# Preface
Using pwm to realize LED lighting can be said to be a basic case of embedded systems. So how to realize PWM lighting LED lights under the embedded Linux system?
# PWM operation instructions under embedded linux
The actual usage effect is as follows. You can use shell instructions to light up the corresponding LED lights of the development board.
To light up 3 LEDs, use pwm1, pwm2 and pwm3 respectively.
#Hardware design of PWM pin
In addition to lighting, it can also control backlight. The basic principle of PWM control is to use periodic pulse signals to control the brightness of the backlight LED, that is, by adjusting the pulse width and frequency to achieve changes in the backlight brightness. Generally, the brightness of the LCD backlight is adjusted through control input to the backlight control chip. Occupied