system-leds.md

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System LEDs Guide for HiKey	/documentation/consumer/hikey/hikey620/guides/system-leds.md.html	/documentation/ConsumerEdition/HiKey/Guides/SystemLEDs.md.html /documentation/consumer/hikey/guides/system-leds.md.html

System LEDs

Each board led has a directory in /sys/class/leds. By default the LEDs use the following triggers:

LED	Trigger
wifi_active	phy0tx (WiFi Tx)
bt_active	hci0tx (Bluetooth Tx)
user_led1	heartbeat
user_led2	mmc0 (disk access, eMMC)
user_led3	mmc1 (disk access, microSD card)
user_led4	CPU core 0 active(not used)

To change a user LED you can do the following as a root user:

# echo heartbeat > /sys/class/leds/<led_dir>/trigger      make a LED flash
# cat /sys/class/leds/<led_dir>/trigger                   show triggers
# echo none > /sys/class/leds/<led_dir>/trigger           remove triggers    
# echo 1 > /sys/class/leds/<led_dir>/brightness           turn LED on
# echo 0 > /sys/class/leds/<led_dir>/brightness           turn LED off