定时器采用外部触发方式计数

也就是外部时钟源模式2

此模式由 TIMx_SMCTRL .EXCEN 选择等于 1。计数器可以在外部触发输入 ETR 的每个上升沿或下降沿

计数。

1. 极性选择
2. 分频选择
3. 过滤选择
4. 选择外部时钟ETR模式

bsp_time_counter_ETR.h

#ifndef _BSP_TIME_COUNTER_ETR_H_
#define _BSP_TIME_COUNTER_ETR_H_

#include <stdint.h>
#include "n32l40x.h"
typedef enum
{
	
	TIME2_ETR,
	
	TIME_COUNT_ETR_NUM
}em_tim_count_etr;
//初始化函数
void bsp_timer_count_etr_all_init(void);
//获取计数值
uint32_t bsp_timer_count_etr_get_count(em_tim_count_etr id);


#endif

bsp_time_counter_ETR.c

#include "timer_counter_ETR/bsp_time_counter_ETR.h"
#include "bsp_include.h"


typedef struct
{
    GPIO_Module* gpio_grp;
    uint16_t pin;
    uint32_t gpio_rcc;
    uint8_t gpio_af;

    TIM_Module* time;
  
    uint32_t time_rcc;
    uint16_t irq_x;
    uint32_t period;//重载值
    uint32_t prescaler;//预分频器
    uint8_t it_update;
} time_counter_etr;


static time_counter_etr s_times_etr[TIME_COUNT_ETR_NUM] = {


	{GPIOA,GPIO_PIN_0, RCC_APB2_PERIPH_GPIOA,GPIO_AF5_TIM2,TIM2,RCC_APB1_PERIPH_TIM2,TIM2_IRQn,0xffff,0,1},


};

/**
 * 中断相关初始化.
 */
static void bsp_time_count_etr_nvic_config(time_counter_etr *ptime)
{
    NVIC_InitType NVIC_InitStructure;

    /* Enable the TIM1 global Interrupt */
    NVIC_InitStructure.NVIC_IRQChannel                   = ptime->irq_x;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 7;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority        = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd                = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    TIM_ClrIntPendingBit(ptime->time, TIM_INT_UPDATE);
    TIM_ConfigInt(ptime->time, TIM_INT_UPDATE, ENABLE);

}

static void bsp_time_count_etr_rcc_config(time_counter_etr *ptime)
{
    if(ptime->time==TIM1||ptime->time==TIM8)
    {
        RCC_EnableAPB2PeriphClk(ptime->time_rcc, ENABLE);
    }
    else
    {
        RCC_EnableAPB1PeriphClk(ptime->time_rcc, ENABLE);
    }

}


static  void  bsp_time_count_etr_gpio_config(time_counter_etr *ptime)
{
    GPIO_InitType GPIO_InitStructure;
  
    GPIO_InitStruct(&GPIO_InitStructure);
	
	RCC_EnableAPB2PeriphClk(ptime->gpio_rcc, ENABLE);
	
    GPIO_InitStructure.Pin        = ptime->pin;
    GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_Input;
    GPIO_InitStructure.GPIO_Current = GPIO_DC_4mA;
    GPIO_InitStructure.GPIO_Alternate = ptime->gpio_af;
    GPIO_InitPeripheral(ptime->gpio_grp, &GPIO_InitStructure);

}


/**
 * 基本定时器初始化
 */
static void bsp_time_count_etr_init(time_counter_etr *ptime)
{
    TIM_TimeBaseInitType TIM_TimeBaseStructure;

  
  
    bsp_time_count_etr_gpio_config(ptime);
    /* 1.时钟使能 */
    bsp_time_count_etr_rcc_config(ptime);



    /* Time 2.基本配置 */
    TIM_TimeBaseStructure.Period    = ptime->period;
    TIM_TimeBaseStructure.Prescaler = ptime->prescaler;//预分频器
    TIM_TimeBaseStructure.ClkDiv    = 0;
    TIM_TimeBaseStructure.CntMode   = TIM_CNT_MODE_UP;
    TIM_InitTimeBase(ptime->time, &TIM_TimeBaseStructure);



	//配置外部触发
	TIM_ConfigExtClkMode1(ptime->time,TIM_EXT_TRG_PSC_OFF,TIM_EXT_TRIG_POLARITY_NONINVERTED,0);



    //3.使能更新中断
    if(ptime->it_update)
    {
        bsp_time_count_etr_nvic_config(ptime)	;
    }
    /* 4.TIM1 使能计数 */

    TIM_Enable(ptime->time, ENABLE);
}

//一键初始化所有定时器
void bsp_timer_count_etr_all_init(void)
{
    for(int i=0; i<TIME_COUNT_ETR_NUM; i++)
    {
        bsp_time_count_etr_init(s_times_etr+i);
    }
}



uint32_t bsp_timer_count_etr_get_count(em_tim_count_etr id)
{
    uint32_t count;

    if(TIME_COUNT_ETR_NUM>id)
    {
        time_counter_etr *ptime = s_times_etr+id;
        count = TIM_GetCnt(ptime->time);
    }
    return count;
}


//定时器中断集中处理函数
static void bsp_time_count_etr_irq(time_counter_etr *ptime)
{
    if (TIM_GetIntStatus(ptime->time, TIM_INT_UPDATE) != RESET)
    {
        TIM_ClrIntPendingBit(ptime->time, TIM_INT_UPDATE);
    }

}
void TIM2_IRQHandler(void)
{

    bsp_time_count_etr_irq(s_times_etr+TIME2_ETR);

}