nRF52840 Watchdog

examples/companion_radio/main.cpp

@@ -228,4 +228,5 @@ void loop() {
   ui_task.loop();
 #endif
   rtc_clock.tick();
+  board.tick();
 }

examples/simple_repeater/main.cpp

@@ -124,6 +124,7 @@ void loop() {
   ui_task.loop();
 #endif
   rtc_clock.tick();
+  board.tick();
 
   if (the_mesh.getNodePrefs()->powersaving_enabled &&                     // To check if power saving is enabled
       the_mesh.millisHasNowPassed(lastActive + nextSleepinSecs * 1000)) { // To check if it is time to sleep

examples/simple_room_server/main.cpp

@@ -111,4 +111,5 @@ void loop() {
   ui_task.loop();
 #endif
   rtc_clock.tick();
+  board.tick();
 }

examples/simple_secure_chat/main.cpp

@@ -588,4 +588,5 @@ void setup() {
 void loop() {
   the_mesh.loop();
   rtc_clock.tick();
+  board.tick();
 }

examples/simple_sensor/main.cpp

@@ -145,4 +145,5 @@ void loop() {
   ui_task.loop();
 #endif
   rtc_clock.tick();
+  board.tick();
 }

platformio.ini

@@ -86,6 +86,8 @@ build_flags = ${arduino_base.build_flags}
   -D NRF52_PLATFORM
   -D LFS_NO_ASSERT=1
   -D EXTRAFS=1
+build_src_filter = ${arduino_base.build_src_filter}
+  +<helpers/nrf52/Watchdog.cpp>
 lib_deps =
   ${arduino_base.lib_deps}
   https://github.com/oltaco/CustomLFS @ 0.2.1

src/MeshCore.h

@@ -56,6 +56,7 @@ class MainBoard {
   virtual void setGpio(uint32_t values) {}
   virtual uint8_t getStartupReason() const = 0;
   virtual bool startOTAUpdate(const char* id, char reply[]) { return false; }   // not supported
+  virtual void tick() { }   // called each loop iteration for board-specific periodic tasks
 };
 
 /**

src/helpers/CommonCLI.cpp

@@ -4,6 +4,10 @@
 #include "AdvertDataHelpers.h"
 #include <RTClib.h>
 
+#if defined(NRF52_PLATFORM) && defined(ENABLE_WATCHDOG)
+#include "nrf52/Watchdog.h"
+#endif
+
 // Believe it or not, this std C function is busted on some platforms!
 static uint32_t _atoi(const char* sp) {
   uint32_t n = 0;
@@ -364,6 +368,10 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
         } else {
           sprintf(reply, "> %.3f", adc_mult);
         }
+#if defined(NRF52_PLATFORM) && defined(ENABLE_WATCHDOG)
+      } else if (memcmp(config, "wdt.status", 10) == 0) {
+        sprintf(reply, "> %s", nrf52::Watchdog::isEnabled() ? "enabled" : "disabled");
+#endif
       } else {
         sprintf(reply, "??: %s", config);
       }

src/helpers/NRF52Board.cpp

@@ -3,6 +3,10 @@
 
 #include <bluefruit.h>
 
+#ifdef ENABLE_WATCHDOG
+#include "nrf52/Watchdog.h"
+#endif
+
 static BLEDfu bledfu;
 
 static void connect_callback(uint16_t conn_handle) {
@@ -19,6 +23,15 @@ static void disconnect_callback(uint16_t conn_handle, uint8_t reason) {
 
 void NRF52Board::begin() {
   startup_reason = BD_STARTUP_NORMAL;
+#ifdef ENABLE_WATCHDOG
+  nrf52::Watchdog::begin();
+#endif
+}
+
+void NRF52Board::tick() {
+#ifdef ENABLE_WATCHDOG
+  nrf52::Watchdog::feed();
+#endif
 }
 
 void NRF52BoardDCDC::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 tick() override;
 };
 
 /*

src/helpers/nrf52/Watchdog.cpp

@@ -0,0 +1,50 @@
+#ifdef NRF52_PLATFORM
+
+#include "Watchdog.h"
+#include <nrf.h>
+
+// WDT reload request magic value
+#define WDT_RR_VALUE 0x6E524635UL
+
+// 30 second timeout at 32.768kHz clock
+// CRV = timeout_seconds * 32768
+#define WDT_TIMEOUT_SECONDS 30
+#define WDT_CRV_VALUE (WDT_TIMEOUT_SECONDS * 32768UL)
+
+namespace nrf52 {
+
+// Init watchdog timer - return true if success, false if already running
+bool Watchdog::begin() {
+    // Check if already running - WDT cannot be reconfigured once started
+    if (NRF_WDT->RUNSTATUS) {
+        return false;
+    }
+    // Configure WDT to pause during sleep and halt modes
+    NRF_WDT->CONFIG = (WDT_CONFIG_SLEEP_Pause << WDT_CONFIG_SLEEP_Pos) |
+                      (WDT_CONFIG_HALT_Pause << WDT_CONFIG_HALT_Pos);
+
+    // Set timeout value (30 seconds)
+    NRF_WDT->CRV = WDT_CRV_VALUE;
+
+    // Enable reload request register 0
+    NRF_WDT->RREN = WDT_RREN_RR0_Enabled << WDT_RREN_RR0_Pos;
+
+    // Start the watchdog
+    NRF_WDT->TASKS_START = 1;
+
+    return true;
+}
+
+// Feed watchdog timer within timout interval to prevent board reset
+void Watchdog::feed() {
+    // Write magic value to reload request register 0
+    NRF_WDT->RR[0] = WDT_RR_VALUE;
+}
+
+bool Watchdog::isEnabled() {
+    return NRF_WDT->RUNSTATUS != 0;
+}
+
+} // namespace nrf52
+
+#endif // NRF52_PLATFORM

src/helpers/nrf52/Watchdog.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#ifdef NRF52_PLATFORM
+
+#include <stdint.h>
+
+namespace nrf52 {
+
+class Watchdog {
+public:
+    static bool begin();
+    static void feed();
+    static bool isEnabled();
+};
+
+} // namespace nrf52
+
+#endif // NRF52_PLATFORM

variants/heltec_t114/platformio.ini

@@ -34,6 +34,7 @@ build_flags = ${nrf52_base.build_flags}
   -D PIN_GPS_EN=21
   -D PIN_GPS_RESET=38
   -D PIN_GPS_RESET_ACTIVE=LOW
+  -D ENABLE_WATCHDOG
 build_src_filter = ${nrf52_base.build_src_filter}
   +<helpers/*.cpp>
   +<../variants/heltec_t114>