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);}