计数器初始化设置问题

天使翎翼

  void MY_CONFIG(void)

{

//   NVIC_InitTypeDef NVIC_InitStructure;  

   GPIO_InitTypeDef GPIO_InitStructure;

   TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

   /* TIM4 clock source enable */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);

  /* Enable GPIOA, clock */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

 

GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_7; 

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; 

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz; 

GPIO_Init(GPIOB, &GPIO_InitStructure);

//TIM4输出初始化 

TIM_DeInit(TIM4);  

TIM_TimeBaseStructure.TIM_Period = 65535; //计数值 

TIM_TimeBaseStructure.TIM_Prescaler = 0; //预分频 

TIM_TimeBaseStructure.TIM_ClockDivision = 0; //时钟分割 

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //模式 

TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); //基本初始化

TIM_SetCounter(TIM4, 0); //设置 TIM4 计数器寄存器值  

 //设置 TIMx 自动重装载寄存器值 

 TIM_ARRPreloadConfig(TIM4, ENABLE);

TIM_SelectInputTrigger(TIM4, TIM_TS_TI2FP2); //若为通道1 ，则为TIM_TS_TI1FP1 

TIM_SelectSlaveMode(TIM4, TIM_SlaveMode_External1); 

TIM_Cmd(TIM4, ENABLE); //启动TIM4 

TIM_ClearFlag(TIM4, TIM_IT_CC2); //若用一通道，则此处和后面的TIM_IT_CC2都改为TIM_IT_CC1

TIM_ITConfig(TIM4, TIM_IT_CC2, ENABLE);
}

int main(void)

 {
        unsigned char n=0;

        SystemInit();

delay_init(72);     //延时初始化

NVIC_Configuration();

uart_init(9600);

  LED_Init();

KEY_Init();

while(1)

{
        delay_ms(1000);

LED0=0;

delay_ms(1000);

LED0=1;

        n=TIM_GetCounter(TIM4);

   printf("n=%d\n",n);

     }   

}  


我是想用PA.8输出脉冲，然后PB.7通道2计算这段脉冲的频率，可是读出的计数总是为0，求解答~~~

正点原子

MY_CONFIG都没调用.搞啥呢?