Wi-Fi LED states

LinkIt Smart 7688 development board doesn't have a display that shows information such as system states through a GUI. Instead, it utilizes the on-board Wi-Fi LED to provide information about the system states. Understanding the LED patterns and corresponding system states can help you to identify and diagnose problems.The on-board Wi-Fi LED status indicator is located near the PWR micro-USB port and labeled as WiFi. This document introduces the LED behavior and its meaning under different circumstances. The image below gives a summary of the LED states.

After powering up or resetting the device, the Wi-Fi LED will blink once to indicate the bootloader is in initialization process. Following the bootloader initialization, which takes about 4 seconds, the Linux kernel is loaded and starts the bootup process. When the Linux is booting up, the Wi-Fi LED will light on steadily. It takes about 30 seconds for the Linux kernel to initialize subsystems. Once the Linux completes the boot-up process and the Wi-Fi subsystem is ready, the LED switches off.

From this point on, the LED will have different behaviors according to different Wi-Fi configuration. The LinkIt Smart 7688 development board can operate under 2 different modes, the Access Point (AP) mode and the Station mode. The AP mode forms a Wi-Fi network that allows your computer to join, and the Station mode enables the board to join other Wi-Fi networks formed by other Wi-Fi access points.

In AP mode

There are 2 Wi-Fi LED states in AP mode:

  1. The LED is off. It means no client device is connected to the LinkIt Smart 7688 development board.
  2. The LED blinks 3 times per second and pauses for 0.5 seconds, and repeats the pattern. This indicates there is at least 1 client device connected to the LinkIt Smart 7688 development board.

In Station mode

There are 3 Wi-Fi LED states in Station mode:

  1. The LED is off. The LinkIt Smart 7688 development board failed to connect to a wireless router and is timed-out.
  2. The LED blinks twice per second continuously. It indicates the LinkIt Smart 7688 development board is connecting to a wireless router.
  3. The LED blinks according to data transmission. The LinkIt Smart 7688 development board has connected to a wireless router and the Wi-Fi LED will blink as data is transmitting.

Common errors

The Wi-Fi LED state is an important indicator for troubleshooting network configuration issues - here's a list of common errors and how to fix them.

LED stateProblemFixes
After switching to Station mode, the Wi-Fi LED keeps blinking twice per second, then switches off.It has failed to join the Wi-Fi network you've assigned.Press the WiFi button for at least 5 seconds and release to restore the Wi-Fi mode to AP. Re-connect and re-configure the Wi-Fi settings accordingly.
After resetting the device, the Wi-Fi LED doesn’t blink at all.The bootloader is corrupted or the on-board flash is damaged.The device is bricked. You need to re-program the flash using an external hardware flash programmer.
The Wi-Fi LED lights up (doesn’t switch off).Linux has failed to initialize properly.This is usually caused by a damaged system image or corrupted Wi-Fi driver. You can resolve this by updating the firmware using a USB drive. Please refer to LinkIt Smart 7688 Developer’s Guide section 4.6.1, “Upgrading Firmware”, for more information.
The Wi-Fi LED blinks once after reset, but does not light up.It failed to load the Linux kernel.This is usually caused by a damaged system image. You can resolve this by updating the firmware using a USB drive. Please refer to LinkIt Smart 7688 Developer’s Guide section 4.6.1, “Upgrading Firmware”, for more information.