PWM输出问题

只看该作者 · 2013-9-25 14:35

void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

/*********  PA    6 7  ******************************/
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;    //复用
  GPIOA6_Out=1; GPIOA7_Out=1;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7;//TIM3_CH2，TIM3_CH3
  GPIO_Init(GPIOA, &GPIO_InitStructure);
}
void Timer_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
TIM_ICInitTypeDef TIM_ICInitStructure;

TIM2->CR1 &= 0xfffe;
TIM3->CR1 &= 0xfffe;

///PWM，输出的引脚是 TIM3_CH2
TIM_TimeBaseStructure.TIM_Period = 60000;
TIM_TimeBaseStructure.TIM_Prescaler = 11; //72/12=6
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3 , &TIM_TimeBaseStructure);

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;    //翻转模式
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;//使能比较匹配输出极性
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;    //设置比较匹配输出极性
TIM_OCInitStructure.TIM_Pulse = 30000;    //比较值
TIM_OC2Init(TIM3, &TIM_OCInitStructure);    //

TIM_OC2PreloadConfig(TIM3 , TIM_OCPreload_Enable);    //使能比较预装载寄存器
TIM_ARRPreloadConfig(TIM3, ENABLE);    //使能预装载寄存器

TIM3->CR1 &= 0x3fe;       //  失能 TIM 计数器
TIM3->CR2 = 0x60; //  MMS[2:0] = 110    oc2匹配上发出触发信号

/////////////// TIM2 /////
TIM_TimeBaseStructure.TIM_Period = 100;
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2 , &TIM_TimeBaseStructure);

TIM2->SMCR = 0x0000;    //禁用从模式的情况进行从模式配置
TIM2->SMCR |= 0x020; // TS[2:0]=010  TIM2触发源选择:TIM3的TRGI
TIM2->SMCR |= 0x007; // 使能从模式SMS[2:0]=111  使用内部触发 TRGI  即外部时钟1模式

TIM2->CNT = 0x00;
TIM3->CNT = 0x00;
TIM2->SR = 0x00;
TIM3->SR = 0x00;
TIM2->EGR =0x00;
TIM3->EGR =0x00;
   TIM_ITConfig(TIM2, TIM_IT_Update,ENABLE);  //使能TIM2 更新中断
TIM_ITConfig(TIM3, TIM_IT_Update,DISABLE);    //失能TIM3 更新中断
TIM_Cmd(TIM2, ENABLE);
TIM_Cmd(TIM3, ENABLE);          //DISABLE       ENABLE
}
我的疑惑是 PWM输出脚TIM3_CH2 有方波出来却无法驱动后端光耦发脉冲。
但是TIM3_CH2，用做普通I/O功能的时候却可以自己编一段仿PWM输出来驱动光耦发脉冲。

我怀疑：一：PWM输出的驱动能力没有普通IO的强。
   二：我的PWM输出配置有问题，请各位大大帮我看一下我的配置代码。