stm32f407高级定时器输出pwm标准库

下面是基于STM32F407高级定时器输出PWM的标准库代码示例：

#include "stm32f4xx.h"

int main(void)
{
    // Enable the clock for GPIOA and TIM1 peripherals
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);

    // Initialize GPIOA pin 8 as alternate function
    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_8;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    // Connect GPIOA pin 8 to TIM1 channel 1
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_TIM1);

    // Initialize TIM1
    TIM_TimeBaseInitTypeDef TIM_InitStruct;
    TIM_InitStruct.TIM_Prescaler = 0;
    TIM_InitStruct.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_InitStruct.TIM_Period = 8399; // 84MHz / 8400 = 10kHz PWM frequency
    TIM_InitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInit(TIM1, &TIM_InitStruct);

    // Initialize TIM1 channel 1 as PWM output
    TIM_OCInitTypeDef TIM_OCInitStruct;
    TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStruct.TIM_Pulse = 0; // duty cycle = 0%
    TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM1, &TIM_OCInitStruct);

    // Enable TIM1
    TIM_Cmd(TIM1, ENABLE);

    while (1)
    {
        // Vary the duty cycle from 0% to 100%
        for (int i = 0; i <= 100; i++)
        {
            TIM_SetCompare1(TIM1, i * 84);
            for (int j = 0; j < 100000; j++);
        }
    }
}

上述代码实现了在STM32F407芯片上使用TIM1通道1输出PWM信号，并通过循环改变占空比从而改变LED的亮度。需要注意的是，频率和占空比需要根据具体应用进行调整。