Added a cell blink for sandbox

Author: m19936

README.md

@@ -26,7 +26,7 @@ The AVR-IoT Cellular Mini is a development board from Microchip to develop cellu
 
 ## Examples
 
-A set of examples can be in [src/examples](./src/examples/), and in the respective user guides on the [documentation website](https://iot.microchip.com/docs/arduino/userguide/architecture). 
+A set of examples can be in [src/examples](./src/examples/), and in the respective user guides on the [documentation website](https://iot.microchip.com/docs/arduino/userguide/architecture).
 
 ![](./readme_images/examples.png)
 

src/examples/sandbox/sandbox.ino

@@ -256,14 +256,23 @@ void setup() {
     connectLTE();
 }
 
+unsigned long timeLastCellToggle = millis() + 500;
+
 void loop() {
 
     // ----------------------------------------------------------
+    if (state == NOT_CONNECTED) {
+        if ((millis() - timeLastCellToggle) > 500) {
+            LedCtrl.toggle(Led::CELL);
+            timeLastCellToggle = millis();
+        }
+    }
 
     if (event_flags & NETWORK_CONN_FLAG) {
         switch (state) {
         case NOT_CONNECTED:
             state = CONNECTED_TO_NETWORK;
+            LedCtrl.on(Led::CELL);
             Log.infof("Connected to operator: %s\r\n",
                       Lte.getOperator().c_str());
             Log.info("Connecting to MQTT broker...");