MAGIC value for powerReason should be stored in RTC backup on Horus (#7096)

- Allows the radio main application to start correctly when coming from an app in RAM
- Refactoring of the `UNEXPECTED_SHUTDOWN()` process
- Saves the RTC battery as BACKUP RAM is not needed on normal shutdown
- On PWR OFF on an ALERT, the radio won't show the next alert before shutting down
- Bootloader flashable through the SD Manager

radio/src/opentx.cpp

@@ -109,7 +109,7 @@ void per10ms()
 
   if (watchdogTimeout) {
     watchdogTimeout -= 1;
-    wdt_reset();  // Retrigger hardware watchdog
+    WDG_RESET();  // Retrigger hardware watchdog
   }
 
 #if defined(GUI)
@@ -932,7 +932,7 @@ void checkAll()
     tmr10ms_t tgtime = get_tmr10ms() + 500;
     while (tgtime != get_tmr10ms()) {
       RTOS_WAIT_MS(1);
-      wdt_reset();
+      WDG_RESET();
     }
   }
 
@@ -999,6 +999,8 @@ void checkThrottleStick()
 #if defined(PWR_BUTTON_PRESS)
     uint32_t power = pwrCheck();
     if (power == e_power_off) {
+      drawSleepBitmap();
+      boardOff();
       break;
     }
     else if (power == e_power_press) {
@@ -1016,7 +1018,7 @@ void checkThrottleStick()
 
     doLoopCommonActions();
 
-    wdt_reset();
+    WDG_RESET();
 
     RTOS_WAIT_MS(10);
   }
@@ -1047,7 +1049,7 @@ void alert(const char * title, const char * msg , uint8_t sound)
   bool refresh = false;
 #endif
 
-  while (1) {
+  while (true) {
     RTOS_WAIT_MS(10);
 
     if (keyDown())  // wait for key release
@@ -1055,7 +1057,7 @@ void alert(const char * title, const char * msg , uint8_t sound)
 
     doLoopCommonActions();
 
-    wdt_reset();
+    WDG_RESET();
 
     const uint32_t pwr_check = pwrCheck();
     if (pwr_check == e_power_off) {
@@ -1858,6 +1860,10 @@ void opentxInit()
     globalData.unexpectedShutdown = 1;
   }
 
+#if defined(RTC_BACKUP_RAM)
+  SET_POWER_REASON(0);
+#endif
+
 #if defined(SDCARD)
   // SDCARD related stuff, only done if not unexpectedShutdown
   if (!globalData.unexpectedShutdown) {
@@ -1909,7 +1915,7 @@ void opentxInit()
 
   // handling of storage for radios that have no EEPROM
 #if !defined(EEPROM)
-#if defined(RAMBACKUP) && !defined(SIMU)
+#if defined(RTC_BACKUP_RAM) && !defined(SIMU)
   if (globalData.unexpectedShutdown) {
     // SDCARD not available, try to restore last model from RAM
     TRACE("rambackupRestore");
@@ -1966,20 +1972,22 @@ void opentxInit()
     opentxStart();
   }
 
-  // TODO Horus does not need this
+#if !defined(RTC_BACKUP_RAM)
   if (!g_eeGeneral.unexpectedShutdown) {
     g_eeGeneral.unexpectedShutdown = 1;
     storageDirty(EE_GENERAL);
   }
+#endif
 
 #if defined(GUI)
   lcdSetContrast();
 #endif
+
   backlightOn();
 
   startPulses();
 
-  wdt_enable(WDTO_500MS);
+  WDG_ENABLE(WDG_DURATION);
 }
 
 #if defined(SIMU)
@@ -2001,7 +2009,7 @@ int main()
 
   // G: The WDT remains active after a WDT reset -- at maximum clock speed. So it's
   // important to disable it before commencing with system initialisation (or
-  // we could put a bunch more wdt_reset()s in. But I don't like that approach
+  // we could put a bunch more WDG_RESET()s in. But I don't like that approach
   // during boot up.)
 #if defined(PCBTARANIS)
   g_eeGeneral.contrast = LCD_CONTRAST_DEFAULT;
@@ -2018,7 +2026,9 @@ int main()
 #endif
 
 #if defined(SPLASH) && !defined(STARTUP_ANIMATION)
-  drawSplash();
+  if (!UNEXPECTED_SHUTDOWN()) {
+    drawSplash();
+  }
 #endif
 
 #if defined(PCBHORUS)