[SX126x] Add support for coding rate 4/4

src/modules/LLCC68/LLCC68.cpp

@@ -151,7 +151,7 @@ int16_t LLCC68::checkDataRate(DataRate_t dr) {
 
   } else if(modem == RADIOLIB_SX126X_PACKET_TYPE_LORA) {
     RADIOLIB_CHECK_RANGE(dr.lora.bandwidth, 100.0f, 510.0f, RADIOLIB_ERR_INVALID_BANDWIDTH);
-    RADIOLIB_CHECK_RANGE(dr.lora.codingRate, 5, 8, RADIOLIB_ERR_INVALID_CODING_RATE);
+    RADIOLIB_CHECK_RANGE(dr.lora.codingRate, 4, 8, RADIOLIB_ERR_INVALID_CODING_RATE);
     uint8_t bw_div2 = dr.lora.bandwidth / 2 + 0.01f;
     switch (bw_div2)  {
       case 62: // 125.0:

src/modules/LLCC68/LLCC68.h

@@ -29,7 +29,8 @@ class LLCC68: public SX1262 {
       \param freq Carrier frequency in MHz. Defaults to 434.0 MHz.
       \param bw LoRa bandwidth in kHz. Defaults to 125.0 kHz.
       \param sf LoRa spreading factor. Defaults to 9.
-      \param cr LoRa coding rate denominator. Defaults to 7 (coding rate 4/7).
+      \param cr LoRa coding rate denominator. Defaults to 7 (coding rate 4/7). Allowed values range from 4 to 8. Note that a value of 4 means no coding,
+      is undocumented and not recommended without your own FEC.
       \param syncWord 1-byte LoRa sync word. Defaults to RADIOLIB_SX126X_SYNC_WORD_PRIVATE (0x12).
       \param pwr Output power in dBm. Defaults to 10 dBm.
       \param preambleLength LoRa preamble length in symbols. Defaults to 8 symbols.

src/modules/SX126x/SX1262.h

@@ -34,7 +34,8 @@ class SX1262: public SX126x {
       \param freq Carrier frequency in MHz. Defaults to 434.0 MHz.
       \param bw LoRa bandwidth in kHz. Defaults to 125.0 kHz.
       \param sf LoRa spreading factor. Defaults to 9.
-      \param cr LoRa coding rate denominator. Defaults to 7 (coding rate 4/7).
+      \param cr LoRa coding rate denominator. Defaults to 7 (coding rate 4/7). Allowed values range from 4 to 8. Note that a value of 4 means no coding,
+      is undocumented and not recommended without your own FEC.
       \param syncWord 1-byte LoRa sync word. Defaults to RADIOLIB_SX126X_SYNC_WORD_PRIVATE (0x12).
       \param power Output power in dBm. Defaults to 10 dBm.
       \param preambleLength LoRa preamble length in symbols. Defaults to 8 symbols.

src/modules/SX126x/SX1268.h

@@ -33,7 +33,8 @@ class SX1268: public SX126x {
       \param freq Carrier frequency in MHz. Defaults to 434.0 MHz.
       \param bw LoRa bandwidth in kHz. Defaults to 125.0 kHz.
       \param sf LoRa spreading factor. Defaults to 9.
-      \param cr LoRa coding rate denominator. Defaults to 7 (coding rate 4/7).
+      \param cr LoRa coding rate denominator. Defaults to 7 (coding rate 4/7). Allowed values range from 4 to 8. 
+      Note that a value of 4 means no coding, is undocumented and not recommended without your own FEC.
       \param syncWord 1-byte LoRa sync word. Defaults to RADIOLIB_SX126X_SYNC_WORD_PRIVATE (0x12).
       \param power Output power in dBm. Defaults to 10 dBm.
       \param preambleLength LoRa preamble length in symbols. Defaults to 8 symbols.

src/modules/SX126x/SX126x.cpp

@@ -801,7 +801,7 @@ int16_t SX126x::setCodingRate(uint8_t cr) {
     return(RADIOLIB_ERR_WRONG_MODEM);
   }
 
-  RADIOLIB_CHECK_RANGE(cr, 5, 8, RADIOLIB_ERR_INVALID_CODING_RATE);
+  RADIOLIB_CHECK_RANGE(cr, 4, 8, RADIOLIB_ERR_INVALID_CODING_RATE);
 
   // update modulation parameters
   this->codingRate = cr - 4;
@@ -958,7 +958,7 @@ int16_t SX126x::checkDataRate(DataRate_t dr) {
   } else if(modem == RADIOLIB_SX126X_PACKET_TYPE_LORA) {
     RADIOLIB_CHECK_RANGE(dr.lora.spreadingFactor, 5, 12, RADIOLIB_ERR_INVALID_SPREADING_FACTOR);
     RADIOLIB_CHECK_RANGE(dr.lora.bandwidth, 0.0f, 510.0f, RADIOLIB_ERR_INVALID_BANDWIDTH);
-    RADIOLIB_CHECK_RANGE(dr.lora.codingRate, 5, 8, RADIOLIB_ERR_INVALID_CODING_RATE);
+    RADIOLIB_CHECK_RANGE(dr.lora.codingRate, 4, 8, RADIOLIB_ERR_INVALID_CODING_RATE);
     return(RADIOLIB_ERR_NONE);
   
   }

src/modules/SX126x/SX126x.h

@@ -501,7 +501,8 @@ class SX126x: public PhysicalLayer {
 
     /*!
       \brief Initialization method for LoRa modem.
-      \param cr LoRa coding rate denominator. Allowed values range from 5 to 8.
+      \param cr LoRa coding rate denominator. Allowed values range from 4 to 8. Note that a value of 4 means no coding,
+      is undocumented and not recommended without your own FEC.
       \param syncWord 1-byte LoRa sync word.
       \param preambleLength LoRa preamble length in symbols. Allowed values range from 1 to 65535.
       \param tcxoVoltage TCXO reference voltage to be set on DIO3. Defaults to 1.6 V, set to 0 to skip.
@@ -774,7 +775,8 @@ class SX126x: public PhysicalLayer {
     virtual int16_t setSpreadingFactor(uint8_t sf);
 
     /*!
-      \brief Sets LoRa coding rate denominator. Allowed values range from 5 to 8.
+      \brief Sets LoRa coding rate denominator. Allowed values range from 4 to 8. Note that a value of 4 means no coding, 
+      is undocumented and not recommended without your own FEC.
       \param cr LoRa coding rate denominator to be set.
       \returns \ref status_codes
     */