SX1262 with Channel Activity Detection-Wake-on-Radio-Deep Sleep

CAD_WOR_Deep_SLeep.ino

#define EoRa_PI_V1
#include <RadioLib.h>
#include <boards.h>
#include <SPI.h>
#include "driver/rtc_io.h"

// --- Pin Definitions 
//Using Ebyte's EoRa-S3-900TB Configuration files

#define WAKEUP_PIN GPIO_NUM_16

const float radioFreq = 915.0;     // MHz
const float bandWidth = 125.0;     // kHz
const uint8_t spreadingFactor = 7;
const uint8_t codingRate = 7;
const uint8_t syncWord = RADIOLIB_SX126X_SYNC_WORD_PRIVATE;

SX1262 radio = new Module(RADIO_CS_PIN, RADIO_DIO1_PIN, RADIO_RST_PIN, RADIO_BUSY_PIN);

// flag to indicate that a packet was detected or CAD timed out
volatile bool scanFlag = 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!
#if defined(ESP8266) || defined(ESP32)
  ICACHE_RAM_ATTR
#endif
void setFlag(void) {
  // something happened, set the flag
  scanFlag = true;
}

void setupLoRa() {
  SPI.begin(RADIO_SCLK_PIN, RADIO_MISO_PIN, RADIO_MOSI_PIN, RADIO_CS_PIN);

  radio.standby();
  delay(50);

  radio.resetOnStartup = true;
  delay(50);
  radio.tcxoVoltage = 1.6; // Crucial 1.6V reference for Ebyte modules

  int state = radio.begin(
    radioFreq,
    125.0,
    7,
    7,
    RADIOLIB_SX126X_SYNC_WORD_PRIVATE,
    2,
    5000, // <--- SET PREAMBLE TO 5000 TO MATCH TRANSMITTER
    1.6,
    false
  );

  if (state == RADIOLIB_ERR_NONE) {
    radio.setRegulatorDCDC();
    // Force explicit 5000 symbol preamble configuration
    radio.setPreambleLength(5000); 
    Serial.println(F("[SX1262] Battery Receiver Initialized with 5000-symbol Preamble."));
  } else {
    Serial.printf("[SX1262] Initialization failed, code %d\n", state);
  }
}

// --- Your 10-Pass Diagnostic Logic repurposed as a Filter ---
bool verifySignalWithBusyLoop(int totalPasses = 10, int requiredHits = 3) {
  Serial.println(F("\n--- [WAKE DIAGNOSTIC & MULTI-SCAN START] ---"));
  
  // 1. Verify Sleep Wakeup Reason
  esp_sleep_wakeup_cause_t wakeup_reason = esp_sleep_get_wakeup_cause();
  Serial.printf("  Wakeup Cause Code: %d ", wakeup_reason);
  if (wakeup_reason == ESP_SLEEP_WAKEUP_EXT0) {
    Serial.println(F("(ESP_SLEEP_WAKEUP_EXT0 - DIO1 High)"));
  } else {
    Serial.println(F("(Other Wakeup Reason / Cold Boot)"));
  }

  // 2. Read Physical Pins at Boot
  int dio1State = digitalRead(WAKEUP_PIN);
  int busyState = digitalRead(RADIO_BUSY_PIN);
  Serial.printf("  Pin Levels at Boot -> DIO1 (GPIO %d): %d | BUSY (GPIO %d): %d\n", 
                RADIO_DIO1_PIN, dio1State, RADIO_BUSY_PIN, busyState);

  // 3. Query Radio Internal IRQ Flags
  uint16_t irqFlags = radio.getIrqFlags();
  Serial.printf("  SX1262 Internal IRQ Register: 0x%04X\n", irqFlags);
  if (irqFlags & RADIOLIB_SX126X_IRQ_CAD_DETECTED) {
    Serial.println(F("  [IRQ CHECK] -> RADIOLIB_SX126X_IRQ_CAD_DETECTED is SET!"));
  }
  if (irqFlags & RADIOLIB_SX126X_IRQ_HEADER_VALID) {
    Serial.println(F("  [IRQ CHECK] -> RADIOLIB_SX126X_IRQ_HEADER_VALID is SET!"));
  }

  //esp_sleep_wakeup_cause_t wakeup_reason = esp_sleep_get_wakeup_cause();

  if (wakeup_reason == ESP_SLEEP_WAKEUP_EXT0) {
    Serial.println("Woke from hub WOR -- reading and sending BME280 data");
    digitalWrite(BOARD_LED, LED_ON);
  }  

  return false;
}

void enterLowPowerWOR() {

  radio.clearIrqFlags(RADIOLIB_SX126X_IRQ_ALL);

  int state = radio.startReceiveDutyCycleAuto(
      5000,
      0,
      RADIOLIB_SX126X_IRQ_PREAMBLE_DETECTED |
      RADIOLIB_SX126X_IRQ_HEADER_VALID |
      RADIOLIB_SX126X_IRQ_RX_DONE,

      RADIOLIB_SX126X_IRQ_PREAMBLE_DETECTED |
      RADIOLIB_SX126X_IRQ_HEADER_VALID |
      RADIOLIB_SX126X_IRQ_RX_DONE
  );


  if (state != RADIOLIB_ERR_NONE) {
    Serial.printf("[SX1262] DutyCycleAuto failed, code: %d\n", state);
    return;
  }


  // DIO1 = GPIO16, already defined by EoRa board file
  pinMode(WAKEUP_PIN, INPUT);


  // EXT0 is level triggered
  // SX1262 DIO1 goes HIGH on interrupt
  esp_sleep_enable_ext0_wakeup(WAKEUP_PIN, 1);


  Serial.printf("DIO1 GPIO %d before sleep = %d\n",
                WAKEUP_PIN,
                digitalRead(WAKEUP_PIN));

  Serial.println(F(
    "=== SX1262 WOR armed - ESP32-S3 entering deep sleep ==="
  ));

  Serial.flush();

  esp_deep_sleep_start();
}
void setup() {

  initBoard();
  delay(1500);

  Serial.begin(115200);
  delay(1500); // Give CDC Serial monitor time to connect

  Serial.println(F("\n=============================================="));
  Serial.println(F("--- ESP32-S3 WOR NODE (BOOT DIAGNOSTIC) ---"));

   // 1. Initialize Radio SPI & SX1262
  setupLoRa();

  // 2. ALWAYS run diagnostic on boot to verify pin states and test CAD
  Serial.println(F("Executing mandatory boot-up radio diagnostic..."));
  verifySignalWithBusyLoop(10, 3);

  // 3. Enter WOR Sleep
  enterLowPowerWOR();
}

void loop() {
  // Unused
}