LED dimming circuit based on STM32

Main control : STM32F103C8T6

Function : 12-level LED brightness control

           Breathing light effect (adjustable speed)

Instructions :

         1. Dimming mode

                It enters the dimming mode when it is turned on, including 12 levels of brightness. Press KEY1 to increase the brightness, and KEY2 to increase the brightness. When the extreme value is reached, the LED flashes to indicate.

         2. Breathing light mode

                After powering on, long press KEY1 to enter the breathing light mode, press KEY1 to accelerate breathing, and vice versa for KEY2. When the extreme value is reached, the LED flashes to indicate.

                In the breathing light mode, press and hold KEY1 again to exit the breathing light mode.

Hardware support : STM32F103C8 external crystal oscillator 8MHz RCC function setting main frequency 72MHz　  

       Pin occupation :

PA3~PA4         keys KEY1~KEY2

PB8 LED-PWM (TIM4-CH3)

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