Use LED to display join state

main.cpp

@@ -44,7 +44,7 @@ AnalogIn bat(MBED_CONF_APP_BATTERY_ADC);
 DHT dht(MBED_CONF_APP_DHT_DATA, MBED_CONF_APP_DHT_TYPE);
 #endif
 
-DigitalOut led(LED1);
+DigitalOut led(LED1, 1);
 
 int main(void) {
 
@@ -78,6 +78,8 @@ int main(void) {
 
     printf("\r\n Adaptive data  rate (ADR) - Enabled \r\n");
 
+    led = 0;
+
     retcode = lorawan.connect();
 
     if (retcode == LORAWAN_STATUS_OK ||
@@ -166,6 +168,7 @@ static void lora_event_handler(lorawan_event_t event)
 {
     switch (event) {
         case CONNECTED:
+            led = 1;
             printf("\r\n Connection - Successful \r\n");
             if (MBED_CONF_LORA_DUTY_CYCLE_ON) {
                 send_message();