NRF52 Repeater Powersaving

examples/simple_repeater/MyMesh.cpp

@@ -1197,5 +1197,5 @@ void MyMesh::loop() {
 
 // To check if there is pending work
 bool MyMesh::hasPendingWork() const {
-  return _mgr->getOutboundCount(0xFFFFFFFF) > 0;
+  return (_mgr->getOutboundCount(0xFFFFFFFF) > 0) || !radio_driver.isInRecvMode();
 }

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.enterSleep(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/MeshCore.h

@@ -41,6 +41,10 @@ namespace mesh {
 #define  BD_STARTUP_RX_PACKET  1
 
 class MainBoard {
+protected:
+  volatile bool prevent_sleep = false;
+  virtual void sleep(uint32_t secs) { /* no op */ }
+
 public:
   virtual uint16_t getBattMilliVolts() = 0;
   virtual float getMCUTemperature() { return NAN; }
@@ -49,9 +53,16 @@ class MainBoard {
   virtual const char* getManufacturerName() const = 0;
   virtual void onBeforeTransmit() { }
   virtual void onAfterTransmit() { }
+  virtual void onRXInterrupt() {}
   virtual void reboot() = 0;
   virtual void powerOff() { /* no op */ }
-  virtual void sleep(uint32_t secs)  { /* no op */ }
+  virtual void enterSleep(uint32_t secs) {
+    if (prevent_sleep) return;
+
+    MESH_DEBUG_PRINTLN("Entering sleep mode, wakeup scheduled in %u seconds", secs);
+    sleep(secs);
+  }
+  virtual void preventSleep() { prevent_sleep = true; }
   virtual uint32_t getGpio() { return 0; }
   virtual void setGpio(uint32_t values) {}
   virtual uint8_t getStartupReason() const = 0;

src/helpers/NRF52Board.cpp

@@ -19,6 +19,18 @@ static void disconnect_callback(uint16_t conn_handle, uint8_t reason) {
 
 void NRF52Board::begin() {
   startup_reason = BD_STARTUP_NORMAL;
+  rx_wait_sem = xSemaphoreCreateBinary();
+  xSemaphoreGive(rx_wait_sem);
+  xSemaphoreTake(rx_wait_sem, portMAX_DELAY);
+}
+
+void NRF52Board::sleep(uint32_t secs) {
+  MESH_DEBUG_PRINTLN("Suspending loop for powersaving, set wakeup timer in %u seconds", secs);
+  xSemaphoreTake(rx_wait_sem, pdMS_TO_TICKS(secs * 1000));
+}
+
+void NRF52Board::onRXInterrupt() {
+  xSemaphoreGive(rx_wait_sem);
 }
 
 void NRF52BoardDCDC::begin() {
@@ -55,6 +67,7 @@ float NRF52Board::getMCUTemperature() {
 }
 
 bool NRF52BoardOTA::startOTAUpdate(const char *id, char reply[]) {
+  preventSleep();
   // Config the peripheral connection with maximum bandwidth
   // more SRAM required by SoftDevice
   // Note: All config***() function must be called before begin()

src/helpers/NRF52Board.h

@@ -6,6 +6,9 @@
 #if defined(NRF52_PLATFORM)
 
 class NRF52Board : public mesh::MainBoard {
+private:
+  SemaphoreHandle_t rx_wait_sem;
+
 protected:
   uint8_t startup_reason;
 
@@ -14,6 +17,8 @@ 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) override;
+  virtual void onRXInterrupt() override;
 };
 
 /*

src/helpers/radiolib/RadioLibWrappers.cpp

@@ -4,32 +4,36 @@
 
 #define STATE_IDLE       0
 #define STATE_RX         1
-#define STATE_TX_WAIT    3
+#define STATE_TX_WAIT    2
 #define STATE_TX_DONE    4
 #define STATE_INT_READY 16
 
 #define NUM_NOISE_FLOOR_SAMPLES  64
 #define SAMPLING_THRESHOLD  14
 
 static volatile uint8_t state = STATE_IDLE;
+static mesh::MainBoard *board;
 
 // this function is called when a complete packet
 // is transmitted by the module
-static 
+static
 #if defined(ESP8266) || defined(ESP32)
-  ICACHE_RAM_ATTR
+    ICACHE_RAM_ATTR
 #endif
-void setFlag(void) {
+    void radioISR(void) {
   // we sent a packet, set the flag
   state |= STATE_INT_READY;
+
+  if (state & STATE_RX) board->onRXInterrupt();
 }
 
 void RadioLibWrapper::begin() {
-  _radio->setPacketReceivedAction(setFlag);  // this is also SentComplete interrupt
+  board = _board;
+  _radio->setPacketReceivedAction(radioISR); // this is also SentComplete interrupt
   state = STATE_IDLE;
 
   if (_board->getStartupReason() == BD_STARTUP_RX_PACKET) {  // received a LoRa packet (while in deep sleep)
-    setFlag(); // LoRa packet is already received
+    radioISR();                                              // LoRa packet is already received
   }
 
   _noise_floor = 0;

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