STM32定时器做外部脉冲信号计数器用

具体设置如下：

/* TIM3_CH2 为脉冲输入口

1. 配置GPIO_GPIOA_PIN7 输入

2. 配置TIM3 计数器在TI2 端的上升沿计数:

1). TIMx_CCMR1: CC2S =01; 配置通道2检测TI2输入的上升沿

2). TIMx_CCMR1:IC2F =000; 选择输入滤波器带宽

3). TIMx_CCER: CC2P =0; 配置上升沿极性 √

4). TIMx_SMCR: SMS =111; 选择定时器外部时钟模式1

5). TIMx_SMCR: TS =110; 选择TI2作为触发输入源 √

6). TIMx_CR1: CEN =1; 启动计数器

*/

void TIM3_External_Clock_CountingMode(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

// TIM_ICInitTypeDef TIM_ICInitStructure;

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_50MHz;

GPIO_Init(GPIOA, &GPIO_InitStructure);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

TIM_DeInit(TIM3);

TIM_TimeBaseStructure.TIM_Period = 0xFFFF;

TIM_TimeBaseStructure.TIM_Prescaler = 0x00;

TIM_TimeBaseStructure.TIM_ClockDivision = 0x0; /*定时器时钟(CK_INT)频率与数字滤波器(ETR,TIx)

使用的采样频率之间的分频比为1*/

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure); // Time base configuration

/*

tmpccmr1 |= (uint16_t)(TIM_ICFilter << 12); // CCMR1_IC2F

tmpccmr1 |= (uint16_t)(TIM_ICSelection << 8); // CCMR1_CC2S

由TIM_TIxExternalCLK1Source_TI2决定了

TIM_ICSelection=TIM_ICSelection_DirectTI: CCMR1_CC2S = 01;

TIM_ICPolarity_Rising = CCER_CC2P

TIM_TIxExternalCLK1Source_TI2 = TIM_SMCR_TS

该函数定义了TIM_SlaveMode_External1;外部时钟模式1

*/

TIM_TIxExternalClockConfig(TIM3,TIM_TIxExternalCLK1Source_TI2,TIM_ICPolarity_Rising,0);

// TIM_SetCounter(TIM3, 0); // 清零计数器CNT

// TIM_Cmd(TIM3,ENABLE);

}

// 下面是使用方法：

TIM3_External_Clock_CountingMode();

TIM_SetCounter(TIM3, 0); // 清零计数器CNT

TIM_Cmd(TIM3,ENABLE);

SecCnt = 0;

TFgs.Secok = 0;

i=0;

while(1)

{

Delay_Nms(1000);

CountPulse = TIM_GetCounter(TIM3);

DisplayDat(10,10+24*i,CountPulse,5);

TFgs.Secok = 0;

if(++CountTims>=120)

{

TIM_Cmd(TIM3,DISABLE);

CountPulse = TIM_GetCounter(TIM3);

DisplayDat(10,10+24*i,CountPulse,5);

if(++i>11)i=0;

TIM_SetCounter(TIM3, 0); // 清零计数器CNT

TIM_Cmd(TIM3,ENABLE);

SecCnt = 0;

TFgs.Secok = 0;

CountTims =0;

}

};

上述程序经过硬件测试。