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LED

RUBIK Pi 3 features an RGB tri-color LED driven by the Power Management IC (PMIC). By default, the green LED is set as a heartbeat indicator to reflect the system's operation status and CPU load.

LED indicator descriptions:

  • Blue LED (solid on): fastboot mode
  • Green LED (heartbeat blinking): normal operation
  • Red LED (heartbeat blinking): low-power mode (power input is less than 12V 2.25A).
  • Rapid heartbeat: high CPU load
  • No heartbeat:
    • System crash
    • Sleep mode
    • Booting up

Use the following commands under root ("sudo su") to operate the LED:

  • Turn off the heartbeat LED

    echo none > /sys/class/leds/green/trigger

  • Turn on the heartbeat LED

    echo heartbeat > /sys/class/leds/green/trigger

  • Set the brightness of the green LED (from 0 to 511. The following example sets it to 100)

    echo 100 >  /sys/class/leds/green/brightness

  • Set the brightness of the red LED (from 0 to 511. The following example sets it to 100)

    echo 100 >  /sys/class/leds/red/brightness

  • Set the brightness of the blue LED (from 0 to 511. The following example sets it to 100)

    echo 100 >  /sys/class/leds/blue/brightness