RadioLib/examples/STM32WLx/STM32WLx_Receive_Interrupt/STM32WLx_Receive_Interrupt.ino

/*
   RadioLib STM32WLx Receive with Interrupts Example

   This example listens for LoRa transmissions and tries to
   receive them. Once a packet is received, an interrupt is
   triggered. To successfully receive data, the following
   settings have to be the same on both transmitter
   and receiver:
    - carrier frequency
    - bandwidth
    - spreading factor
    - coding rate
    - sync word
   
   This example assumes Nucleo WL55JC1 is used. For other Nucleo boards
   or standalone STM32WL, some configuration such as TCXO voltage and
   RF switch control may have to be adjusted.

   For default module settings, see the wiki page
   https://github.com/jgromes/RadioLib/wiki/Default-configuration#sx126x---lora-modem

   For full API reference, see the GitHub Pages
   https://jgromes.github.io/RadioLib/
*/

// include the library
#include <RadioLib.h>

// no need to configure pins, signals are routed to the radio internally
STM32WLx radio = new STM32WLx_Module();

// set RF switch configuration for Nucleo WL55JC1
// NOTE: other boards may be different!
static const uint32_t rfswitch_pins[] =
                         {PC3,  PC4,  PC5};
static const Module::RfSwitchMode_t rfswitch_table[] = {
  {STM32WLx::MODE_IDLE,  {LOW,  LOW,  LOW}},
  {STM32WLx::MODE_RX,    {HIGH, HIGH, LOW}},
  {STM32WLx::MODE_TX_LP, {HIGH, HIGH, HIGH}},
  {STM32WLx::MODE_TX_HP, {HIGH, LOW,  HIGH}},
  END_OF_MODE_TABLE,
};

void setup() {
  Serial.begin(9600);

  // set RF switch control configuration
  // this has to be done prior to calling begin()
  radio.setRfSwitchTable(rfswitch_pins, rfswitch_table);

  // initialize STM32WL with default settings, except frequency
  Serial.print(F("[STM32WL] Initializing ... "));
  int state = radio.begin(868.0);
  if (state == RADIOLIB_ERR_NONE) {
    Serial.println(F("success!"));
  } else {
    Serial.print(F("failed, code "));
    Serial.println(state);
    while (true);
  }

  // set appropriate TCXO voltage for Nucleo WL55JC1
  state = radio.setTCXO(1.7);
  if (state == RADIOLIB_ERR_NONE) {
    Serial.println(F("success!"));
  } else {
    Serial.print(F("failed, code "));
    Serial.println(state);
    while (true);
  }

  // set the function that will be called
  // when new packet is received
  radio.setDio1Action(setFlag);

  // start listening for LoRa packets
  Serial.print(F("[STM32WL] Starting to listen ... "));
  state = radio.startReceive();
  if (state == RADIOLIB_ERR_NONE) {
    Serial.println(F("success!"));
  } else {
    Serial.print(F("failed, code "));
    Serial.println(state);
    while (true);
  }

  // if needed, 'listen' mode can be disabled by calling
  // any of the following methods:
  //
  // radio.standby()
  // radio.sleep()
  // radio.transmit();
  // radio.receive();
  // radio.readData();
  // radio.scanChannel();
}

// flag to indicate that a packet was received
volatile bool receivedFlag = false;

// this function is called when a complete packet
// is received by the module
// IMPORTANT: this function MUST be 'void' type
//            and MUST NOT have any arguments!
void setFlag(void) {
  // we got a packet, set the flag
  receivedFlag = true;
}

void loop() {
  // check if the flag is set
  if(receivedFlag) {
    // reset flag
    receivedFlag = false;

    // you can read received data as an Arduino String
    String str;
    int state = radio.readData(str);

    // you can also read received data as byte array
    /*
      byte byteArr[8];
      int numBytes = radio.getPacketLength();
      int state = radio.readData(byteArr, numBytes);
    */

    if (state == RADIOLIB_ERR_NONE) {
      // packet was successfully received
      Serial.println(F("[STM32WL] Received packet!"));

      // print data of the packet
      Serial.print(F("[STM32WL] Data:\t\t"));
      Serial.println(str);

      // print RSSI (Received Signal Strength Indicator)
      Serial.print(F("[STM32WL] RSSI:\t\t"));
      Serial.print(radio.getRSSI());
      Serial.println(F(" dBm"));

      // print SNR (Signal-to-Noise Ratio)
      Serial.print(F("[STM32WL] SNR:\t\t"));
      Serial.print(radio.getSNR());
      Serial.println(F(" dB"));

    } else if (state == RADIOLIB_ERR_CRC_MISMATCH) {
      // packet was received, but is malformed
      Serial.println(F("CRC error!"));

    } else {
      // some other error occurred
      Serial.print(F("failed, code "));
      Serial.println(state);

    }

    // put module back to listen mode
    radio.startReceive();
  }
}