NRF52 Repeater Powersaving

examples/simple_repeater/main.cpp

@@ -20,8 +20,12 @@ void halt() {
 static char command[160];
 
 // For power saving
+constexpr unsigned long ACTIVE_TIME_SEC_INUSE = 2 * 60; // 2 minutes
+constexpr unsigned long ACTIVE_TIME_SEC_IDLE = 5;       // 5 seconds
+constexpr unsigned long IDLE_PERIOD_SEC = 30 * 60;      // 30 minutes
+
 unsigned long lastActive = 0; // mark last active time
-unsigned long nextSleepinSecs = 120; // next sleep in seconds. The first sleep (if enabled) is after 2 minutes from boot
+unsigned long nextSleepinSecs = ACTIVE_TIME_SEC_INUSE; // next sleep in seconds
 
 void setup() {
   Serial.begin(115200);
@@ -110,6 +114,8 @@ void loop() {
     Serial.print('\n');
     command[len - 1] = 0;  // replace newline with C string null terminator
     char reply[160];
+    lastActive = millis();
+    nextSleepinSecs = ACTIVE_TIME_SEC_INUSE;
     the_mesh.handleCommand(0, command, reply);  // NOTE: there is no sender_timestamp via serial!
     if (reply[0]) {
       Serial.print("  -> "); Serial.println(reply);
@@ -125,14 +131,14 @@ void loop() {
 #endif
   rtc_clock.tick();
 
-  if (the_mesh.getNodePrefs()->powersaving_enabled &&                     // To check if power saving is enabled
+  if (the_mesh.getNodePrefs()->powersaving_enabled &&
       the_mesh.millisHasNowPassed(lastActive + nextSleepinSecs * 1000)) { // To check if it is time to sleep
     if (!the_mesh.hasPendingWork()) { // No pending work. Safe to sleep
-      board.sleep(1800);             // To sleep. Wake up after 30 minutes or when receiving a LoRa packet
+      board.sleep(IDLE_PERIOD_SEC);   // To sleep. Wake up after 30 minutes or when receiving a LoRa packet
       lastActive = millis();
-      nextSleepinSecs = 5;  // Default: To work for 5s and sleep again
+      nextSleepinSecs = ACTIVE_TIME_SEC_IDLE; // Default: To work for 5s and sleep again
     } else {
-      nextSleepinSecs += 5; // When there is pending work, to work another 5s
+      nextSleepinSecs += ACTIVE_TIME_SEC_IDLE; // When there is pending work, to work another 5s
     }
   }
 }

src/helpers/NRF52Board.cpp

@@ -4,6 +4,7 @@
 #include <bluefruit.h>
 
 static BLEDfu bledfu;
+static SoftwareTimer sleep_timer;
 
 static void connect_callback(uint16_t conn_handle) {
   (void)conn_handle;
@@ -17,10 +18,20 @@ static void disconnect_callback(uint16_t conn_handle, uint8_t reason) {
   MESH_DEBUG_PRINTLN("BLE client disconnected");
 }
 
+static void sleep_timer_callback(TimerHandle_t xTimerID) {
+  resumeLoop();
+}
+
 void NRF52Board::begin() {
   startup_reason = BD_STARTUP_NORMAL;
 }
 
+void NRF52Board::sleep(uint32_t secs) {
+  sleep_timer.begin(secs * 1000, sleep_timer_callback, NULL, false);
+  sleep_timer.start();
+  suspendLoop();
+}
+
 void NRF52BoardDCDC::begin() {
   NRF52Board::begin();
 

src/helpers/NRF52Board.h

@@ -14,6 +14,7 @@ class NRF52Board : public mesh::MainBoard {
   virtual uint8_t getStartupReason() const override { return startup_reason; }
   virtual float getMCUTemperature() override;
   virtual void reboot() override { NVIC_SystemReset(); }
+  virtual void sleep(uint32_t secs);
 };
 
 /*

src/helpers/radiolib/RadioLibWrappers.cpp

@@ -22,6 +22,11 @@ static
 void setFlag(void) {
   // we sent a packet, set the flag
   state |= STATE_INT_READY;
+
+#ifdef NRF52_PLATFORM
+  // NRF52 uses suspendLoop() for powersaving, resume on RX interrupt here
+  if (state & STATE_RX) resumeLoop();
+#endif
 }
 
 void RadioLibWrapper::begin() {

variants/rak4631/RAK4631Board.h

@@ -7,7 +7,7 @@
 // LoRa radio module pins for RAK4631
 #define  P_LORA_DIO_1   47
 #define  P_LORA_NSS     42
-#define  P_LORA_RESET  RADIOLIB_NC   // 38
+#define P_LORA_RESET               38
 #define  P_LORA_BUSY    46
 #define  P_LORA_SCLK    43
 #define  P_LORA_MISO    45