代码收藏家 【STM32】状态机实现定时器按键消抖，处理多种点击事件
目录
一、简单介绍
二、模块与接线
三、cubemx配置
四、驱动编写
状态图
按键类型定义
参数初始化/复位
按键扫描
串口重定向
主函数
五、效果展示
六、驱动附录
key.c
key.h
一、简单介绍
众所周知，普通的机械按键会产生抖动，可以采取硬件上加电容来滤波，也可以考虑用软件来消抖。这里笔者分享一种基于状态机的按键消抖策略，可以实现单击，双击，三击，长按事件的读取。按键时间也可以自己设置。
这种方法需要消耗掉定时器资源，还有额外的RAM支出。
二、模块与接线
笔者使用STM32单片机来实现这一过程，具体型号为STM32F103CBT6，和常见的最小核心板引脚是一样的，只是容量大一些。
外部按键选择的是51单片机的独立按键，原理图如下
按下按键后，相应的引脚电平就为低。将P30,P31,P32,P33分别连接至单片机的PA1,PA2,PA3,PA4
三、cubemx配置
GPIO口开启对应的按键为输入模式，配置上拉
串口
时钟为72MHz
定时器设置为10ms触发一次
四、驱动编写
状态图
将一个按键从按下前到按下再到松手分成四个状态：无操作、按下、按压、弹起
对应的状态图如下，分别是四个圆形
按键类型定义
如图矩形框内描述，最终键值的确定需要标志位和计数值，因此一个按键结构体应该这样定义
typedef struct
{
GPIO_TypeDef * GPIO_Port; //按键端口
uint16_t GPIO_Pin; //按键PIN
KeyActionType key; //按键类型
uint16_t hold_cnt; //按压计数器
uint16_t high_cnt; //高电平计数器
uint8_t press_flag; //按压标志
uint8_t release_flag; //松手标志
ButtonActionType buttonAction; //按键键值
}buttonType;该工程需要配置的只有一个主函数文件，外加笔者编写的key.c和key.h还有串口重定向的部分
参数初始化/复位
void Key_ParaInit(buttonType* button)
{
button->high_cnt = 0;
button->hold_cnt = 0;
button->press_flag = 0;
button->release_flag = 0;
}按键扫描
代码如下，基本实现了状态图
void Key_Scan(buttonType* button)
{
switch(button->key)
{
case KEY_NULL:
{
/* if falling edge captured */
if(HAL_GPIO_ReadPin(button->GPIO_Port,button->GPIO_Pin) == 0)
{
button->key = KEY_DOWN;
}
else if(HAL_GPIO_ReadPin(button->GPIO_Port,button->GPIO_Pin) == 1)
{
button->key = KEY_NULL;
}
/* if button is released ,high_time_count++ */
if(button->release_flag == 1)
{
button->high_cnt++;
}
/**********************judge***********************/
/* if high_time_count is longer than LONG_PRESS_TIME, consider BUTTON_LONG_PRESS */
if(button->hold_cnt > LONG_PRESS_TIME)
{
button->buttonAction = BUTTON_LONG_PRESS;
Key_ParaInit(button);
}
/* if high_time_count is shorter than LONG_PRESS_TIME,but longer than CLICK_MAX_TIME consider INVALID */
else if(button->hold_cnt < LONG_PRESS_TIME && button->hold_cnt > CLICK_MAX_TIME)
{
Key_ParaInit(button);
}
/*
only the latest press time is in range of [CLICK_MIN_TIME,CLICK_MAX_TIME] can be regarded valid
if high level time > JUDGE_TIME also means that over the JUDGE_TIME and still dont have button pushed
we can check the flag value to get button state now
*/
else if((button->high_cnt > JUDGE_TIME)&&(button->hold_cnt > CLICK_MIN_TIME && button->hold_cnt < CLICK_MAX_TIME))
{
if(button->press_flag ==1)
{
button->buttonAction = BUTTON_SINGLE;
}
else if(button->press_flag == 2)
{
button->buttonAction = BUTTON_DOUBLE;
}
else if(button->press_flag == 3)
{
button->buttonAction = BUTTON_TRIPLE;
}
Key_ParaInit(button);
}
break;
}
case KEY_DOWN:
{
button->key = KEY_PRESS;
/* as long as falling edge occurring,press_flag++ */
button->press_flag++;
button->release_flag = 0; /* means that the button has been pressed */
button->hold_cnt = 0; /* reset hold time count */
break;
}
case KEY_PRESS:
{
/* when button was kept pressed, hold count++ */
