From 363ac44461a9299c9a43641598c18ba65fb6ffea Mon Sep 17 00:00:00 2001
From: Quency-D <hj_zzns@163.com>
Date: Mon, 27 Apr 2026 15:32:02 +0800
Subject: [PATCH] Fix external watchdog timing around sleep

---
 examples/simple_repeater/main.cpp         | 11 ++++++-----
 src/helpers/ExternalWatchdogManager.h     |  4 ++--
 variants/heltec_mesh_solar/platformio.ini |  4 ++--
 variants/heltec_mesh_solar/target.cpp     | 15 +++++++--------
 4 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/examples/simple_repeater/main.cpp b/examples/simple_repeater/main.cpp
index f636c32a..c4e318d5 100644
--- a/examples/simple_repeater/main.cpp
+++ b/examples/simple_repeater/main.cpp
@@ -164,16 +164,17 @@ void loop() {
   if (the_mesh.getNodePrefs()->powersaving_enabled && !the_mesh.hasPendingWork()) {
 #if defined(NRF52_PLATFORM)
 #ifdef HAS_EXTERNAL_WATCHDOG
-    uint32_t sleep_interval = external_watchdog.getIntervalMs()/1000;
-    board.sleep((sleep_interval > 1800) ? 1800 : sleep_interval);             // To sleep. Wake up after 30 minutes or when receiving a LoRa packet
+    external_watchdog.feed();
+    uint32_t sleep_interval = external_watchdog.getIntervalMs() / 1000;
+    board.sleep((sleep_interval > 1800) ? 1800 : sleep_interval); // nrf ignores seconds param, sleeps whenever possible
 #else
-    board.sleep(1800);             // To sleep. Wake up after 30 minutes or when receiving a LoRa packet
-#endif
     board.sleep(1800); // nrf ignores seconds param, sleeps whenever possible
+#endif
 #else
     if (the_mesh.millisHasNowPassed(lastActive + nextSleepinSecs * 1000)) { // To check if it is time to sleep
 #ifdef HAS_EXTERNAL_WATCHDOG
-      uint32_t sleep_interval = external_watchdog.getIntervalMs()/1000;
+      external_watchdog.feed();
+      uint32_t sleep_interval = external_watchdog.getIntervalMs() / 1000;
       board.sleep((sleep_interval > 1800) ? 1800 : sleep_interval);             // To sleep. Wake up after 30 minutes or when receiving a LoRa packet
 #else
       board.sleep(1800);             // To sleep. Wake up after 30 minutes or when receiving a LoRa packet
diff --git a/src/helpers/ExternalWatchdogManager.h b/src/helpers/ExternalWatchdogManager.h
index 9ef8abaa..cb4f4923 100644
--- a/src/helpers/ExternalWatchdogManager.h
+++ b/src/helpers/ExternalWatchdogManager.h
@@ -2,9 +2,9 @@
 
 class ExternalWatchdogManager {
 protected:
-  unsigned long next_feed_watchdog;
+  unsigned long last_feed_watchdog;
 public:
-  ExternalWatchdogManager() { next_feed_watchdog = 0; }
+  ExternalWatchdogManager() { last_feed_watchdog = 0; }
   virtual bool begin() { return false; }
   virtual void loop() { }
   virtual unsigned long getIntervalMs() const { return 0; }
diff --git a/variants/heltec_mesh_solar/platformio.ini b/variants/heltec_mesh_solar/platformio.ini
index 1bc7e7fa..38594ecc 100644
--- a/variants/heltec_mesh_solar/platformio.ini
+++ b/variants/heltec_mesh_solar/platformio.ini
@@ -17,7 +17,7 @@ build_flags =  ${nrf52_base.build_flags}
   -D HAS_EXTERNAL_WATCHDOG
   -D EXTERNAL_WATCHDOG_DONE_PIN=9
   -D EXTERNAL_WATCHDOG_WAKE_PIN=10
-  -D EXTERNAL_WATCHDOG_TIMEOUT_MS=480000 ;(6*60*1000) ; 6 minute watchdog
+  -D EXTERNAL_WATCHDOG_FEED_INTERVAL_MS=480000 ; 8 minute feed interval, safely inside the hardware watchdog timeout
 
 build_src_filter = ${nrf52_base.build_src_filter}
   +<helpers/*.cpp>
@@ -97,4 +97,4 @@ build_src_filter = ${Heltec_mesh_solar.build_src_filter}
   +<../examples/companion_radio/*.cpp>
 lib_deps =
   ${Heltec_mesh_solar.lib_deps}
-  densaugeo/base64 @ ~1.4.0
\ No newline at end of file
+  densaugeo/base64 @ ~1.4.0
diff --git a/variants/heltec_mesh_solar/target.cpp b/variants/heltec_mesh_solar/target.cpp
index a40b8ce9..96411c55 100644
--- a/variants/heltec_mesh_solar/target.cpp
+++ b/variants/heltec_mesh_solar/target.cpp
@@ -124,7 +124,7 @@ bool SolarSensorManager::setSettingValue(const char* name, const char* value) {
 }
 
 bool SolarExternalWatchdog::begin() {
-  next_feed_watchdog = 0;
+  last_feed_watchdog = 0;
   pinMode(EXTERNAL_WATCHDOG_WAKE_PIN, INPUT);
   pinMode(EXTERNAL_WATCHDOG_DONE_PIN, OUTPUT);
   delay(1);
@@ -134,23 +134,22 @@ bool SolarExternalWatchdog::begin() {
   return true;
 }
 void SolarExternalWatchdog::loop() {
-  if (millis() > next_feed_watchdog) {
+  if (millis() - last_feed_watchdog >= EXTERNAL_WATCHDOG_FEED_INTERVAL_MS) {
     feed();
-    next_feed_watchdog = millis() + EXTERNAL_WATCHDOG_TIMEOUT_MS;
   }
 }
 
 unsigned long SolarExternalWatchdog::getIntervalMs() const {
-    unsigned long interval_ms = 0;
-    interval_ms = next_feed_watchdog - millis();
-    if(interval_ms > EXTERNAL_WATCHDOG_TIMEOUT_MS) {
-      interval_ms = EXTERNAL_WATCHDOG_TIMEOUT_MS;
+    unsigned long elapsed_ms = millis() - last_feed_watchdog;
+    if (elapsed_ms >= EXTERNAL_WATCHDOG_FEED_INTERVAL_MS) {
+      return 0;
     }
-    return interval_ms;
+    return EXTERNAL_WATCHDOG_FEED_INTERVAL_MS - elapsed_ms;
 }
 
 void SolarExternalWatchdog::feed() {
     digitalWrite(EXTERNAL_WATCHDOG_DONE_PIN, HIGH);
     delay(1);
     digitalWrite(EXTERNAL_WATCHDOG_DONE_PIN, LOW);
+    last_feed_watchdog = millis();
 }