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Table of Contents
LED
Introduction
Onboard LED indicators usage under Linux . You will learn how to control the LEDs.
LED Information
| I2C | PIN & GPIO(#number) | DT Overlays Node | Bus Number | Device Node | |
|---|---|---|---|---|---|
| VIM1/2 | I2C A | SCL(22) - GPIODV_25 (#474) SDA (23) - GPIODV_24 (#473) | i2c0 | 0 | /dev/i2c-0 |
| I2C B | SCL(25) - GPIODV_27 (#476) SDA(26) - GPIODV_26 (#475) | - | 1 | /dev/i2c-1 | |
| VIM3/3L | I2CM 3 | SCL(22) - GPIOA_15 (#475) SDA(23) - GPIOA_14 (#474) | i2c3 | 3 | /dev/i2c-3 |
| I2C AO | SCL(25) - GPIOAO_2 (#498) SDA(26) - GPIOAO_3 (#499) | - | 4 | /dev/i2c-4 | |
| VIM4 | I2CM F | SCL(22) - GPIOY_17 (#501) SDA (23) - GPIOY_18 (#502) | i2cm_f | 5 | /dev/i2c-5 |
| I2CM A | SCL(25) - GPIOT_20 (#466) SDA(26) - GPIOT_21 (#467) | i2cm_a | 0 | /dev/i2c-0 |
VIM1/2
VIM1/VIM2 has only one node.
$ ls /sys/class/leds
sys_led
VIM3/3L
VIM3/VIM3L has two nodes.
$ ls /sys/class/leds
red_led sys_led
VIM4
VIM4 has only one node which is a PWM LED.
$ ls /sys/class/leds
pwmled
Edge1
Edge1 has two nodes.
$ ls /sys/class/leds
read_led sys_led
Edge2
Setup LED
VIM1/2/3/3L
We will take sys_led (white) as an example.
Turn off
Set the LED node parameter to none to turn off the LED:
$ echo none | sudo tee /sys/class/leds/sys_led/trigger
Turn on
Set the LED node parameter to default-on to keep the LED permanently on:
$ echo default-on | sudo tee /sys/class/leds/sys_led/trigger
Set LED heartbeat
Set the LED node parameter to heartbeat, to make the LED flash with a heartbeat blink:
$ echo heartbeat > /sys/class/leds/sys_led/trigger
You can also try other parameters.
VIM4
We will take pwmled (white) as an example.
Turn off
Set the LED node parameter to none to turn off the LED:
$ echo none | sudo tee /sys/class/leds/pwmled/trigger
Turn on
Set the LED node parameter to default-on, to make the LED permanently on:
$ echo default-on | sudo tee /sys/class/leds/pwmled/trigger
Set LED heartbeat
Set the LED node parameter to heartbeat, to make the LED flash with a heartbeat blink:
$ echo heartbeat > /sys/class/leds/pwmled/trigger
You can also experiment with other parameters.
Edge1
We will use sys_led as an example:
Turn off
Set the LED node parameter to none to turn off the LED:
$ echo none | sudo tee /sys/class/leds/sys_led/trigger
Turn on
Set the LED node parameter to default-on to keep the LED permanently on:
$ echo default-on | sudo tee /sys/class/leds/sys_led/trigger
Set LED heartbeat
Set the LED node parameter to heartbeat, to make the LED flash with a heartbeat blink:
$ echo heartbeat > /sys/class/leds/sys_led/trigger
You can also experiment with other parameters.