[Si443x] Synced parameters of all FSK modules

examples/Si443x/Si443x_Settings/Si443x_Settings.ino

@@ -58,7 +58,8 @@ void setup() {
   // frequency deviation:         60.0 kHz
   // Rx bandwidth:                335.5 kHz
   // output power:                17 dBm
-  state = radio2.begin(868.0, 200.0, 60.0, 335.5, 17);
+  // preamble length:             32 bits
+  state = radio2.begin(868.0, 200.0, 60.0, 335.5, 17, 32);
   if (state == ERR_NONE) {
     Serial.println(F("success!"));
   } else {

src/modules/Si443x/Si4430.cpp

@@ -5,9 +5,9 @@ Si4430::Si4430(Module* mod) : Si4432(mod) {
 
 }
 
-int16_t Si4430::begin(float freq, float br, float freqDev, float rxBw, int8_t power) {
+int16_t Si4430::begin(float freq, float br, float freqDev, float rxBw, int8_t power, uint8_t preambleLen) {
   // execute common part
-  int16_t state = Si443x::begin(br, freqDev, rxBw);
+  int16_t state = Si443x::begin(br, freqDev, rxBw, preambleLen);
   RADIOLIB_ASSERT(state);
 
   // configure publicly accessible settings

src/modules/Si443x/Si4430.h

@@ -40,9 +40,11 @@ class Si4430: public Si4432 {
 
       \param power Transmission output power in dBm. Allowed values range from -8 to 13 dBm in 3 dBm steps.
 
+      \param preambleLen Preamble Length in bits. Defaults to 16 bits.
+
       \returns \ref status_codes
     */
-    int16_t begin(float freq = 434.0, float br = 48.0, float freqDev = 50.0, float rxBw = 181.1, int8_t power = 10);
+    int16_t begin(float freq = 434.0, float br = 48.0, float freqDev = 50.0, float rxBw = 181.1, int8_t power = 10, uint8_t preambleLen = 16);
 
     // configuration methods
 

src/modules/Si443x/Si4431.cpp

@@ -5,9 +5,9 @@ Si4431::Si4431(Module* mod) : Si4432(mod) {
 
 }
 
-int16_t Si4431::begin(float freq, float br, float freqDev, float rxBw, int8_t power) {
+int16_t Si4431::begin(float freq, float br, float freqDev, float rxBw, int8_t power, uint8_t preambleLen) {
   // execute common part
-  int16_t state = Si443x::begin(br, freqDev, rxBw);
+  int16_t state = Si443x::begin(br, freqDev, rxBw, preambleLen);
   RADIOLIB_ASSERT(state);
 
   // configure publicly accessible settings

src/modules/Si443x/Si4431.h

@@ -40,9 +40,11 @@ class Si4431: public Si4432 {
 
       \param power Transmission output power in dBm. Allowed values range from -8 to 13 dBm in 3 dBm steps.
 
+      \param preambleLen Preamble Length in bits. Defaults to 16 bits.
+
       \returns \ref status_codes
     */
-    int16_t begin(float freq = 434.0, float br = 48.0, float freqDev = 50.0, float rxBw = 181.1, int8_t power = 10);
+    int16_t begin(float freq = 434.0, float br = 48.0, float freqDev = 50.0, float rxBw = 181.1, int8_t power = 10, uint8_t preambleLen = 16);
 
     // configuration methods
 

src/modules/Si443x/Si4432.cpp

@@ -5,9 +5,9 @@ Si4432::Si4432(Module* mod) : Si443x(mod) {
 
 }
 
-int16_t Si4432::begin(float freq, float br, float freqDev, float rxBw, int8_t power) {
+int16_t Si4432::begin(float freq, float br, float freqDev, float rxBw, int8_t power, uint8_t preambleLen) {
   // execute common part
-  int16_t state = Si443x::begin(br, freqDev, rxBw);
+  int16_t state = Si443x::begin(br, freqDev, rxBw, preambleLen);
   RADIOLIB_ASSERT(state);
 
   // configure publicly accessible settings

src/modules/Si443x/Si4432.h

@@ -40,9 +40,11 @@ class Si4432: public Si443x {
 
       \param power Transmission output power in dBm. Allowed values range from -1 to 20 dBm in 3 dBm steps.
 
