STM32 timer as external pulse signal counter-EEWORLD

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Today, I tried to use the external clock function of the STM32 counter to count the external pulse signal. The effect is quite good. The specific settings are as follows:

/* TIM3_CH2 is the pulse input port
1. Configure GPIO_GPIOA_PIN7 input
2. Configure TIM3 counter to count the rising edge at TI2:
    1). TIMx_CCMR1: CC2S =01; Configure channel 2 to detect the rising edge of TI2 input
    2). TIMx_CCMR1:IC2F =000; Select input filter bandwidth
    3). TIMx_CCER: CC2P =0; Configure rising edge polarity √
    4). TIMx_SMCR: SMS =111; Select timer external clock mode 1
    5). TIMx_SMCR: TS =110; Select TI2 as the trigger input source √
    6). TIMx_CR1: CEN =1; Start the counter
*/

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; /*
                                                                            The division ratio between the timer clock (CK_INT) frequency and the sampling frequency used by the digital filter (ETR,TIx) is 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

Determined by TIM_TIxExternalCLK1Source_TI2
TIM_ICSelection = TIM_ICSelection_DirectTI: CCMR1_CC2S = 01;

TIM_ICPolarity_Rising = CCER_CC2P
TIM_TIxExternalCLK1Source_TI2 = TIM_SMCR_TS

This function defines TIM_SlaveMode_External1; external clock mode 1
*/

TIM_TIxExternalClockConfig(TIM3,TIM_TIxExternalCLK1Source_TI2,TIM_ICPolarity_Rising,0);
// TIM_SetCounter(TIM3, 0); // Clear counter CNT
// TIM_Cmd(TIM3,ENABLE);

}

// Here is how to use it:

    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;
            }
    };

The above procedures have been tested on the hardware.

Keywords：STM32 Reference address：STM32 timer as external pulse signal counter

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