[SX126x] Implemented getPacketLength

examples/SX126x/SX126x_Transmit/SX126x_Transmit.ino

@@ -56,20 +56,22 @@ void setup() {
   //       control must be enabled by calling
   //       setTCXO() and specifying the reference
   //       voltage.
+  
   /*
-  Serial.print(F("[SX1262] Setting TCXO reference ... "));
+    Serial.print(F("[SX1262] Setting TCXO reference ... "));
-  // enable TCXO
+    // enable TCXO
-  // reference voltage:           1.6 V
+    // reference voltage:           1.6 V
-  // timeout:                     5000 us
+    // timeout:                     5000 us
-  state = lora.setTCXO(1.6);
+    state = lora.setTCXO(1.6);
-  if (state == ERR_NONE) {
+    if (state == ERR_NONE) {
-    Serial.println(F("success!"));
+      Serial.println(F("success!"));
-  } else {
+    } else {
-    Serial.print(F("failed, code "));
+      Serial.print(F("failed, code "));
-    Serial.println(state);
+      Serial.println(state);
-    while (true);
+      while (true);
-  }
+    }
   */
+  
 }
 
 void loop() {
@@ -90,7 +92,7 @@ void loop() {
 
   if (state == ERR_NONE) {
     // the packet was successfully transmitted
-    Serial.println(F(" success!"));
+    Serial.println(F("success!"));
 
     // print measured data rate
     Serial.print(F("[SX1262] Datarate:\t"));
@@ -99,11 +101,11 @@ void loop() {
 
   } else if (state == ERR_PACKET_TOO_LONG) {
     // the supplied packet was longer than 256 bytes
-    Serial.println(F(" too long!"));
+    Serial.println(F("too long!"));
 
   } else if (state == ERR_TX_TIMEOUT) {
     // timeout occured while transmitting packet
-    Serial.println(F(" timeout!"));
+    Serial.println(F("timeout!"));
 
   } else {
     // some other error occurred

src/modules/SX126x.cpp

@@ -1,6 +1,6 @@
 #include "SX126x.h"
 
-SX126x::SX126x(Module* mod) : PhysicalLayer(SX126X_CRYSTAL_FREQ, SX126X_DIV_EXPONENT) {
+SX126x::SX126x(Module* mod) : PhysicalLayer(SX126X_CRYSTAL_FREQ, SX126X_DIV_EXPONENT, SX126X_MAX_PACKET_LENGTH) {
   _mod = mod;
 }
 
@@ -137,7 +137,7 @@ int16_t SX126x::transmit(uint8_t* data, size_t len, uint8_t addr) {
   }
 
   // check packet length
-  if(len >= 256) {
+  if(len > SX126X_MAX_PACKET_LENGTH) {
     return(ERR_PACKET_TOO_LONG);
   }
 
@@ -359,7 +359,7 @@ int16_t SX126x::startTransmit(uint8_t* data, size_t len, uint8_t addr) {
   (void)addr;
 
   // check packet length
-  if(len >= 256) {
+  if(len > SX126X_MAX_PACKET_LENGTH) {
     return(ERR_PACKET_TOO_LONG);
   }
 
@@ -447,22 +447,10 @@ int16_t SX126x::readData(uint8_t* data, size_t len) {
   }
 
   // get packet length
-  uint8_t rxBufStatus[2];
+  size_t length = getPacketLength();
-  int16_t state = SPIreadCommand(SX126X_CMD_GET_RX_BUFFER_STATUS, rxBufStatus, 2);
-  if(state != ERR_NONE) {
-    return(state);
-  }
-
-  size_t length = rxBufStatus[0];
 
   // read packet data
-  if(len == 0) {
+  int16_t state = readBuffer(data, length);
-    // argument 'len' equal to zero indicates String call, which means dynamically allocated data array
-    // dispose of the original and create a new one
-    delete[] data;
-    data = new uint8_t[length + 1];
-  }
-  state = readBuffer(data, length);
   if(state != ERR_NONE) {
     return(state);
   }
@@ -872,6 +860,13 @@ float SX126x::getSNR() {
   return(snrPkt/4.0);
 }
 
+size_t SX126x::getPacketLength(bool update) {
+  (void)update;
+  uint8_t rxBufStatus[2];
+  SPIreadCommand(SX126X_CMD_GET_RX_BUFFER_STATUS, rxBufStatus, 2);
+  return((size_t)rxBufStatus[0]);
+}
+
 int16_t SX126x::setTCXO(float voltage, uint32_t timeout) {
   // set mode to standby
   standby();

src/modules/SX126x.h

@@ -9,6 +9,7 @@
 // SX126X physical layer properties
 #define SX126X_CRYSTAL_FREQ                           32.0
 #define SX126X_DIV_EXPONENT                           25
+#define SX126X_MAX_PACKET_LENGTH                      255
 
 // SX126X SPI commands
 // operational modes commands
@@ -685,6 +686,15 @@ class SX126x: public PhysicalLayer {
     */
     float getSNR();
 
+     /*!
+      \brief Query modem for the packet length of received payload.
+
+      \param update Update received packet length. Will return cached value when set to false.
+
+      \returns Length of last received packet in bytes.
+    */
+    size_t getPacketLength(bool update = true);
+
   protected:
     // SX1276x SPI command implementations
     int16_t setTx(uint32_t timeout = 0);