stm32f103 timer4 pwm 代码

以下是STM32F103的Timer4 PWM代码，可用于控制电机、LED等设备的亮度和速度等：

#include "stm32f10x.h"

int main(void) {
  
  // 初始化GPIO
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  // 初始化Timer4
  TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
  TIM_TimeBaseStructure.TIM_Period = 3999;
  TIM_TimeBaseStructure.TIM_Prescaler = 7199;
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);

  // 初始化PWM输出
  TIM_OCInitTypeDef TIM_OCInitStructure;
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = 2000;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
  TIM_OC3Init(TIM4, &TIM_OCInitStructure);

  // 启动Timer4
  TIM_Cmd(TIM4, ENABLE);

  while (1) {
    // 修改PWM占空比
    TIM_SetCompare3(TIM4, 1000);
    delay_ms(1000);
    TIM_SetCompare3(TIM4, 3000);
    delay_ms(1000);
  }
}