为什么我用tim3使能PWM没有波

只看该作者 · 2015-7-26 16:44

我不用TIM1，程序如下：
#include "time.h"

TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
uint16_t TimerPeriod = 0;
uint16_t Channel1Pulse = 0, Channel2Pulse = 0, Channel3Pulse = 0, Channel4Pulse = 0;

void TIM_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  /* 使能GPIO时钟 */
  RCC_AHBPeriphClockCmd( RCC_AHBPeriph_GPIOA, ENABLE);

  /* 配置GPIO管脚复用*/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 ;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;
  GPIO_Init(GPIOA, &GPIO_InitStructure);


  GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_1);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_1);


}

void TIM_PWM_Config(void)
{

/*计算预定表的值，也就是多少个时钟计数为一个周期*/
  TimerPeriod = (SystemCoreClock / 17570 ) - 1;
  /*计算CCR1 跳转值在占空比为50%时*/
Channel1Pulse = (uint16_t) (((uint32_t) 5 * (TimerPeriod - 1)) / 10);
/*计算CCR2 跳转值在占空比为37.5%时*/
  Channel2Pulse = (uint16_t) (((uint32_t) 375 * (TimerPeriod - 1)) / 1000);

  /* TIM1 时钟使能 */
  RCC_APB2PeriphClockCmd(RCC_APB1Periph_TIM3 , ENABLE);

  /* Time 定时基础设置*/
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  /* Time 定时设置为上升沿计算模式*/
  TIM_TimeBaseStructure.TIM_Period = TimerPeriod;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  /* 频道1，2，3，4的PWM 模式设置 */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
  TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
  TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
  TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;

  TIM_OCInitStructure.TIM_Pulse = Channel1Pulse;//使能频道1配置
  TIM_OC1Init(TIM3, &TIM_OCInitStructure);

  TIM_OCInitStructure.TIM_Pulse = Channel2Pulse;//使能频道2配置
  TIM_OC2Init(TIM3, &TIM_OCInitStructure);

//  TIM_OCInitStructure.TIM_Pulse = Channel3Pulse;//使能频道3配置
//  TIM_OC3Init(TIM1, &TIM_OCInitStructure);

//  TIM_OCInitStructure.TIM_Pulse = Channel4Pulse;//使能频道4配置
//  TIM_OC4Init(TIM1, &TIM_OCInitStructure);

  /* TIM1 计算器使能*/
  TIM_Cmd(TIM3, ENABLE);

  /* TIM1 主输出使能 */
  TIM_CtrlPWMOutputs(TIM3, ENABLE);
}