIG_SX1261                       0x01
+#define SX126X_PA_CONFIG_SX1262_8                     0x00
 
 //SX126X_CMD_SET_RX_TX_FALLBACK_MODE
 #define SX126X_RX_TX_FALLBACK_MODE_FS                 0x40        //  7     0     after Rx/Tx go to: FS mode
@@ -739,6 +741,7 @@ 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 setOptimalHiPowerPaConfig(int8_t* inOutPower);
     int16_t setModulationParams(uint8_t sf, uint8_t bw, uint8_t cr, uint8_t ldro = 0xFF);
     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 = 0xFF, uint8_t headerType = SX126X_LORA_HEADER_EXPLICIT, uint8_t invertIQ = SX126X_LORA_IQ_STANDARD);