在keil5中用stm32f103c8t6 实现pwm呼吸灯的工程代码

好的，以下是基于Keil5和STM32F103C8T6的PWM呼吸灯工程代码：

#include "stm32f10x.h"

void PWM_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    
    // 开启TIM2时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    
    // 开启GPIOA时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    
    // 配置GPIOA.1为复用推挽输出
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    
    // 配置TIM2
    TIM_TimeBaseStructure.TIM_Period = 999; // 定时器周期为1000
    TIM_TimeBaseStructure.TIM_Prescaler = 719; // 分频系数为720
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
    
    // 配置TIM2通道1为PWM模式
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0; // 初始占空比为0
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM2, &TIM_OCInitStructure);
    
    // 使能TIM2
    TIM_Cmd(TIM2, ENABLE);
}

int main(void)
{
    PWM_Configuration();
    
    uint16_t duty_cycle = 0;
    uint8_t direction = 1;
  
    while (1)
    {
        TIM_SetCompare1(TIM2, duty_cycle);
        if (duty_cycle == 999) {
            direction = 0;
        }
        else if (duty_cycle == 0) {
            direction = 1;
        }
        if (direction == 1) {
            duty_cycle += 10;
        }
        else {
            duty_cycle -= 10;
        }
        for (int i = 0; i < 100000; i++); // 延时
    }
}

这段代码使用了TIM2的通道1来输出PWM信号，使用了GPIOA.1作为输出引脚。在主循环中，通过改变占空比的大小来实现呼吸灯的效果。