+      \param preambleLen Preamble Length in bits. Defaults to 16 bits.
+
       \returns \ref status_codes
     */
-    int16_t begin(float freq = 434.0, float br = 48.0, float freqDev = 50.0, float rxBw = 181.1, int8_t power = 11);
+    int16_t begin(float freq = 434.0, float br = 48.0, float freqDev = 50.0, float rxBw = 181.1, int8_t power = 10, uint8_t preambleLen = 16);
 
     // configuration methods
 

src/modules/Si443x/Si443x.cpp

@@ -5,7 +5,7 @@ Si443x::Si443x(Module* mod) : PhysicalLayer(SI443X_FREQUENCY_STEP_SIZE, SI443X_M
   _mod = mod;
 }
 
-int16_t Si443x::begin(float br, float freqDev, float rxBw) {
+int16_t Si443x::begin(float br, float freqDev, float rxBw, uint8_t preambleLen) {
   // set module properties
   _mod->init(RADIOLIB_USE_SPI);
   Module::pinMode(_mod->getIrq(), INPUT);
@@ -38,7 +38,10 @@ int16_t Si443x::begin(float br, float freqDev, float rxBw) {
   state = setRxBandwidth(rxBw);
   RADIOLIB_ASSERT(state);
 
-  uint8_t syncWord[] = {0x2D, 0x01};
+  state = setPreambleLength(preambleLen);
+  RADIOLIB_ASSERT(state);
+
+  uint8_t syncWord[] = {0x12, 0xAD};
   state = setSyncWord(syncWord, sizeof(syncWord));
   RADIOLIB_ASSERT(state);
 
@@ -477,6 +480,22 @@ int16_t Si443x::setSyncWord(uint8_t* syncWord, size_t len) {
   return(state);
 }
 
+int16_t Si443x::setPreambleLength(uint8_t preambleLen) {
+  // Si443x configures preamble length in bytes
+  if(preambleLen % 8 != 0) {
+    return(ERR_INVALID_PREAMBLE_LENGTH);
+  }
+
+  // set default preamble length
+  uint8_t preLenBytes = preambleLen / 8;
+  int16_t state = _mod->SPIsetRegValue(SI443X_REG_PREAMBLE_LENGTH, preLenBytes);
+  RADIOLIB_ASSERT(state);
+
+  // set default preamble detection threshold to 50% of preamble length (in units of 4 bits)
+  uint8_t preThreshold = preambleLen / 4;
+  return(_mod->SPIsetRegValue(SI443X_REG_PREAMBLE_DET_CONTROL, preThreshold << 4, 3, 7));
+}
+
 size_t Si443x::getPacketLength(bool update) {
   // TODO variable length mode
   if(!_packetLengthQueried && update) {

src/modules/Si443x/Si443x.h

@@ -579,9 +579,11 @@ class Si443x: public PhysicalLayer {
 
       \param rxBw Receiver bandwidth in kHz.
 
+      \param preambleLen Preamble Length in bits.
+
       \returns \ref status_codes
     */
-    int16_t begin(float br, float freqDev, float rxBw);
+    int16_t begin(float br, float freqDev, float rxBw, uint8_t preambleLen);
 
     /*!
       \brief Reset method. Will reset the chip to the default state using SDN pin.
@@ -735,6 +737,15 @@ class Si443x: public PhysicalLayer {
     */
     int16_t setSyncWord(uint8_t* syncWord, size_t len);
 
+    /*!
+      \brief Sets preamble length.
+
+      \param preambleLen Preamble length to be set (in bits).
+
+      \returns \ref status_codes
+    */
+    int16_t setPreambleLength(uint8_t preambleLen);
+
      /*!
       \brief Query modem for the packet length of received payload.