The Radxa Rock has 3 LEDs on board.
|LED||GPIO ref.||GPIO number|
All are programmable using either LEDs class devices or GPIOs.
LEDs as class devices
On the latest kernel images (Ubuntu 14.04 server/desktop), the 3 LEDs are configured as LED class devices.
You can control them via /sys/class/leds/
Read the documentation for more information: https://www.kernel.org/doc/Documentation/leds/leds-class.txt
The default status of the three on board leds are:
- Red: On when there is power
- Green: Flash twice per second after the kernel booting, it's called heartbeat.
- Blue: Flash when the uSD card is reading/writing.
You can change the behaviour of each LED by using the echo command on their trigger property.
root@radxa:~ # echo none > /sys/class/leds/red/trigger root@radxa:~ # echo default-on > /sys/class/leds/red/trigger root@radxa:~ # echo timer > /sys/class/leds/red/trigger root@radxa:~ # echo heartbeat > /sys/class/leds/red/trigger
You can use cat on the trigger property to list all the available values.
root@radxa:~ # cat /sys/class/leds/red/trigger none test_ac-online test_battery-charging-or-full test_battery-charging test_battery-full test_battery-charging-blink-full-solid mmc0 mmc1 timer [heartbeat] backlight gpio default-on sleep rfkill0
Here is the list of current triggers:
The GPIO control external LEDs is moved to GPIO page.
turn off LEDs
use "none" trigger for triggered LEDs or just turn off for non-triggered LEDs.
echo none > /sys/class/leds/blue/trigger echo none > /sys/class/leds/green/trigger echo 0 > /sys/class/leds/red/brightness
you can modify kernel to change default state at boot.