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1.硬件

• STM32单片机最小系统
• 按键模块

2.软件

• 定时器HAL驱动层文件添加
• ic驱动文件添加
• GPIO常用函数
• 定时器输入捕获实验配置步骤
• main.c程序

#include "sys.h"
#include "delay.h"
#include "led.h"
#include "uart1.h"
#include "ic.h"int main(void)
{HAL_Init();                         /* 初始化HAL库 */stm32_clock_init(RCC_PLL_MUL9);     /* 设置时钟, 72Mhz */led_init();                         /* 初始化LED灯 */uart1_init(115200);printf("hello world!\r\n");ic_init(65536 - 1, 72 - 1);while(1){ pressed_time_get();delay_ms(10);
//        led1_on();
//        led2_off();
//        delay_ms(500);
//        led1_off();
//        led2_on();
//        delay_ms(500);}
}

• **ic_init(65536 - 1, 72 - 1);//计时1us**语句定时参考

• ic.c程序

#include "ic.h"
#include "stdio.h"
#include "string.h"struct
{uint8_t succeed_flag;uint8_t rising_flag;uint8_t falling_flag;uint16_t timout_cnt;
} capture_status = {0};uint16_t last_cnt = 0;TIM_HandleTypeDef ic_handle = {0};
void ic_init(uint16_t arr, uint16_t psc)
{TIM_IC_InitTypeDef ic_config = {0};ic_handle.Instance = TIM2;ic_handle.Init.Prescaler = psc;ic_handle.Init.Period = arr;ic_handle.Init.CounterMode = TIM_COUNTERMODE_UP;HAL_TIM_IC_Init(&ic_handle);ic_config.ICPolarity = TIM_ICPOLARITY_FALLING;ic_config.ICSelection = TIM_ICSELECTION_DIRECTTI;ic_config.ICPrescaler = TIM_ICPSC_DIV1;ic_config.ICFilter = 0;HAL_TIM_IC_ConfigChannel(&ic_handle, &ic_config, TIM_CHANNEL_2);__HAL_TIM_ENABLE_IT(&ic_handle, TIM_IT_UPDATE);HAL_TIM_IC_Start_IT(&ic_handle, TIM_CHANNEL_2);
}void HAL_TIM_IC_MspInit(TIM_HandleTypeDef *htim)
{if(htim->Instance == TIM2){GPIO_InitTypeDef gpio_initstruct;//打开时钟__HAL_RCC_GPIOA_CLK_ENABLE();                           // 使能GPIOB时钟__HAL_RCC_TIM2_CLK_ENABLE();//调用GPIO初始化函数gpio_initstruct.Pin = GPIO_PIN_0;                    // 两个LED对应的引脚gpio_initstruct.Mode = GPIO_MODE_AF_PP;             // 推挽输出gpio_initstruct.Pull = GPIO_PULLUP;                     // 上拉gpio_initstruct.Speed = GPIO_SPEED_FREQ_HIGH;           // 高速HAL_GPIO_Init(GPIOB, &gpio_initstruct);HAL_NVIC_SetPriority(TIM2_IRQn, 2, 2);HAL_NVIC_EnableIRQ(TIM2_IRQn);}
}void TIM2_IRQHandler(void)
{HAL_TIM_IRQHandler(&ic_handle);
}void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{//printf("捕获到下降沿\r\n");if(htim->Instance == TIM2){if(capture_status.succeed_flag == 0){if(capture_status.falling_flag == 1){printf("捕获到上升沿\r\n");capture_status.succeed_flag = 1;last_cnt = HAL_TIM_ReadCapturedValue(&ic_handle, TIM_CHANNEL_2);TIM_RESET_CAPTUREPOLARITY(&ic_handle, TIM_CHANNEL_2);TIM_SET_CAPTUREPOLARITY(&ic_handle, TIM_CHANNEL_2, TIM_ICPOLARITY_FALLING);//memset(&capture_status, 0, sizeof(capture_status));}else{printf("捕获到下降沿\r\n");memset(&capture_status, 0, sizeof(capture_status));capture_status.falling_flag = 1;__HAL_TIM_DISABLE(&ic_handle);__HAL_TIM_SET_COUNTER(&ic_handle, 0);//定时器清零TIM_RESET_CAPTUREPOLARITY(&ic_handle, TIM_CHANNEL_2);TIM_SET_CAPTUREPOLARITY(&ic_handle, TIM_CHANNEL_2, TIM_ICPOLARITY_RISING);__HAL_TIM_ENABLE(&ic_handle);}}}
}void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{if(htim->Instance == TIM2){if(capture_status.succeed_flag == 0){if(capture_status.falling_flag == 1)capture_status.timout_cnt++;}}
}void pressed_time_get(void)
{if(capture_status.succeed_flag == 1){printf("按下时间：%d us\r\n", capture_status.timout_cnt * 65536 + last_cnt);memset(&capture_status, 0, sizeof(capture_status));}
}

• ic.h程序

#ifndef __IC_H__
#define __IC_H__#include "sys.h"
void ic_init(uint16_t arr, uint16_t psc);
void pressed_time_get(void);#endif

3.实物效果

• 硬件模块接线
  KEY一端—>PA0
  KEY另一端—>GND
  ST-Link下载方式
  打开串口软件，当按键按下时，串口打印输出“捕获到下降沿”；当按键松开时，串口打印输出“捕获到上升沿”；并打印“按下时间：”

测量按键按下时间keil源文件