introduce external watchdog

MqttClient.cpp

@@ -21,7 +21,9 @@
 char MQTT_BROKER_DEFAULT[] = "192.168.75.1";
 const uint16_t MQTT_PORT = 1883;
 
-
+uint32_t lastWatchdogMessageReceived = 0;
+const uint32_t WATCHDOG_MESSAGE_DELAY = 10000;
+const uint32_t WATCHDOG_MESSAGE_TIMEOUT = 20000;
 
 
 String MqttConfig::exec(String params) {
@@ -172,6 +174,17 @@ String MqttConfig::exec(String params) {
 
 
 void callback(char* topic, byte* payload, unsigned int length) {
+  const char WATCHDOG_TOPIC[] = "IoT/Watchdog";
+  const char WATCHDOG_MSG[] = "WauWau!";
+
+  if (0 == strcmp(topic, WATCHDOG_TOPIC)) {
+    Serial << "Watchdog message received" << endl;
+    if (0 != strcmp((char*)payload, WATCHDOG_MSG)) {
+      Serial << "Wrong content in watchdog message" << endl;
+    } else {
+      lastWatchdogMessageReceived = millis();
+    }
+  }
 }
 
 
@@ -179,7 +192,7 @@ Metro secondTick = Metro(1000);
 
 
 MqttClient::MqttClient(RequestSender *meterBusMaster) : m_mqttConfig(this),
-                m_client(), m_meterBusMaster(meterBusMaster), m_mqttClient(m_client),
+                m_client(), m_meterBusMaster(meterBusMaster), m_mqttClient(m_client), m_alarmState(false),
                 m_disconnectState(3), m_disconnectTime(millis()), m_uptime(0), m_deviceIdx(0)
 {
 }
@@ -262,6 +275,23 @@ void MqttClient::begin(CmdServer *cmdServer) {
 }
 
 void MqttClient::exec() {
+  if (lastWatchdogMessageReceived + WATCHDOG_MESSAGE_DELAY < millis()) {
+    if (! m_alarmState) {
+      alarmOn();
+      Serial << "Entering alarm state due to missing watchdog message" << endl;
+    }
+  } else {
+    if (m_alarmState) {
+      alarmOff();
+      Serial << "Leaving alarm state due to received watchdog message" << endl;
+    }
+  }
+
+  if (lastWatchdogMessageReceived + WATCHDOG_MESSAGE_TIMEOUT < millis()) {
+    Serial << "Resetting device because of too long missing watchdog message" << endl;
+    resetDevice();
+  }
+
   //Serial << "*** a" << endl;
   if ((m_disconnectState == 0) && (! m_mqttClient.loop())) {
     m_disconnectState = 1;

MqttClient.h

@@ -53,6 +53,7 @@ private:
   EthernetClient m_client;
   RequestSender *m_meterBusMaster;
   PubSubClient m_mqttClient;
+  bool m_alarmState;
   uint8_t m_disconnectState;
   uint32_t m_disconnectTime;
   uint32_t m_uptime;

reset.cpp

@@ -19,7 +19,13 @@ void resetDevice() {
   }
 }
 
+void alarmOn() {
 
+}
+
+void alarmOff() {
+
+}
 
 void watchdogReset() {
   static uint32_t last = 0;

reset.h

@@ -11,7 +11,8 @@
 
 void resetDevice();
 void watchdogReset();
-
+void alarmOn();
+void alarmOff();
 
 
 #endif /* RESET_H_ */