5.2 LED Status Troubleshooting
| LED Sequence | Description | Diagnosis | Action | 
|---|---|---|---|
|     | All LEDs are OFF | Board is not programmed | Download the image .hexfile from GitHub
                            or the AVR-IoT website | 
|     | Only Red LED is ON | Indicates a hardware fault issue with the development board | With debug option enabled in MCC, connect to serial
                            terminal and pass the command ‘ debug 4’. This will
                            print out the log indicating the cause of the error. | 
|     | Blue LED BLINKS slowly (at 0.5s rate) with all other LEDs OFF | Board is in Soft AP mode | 
 | 
| Blue LED BLINKS quickly (at 0.25s rate) with all other LEDs OFF | Board is not connected to an access point and trying to connect. | 
 | |
|     | Green LED is BLINKING; Blue LED is also BLINKING quickly (at 0.25s rate) | Board is using WiFi DEFAULT CREDENTIALS | 
 | 
|     | Blue LED is ON, Green LED is BLINKING | Board is not connected to the AWS Cloud Servers | 
 | 
|     | Blue and Green LEDs are ON but Yellow LED is OFF | Sensor data is not being published to Cloud | 
 | 
|     | Blue and Green LEDs are ON. Yellow LED is BLINKING. | Everything is working | 
 | 
|     OR  | Blue and Green LEDs are ON. Yellow LED held high/low. | Subscribe topic toggle value received | 
 | 
| LED Sequence | Description | Diagnosis | Action | 
|---|---|---|---|
|  | PKOB nano LED is OFF | Board is not powered | 
 | 
|  | PKOB nano LED is ON but CURIOSITY driver is not found | Faulty USB connection | 
 | 
|  | PKoB nano LED is blinking | Debugger is working | No action required. Refer to the AVR-IoT Wx Hardware User Guide for more details. | 
