请教：如何使用一个定时器实现多路频率可调PWM（占空比不要求可调）？

1楼-- · 2019-07-21 10:18

本帖最后由 Electronic 于 2018-11-8 17:37 编辑

说干就干，用原子的MINI的TIM1的4个通道配置输出4路不同频率的方波，频率可调，提供源码附件
#include "led.h"
#include "delay.h"
#include "sys.h"
#include "timer.h"

//下次增量值
uint16_t TIM1_OC1_PulseAdd = 3600;       //72M/10K/2=3600
uint16_t TIM1_OC2_PulseAdd = 3600;       //72M/10K/2=3600
uint16_t TIM1_OC3_PulseAdd = 3600;       //72M/10K/2=3600
uint16_t TIM1_OC4_PulseAdd = 3600;       //72M/10K/2=3600
//比较捕获值
uint16_t TIM1_OC1_PulseVal = 0;
uint16_t TIM1_OC2_PulseVal = 0;
uint16_t TIM1_OC3_PulseVal = 0;
uint16_t TIM1_OC4_PulseVal = 0;

void TIM1_Init(void)
{
      GPIO_InitTypeDef GPIO_InitStruct;
      TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
      TIM_OCInitTypeDef TIM_OCInitStruct;
      NVIC_InitTypeDef NVIC_InitStructure;

      //使能时钟
      RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
      RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

      //PA8 PA9 PA10 PA11复用推挽输出
      GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
      GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_InitStruct.GPIO_Pin = GPIO_Pin_8|GPIO_Pin_9|GPIO_Pin_10|GPIO_Pin_11;
      GPIO_Init(GPIOA, &GPIO_InitStruct);

      //配置定时器1
      TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
      TIM_TimeBaseStructure.TIM_Prescaler = 0;             //分频越小、精度越高、范围越小; 分频越大、精度越低、范围越大
      TIM_TimeBaseStructure.TIM_ClockDivision = 0;
      TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
      TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

      //清除比较捕获中断标志
      TIM_ClearFlag(TIM1, TIM_FLAG_CC1);
      TIM_ClearFlag(TIM1, TIM_FLAG_CC2);
      TIM_ClearFlag(TIM1, TIM_FLAG_CC3);
      TIM_ClearFlag(TIM1, TIM_FLAG_CC4);

      //配置比较捕获中断
      TIM_ITConfig(TIM1, TIM_IT_CC1, ENABLE);
      TIM_ITConfig(TIM1, TIM_IT_CC2, ENABLE);
      TIM_ITConfig(TIM1, TIM_IT_CC3, ENABLE);
      TIM_ITConfig(TIM1, TIM_IT_CC4, ENABLE);

      //比较捕获初值(必须设置，不然波形不对齐)
      TIM1_OC1_PulseVal = TIM1_OC1_PulseAdd;
      TIM1_OC2_PulseVal = TIM1_OC2_PulseAdd;
      TIM1_OC3_PulseVal = TIM1_OC3_PulseAdd;
      TIM1_OC4_PulseVal = TIM1_OC4_PulseAdd;

      //清除比较模式
      TIM1->CCMR1 &= ~((7<<4) | (7<<12));
      TIM1->CCMR2 &= ~((7<<4) | (7<<12));
      //强制为无效电平(不设置，边沿不能对其)
      TIM1->CCMR1 |= ((4<<4) | (4<<12));
      TIM1->CCMR2 |= ((4<<4) | (4<<12));

      //翻转模式
      TIM_OCStructInit(&TIM_OCInitStruct);
      TIM_OCInitStruct.TIM_OCIdleState = TIM_OCIdleState_Reset;
      TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_Toggle;             //翻转
      TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_High;       //有效电平
      TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;
      //比较捕获通道1
      TIM_OCInitStruct.TIM_Pulse = TIM1_OC1_PulseVal;
      TIM_OC1Init(TIM1, &TIM_OCInitStruct);
      //比较捕获通道2
      TIM_OCInitStruct.TIM_Pulse = TIM1_OC2_PulseVal;
      TIM_OC2Init(TIM1, &TIM_OCInitStruct);
      //比较捕获通道3
      TIM_OCInitStruct.TIM_Pulse = TIM1_OC3_PulseVal;
      TIM_OC3Init(TIM1, &TIM_OCInitStruct);
      //比较捕获通道4
      TIM_OCInitStruct.TIM_Pulse = TIM1_OC4_PulseVal;
      TIM_OC4Init(TIM1, &TIM_OCInitStruct);

      //使能中断线
      NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_IRQn;
      NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
      NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
      NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
      NVIC_Init(&NVIC_InitStructure);

      //主输出使能(高级定时器)
      TIM_CtrlPWMOutputs(TIM1, ENABLE);
      //使能定时器
      TIM_Cmd(TIM1, ENABLE);
}

int main(void)
{
      delay_init();                                                                      //延时函数初始化
      NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);       //设置中断优先级分组2
      LED_Init();                                                                               //初始化与LED连接的硬件接口
      TIM1_Init();                                                                      //PA8被配置为复用功能

      //重新配置频率
      TIM1_OC1_PulseAdd = 2400;       //72M/15K/2=2400
      TIM1_OC2_PulseAdd = 3600;       //72M/10K/2=3600
      TIM1_OC3_PulseAdd = 7200;       //72M/ 5K/2=7200
      TIM1_OC4_PulseAdd = 36000;       //72M/ 1K/2=36000
         while(1)
      {
            LED1 = !LED1;
            delay_ms(300);
      }
}

//定时器1比较捕获中断
void TIM1_CC_IRQHandler(void)
{
      if(TIM_GetITStatus(TIM1, TIM_IT_CC1) != RESET)       //比较捕获通道1
      {
            TIM_ClearITPendingBit(TIM1, TIM_IT_CC1);
            TIM1_OC1_PulseVal += TIM1_OC1_PulseAdd;             //计算下次的比较捕获值
            TIM_SetCompare1(TIM1, TIM1_OC1_PulseVal);
      }

      if(TIM_GetITStatus(TIM1, TIM_IT_CC2) != RESET)       //比较捕获通道2
      {
            TIM_ClearITPendingBit(TIM1, TIM_IT_CC2);
            TIM1_OC2_PulseVal += TIM1_OC2_PulseAdd;             //计算下次的比较捕获值
            TIM_SetCompare2(TIM1, TIM1_OC2_PulseVal);
      }

      if(TIM_GetITStatus(TIM1, TIM_IT_CC3) != RESET)       //比较捕获通道3
      {
            TIM_ClearITPendingBit(TIM1, TIM_IT_CC3);
            TIM1_OC3_PulseVal += TIM1_OC3_PulseAdd;             //计算下次的比较捕获值
            TIM_SetCompare3(TIM1, TIM1_OC3_PulseVal);
      }

      if(TIM_GetITStatus(TIM1, TIM_IT_CC4) != RESET)       //比较捕获通道4
      {
            TIM_ClearITPendingBit(TIM1, TIM_IT_CC4);
            TIM1_OC4_PulseVal += TIM1_OC4_PulseAdd;             //计算下次的比较捕获值
            TIM_SetCompare4(TIM1, TIM1_OC4_PulseVal);
      }
}

不知道怎么上传代码，只能复制到上面