stm32f103c8采集ad控制pwm占空比

以下是一个示例代码，用于在STM32F103C8上采集ADC值并控制PWM占空比：

#include "stm32f10x.h"

uint16_t ADC_Value;

void ADC_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  ADC_InitTypeDef ADC_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_ADC1, ENABLE);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
  ADC_InitStructure.ADC_ScanConvMode = DISABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfChannel = 1;
  ADC_Init(ADC1, &ADC_InitStructure);

  ADC_Cmd(ADC1, ENABLE);
}

void PWM_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
  TIM_OCInitTypeDef TIM_OCInitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  TIM_TimeBaseStructure.TIM_Period = 1000;
  TIM_TimeBaseStructure.TIM_Prescaler = 72;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = 0;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
  TIM_OC1Init(TIM3, &TIM_OCInitStructure);

  TIM_Cmd(TIM3, ENABLE);
}

int main(void)
{
  ADC_Configuration();
  PWM_Configuration();

  while (1)
  {
    ADC_SoftwareStartConvCmd(ADC1, ENABLE);
    while (ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);
    ADC_Value = ADC_GetConversionValue(ADC1);

    TIM_SetCompare1(TIM3, ADC_Value * 1000 / 4096);
  }
}

该代码将ADC1的通道1配置为模拟输入，并使用软件触发ADC转换。ADC值在每次转换后存储在`ADC_Value`变量中。

PWM使用TIM3的通道1输出到GPIOB的引脚0上，其占空比由`TIM_SetCompare1()`函数设置。在此例中，PWM周期为1ms，预分频为72，因此计数器将计数到72,000，然后重新开始。`TIM_SetCompare1()`函数将ADC值转换为0-1000之间的占空比。注意，这将使用PWM的最大值作为100％的占空比，因此在此例中，100％的占空比为1,000，而不是1,024或其他值。