Adding watchdog for SAMD architecture which is continually fed within ArduinoIoTCloud::update() to reset the board in case some function becomes stuck.

Author: aentinger

src/ArduinoIoTCloudTCP.cpp

@@ -43,6 +43,8 @@
 
 #include "cbor/CBOREncoder.h"
 
+#include "utility/watchdog/Watchdog.h"
+
 /******************************************************************************
  * EXTERN
  ******************************************************************************/
@@ -262,11 +264,36 @@ int ArduinoIoTCloudTCP::begin(String brokerAddress, uint16_t brokerPort)
   }
 #endif /* OTA_STORAGE_SNU */
 
+#ifdef ARDUINO_ARCH_SAMD
+  /* Since we do not control what code the user inserts
+   * between ArduinoIoTCloudTCP::begin() and the first
+   * call to ArduinoIoTCloudTCP::update() it is wise to
+   * set a rather large timeout at first.
+   */
+  Watchdog.enable(120 * 1000);
+#endif /* ARDUINO_ARCH_SAMD */
+
   return 1;
 }
 
 void ArduinoIoTCloudTCP::update()
 {
+#ifdef ARDUINO_ARCH_SAMD
+  /* Now that we are within the regularly called function
+   * ArduinoIoTCloudTCP::update() it's a wise idea to reduce
+   * the watchdog timeout to a smaller amount of time.
+   */
+  static bool is_watchdog_set = false;
+  if (!is_watchdog_set) {
+    Watchdog.enable(30 * 1000);
+    is_watchdog_set = true;
+  }
+  /* Feed the watchdog. If any of the functions called below
+   * get stuck than we can at least reset and recover.
+   */
+  Watchdog.reset();
+#endif /* ARDUINO_ARCH_SAMD */
+
   /* Run through the state machine. */
   State next_state = _state;
   switch (_state)

src/utility/watchdog/Watchdog.h

@@ -0,0 +1,29 @@
+/*
+   This file is part of ArduinoIoTCloud.
+
+   Copyright 2020 ARDUINO SA (http://www.arduino.cc/)
+
+   This software is released under the GNU General Public License version 3,
+   which covers the main part of arduino-cli.
+   The terms of this license can be found at:
+   https://www.gnu.org/licenses/gpl-3.0.en.html
+
+   You can be released from the requirements of the above licenses by purchasing
+   a commercial license. Buying such a license is mandatory if you want to modify or
+   otherwise use the software for commercial activities involving the Arduino
+   software without disclosing the source code of your own applications. To purchase
+   a commercial license, send an email to [email protected].
+*/
+
+#ifndef ARDUINO_AIOTC_UTILITY_WATCHDOG_H_
+#define ARDUINO_AIOTC_UTILITY_WATCHDOG_H_
+
+/******************************************************************************
+ * INCLUDE
+ ******************************************************************************/
+
+#ifdef ARDUINO_ARCH_SAMD
+#  include <Adafruit_SleepyDog.h>
+#endif /* ARDUINO_ARCH_SAMD */
+
+#endif /* ARDUINO_AIOTC_UTILITY_WATCHDOG_H_ */