if(HAL_GPIO_ReadPin(button->GPIO_Port,button->GPIO_Pin) == 0)
{
button->key = KEY_PRESS;
button->hold_cnt++;
}
/* when button was released, change state */
else if(HAL_GPIO_ReadPin(button->GPIO_Port,button->GPIO_Pin) == 1)
{
button->key = KEY_UP;
}
break;
}
case KEY_UP:
{
button->key = KEY_NULL;
button->release_flag = 1; /* means that the button is released */
button->high_cnt = 0; /* reset hold time count */
/* if press time is longer than 1s then press_flag-- */
if(button->hold_cnt > 100)
{
button->press_flag--;
}
break;
}
default:
break;
}
}里面涉及到的宏定义和枚举，都在头文件内给出
/*
double click:
```___________``````````````___________````````````
min< <max <judge min< <max >judge
single click:
``````___________`````````
min< <max >judge
*/
#define LONG_PRESS_TIME 100
#define CLICK_MIN_TIME 5 /* if key press_cnt time less than this -> invalid click */
#define CLICK_MAX_TIME 20 /* if key press_cnt time more than this -> invalid click */
#define JUDGE_TIME 20 /* double click time space */
typedef enum
{
KEY_NULL,
KEY_DOWN,
KEY_PRESS,
KEY_UP,
}KeyActionType;
typedef enum
{
BUTTON_NULL,
BUTTON_SINGLE,
BUTTON_DOUBLE,
BUTTON_TRIPLE,
BUTTON_LONG_PRESS,
}ButtonActionType;串口重定向
打开usart.c
添加如下代码
int fputc(int ch, FILE *f)
{
HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xffff);
return ch;
}
int fgetc(FILE *f)
{
uint8_t ch = 0;
HAL_UART_Receive(&huart1, &ch, 1, 0xffff);
return ch;
}
主函数
在主循环内去读取键值，用定时器来周期扫描按键
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* Copyright (c) 2024 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "stdio.h"
#include "tim.h"
#include "key.h"
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_TIM2_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
Key_Config(); //配置按键
HAL_TIM_Base_Start_IT(&htim2); //开定时器
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
Key_Debug();
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
}
/* USER CODE BEGIN 4 */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
if(htim == &htim2)
{
Key_Scan(button);
Key_Scan(button+1);
Key_Scan(button+2);
Key_Scan(button+3);
}
}
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{
}
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
五、效果展示
按下按键，串口打印相应的按键号和键值
六、驱动附录
key.c
#include "key.h"
#include "stdio.h"
buttonType button[4];
void Key_Config()
{
button[0].GPIO_Port = K1_GPIO_Port;
button[0].GPIO_Pin = K1_Pin;
button[1].GPIO_Port = K2_GPIO_Port;
button[1].GPIO_Pin = K2_Pin;
button[2].GPIO_Port = K3_GPIO_Port;
button[2].GPIO_Pin = K3_Pin;
button[3].GPIO_Port = K4_GPIO_Port;
button[3].GPIO_Pin = K4_Pin;
}
void Key_ParaInit(buttonType* button)
{
button->high_cnt = 0;
button->hold_cnt = 0;
button->press_flag = 0;
button->release_flag = 0;
}
void Key_Scan(buttonType* button)
{
switch(button->key)
{
case KEY_NULL:
{
/* if falling edge captured */
if(HAL_GPIO_ReadPin(button->GPIO_Port,button->GPIO_Pin) == 0)
{
button->key = KEY_DOWN;
}
else if(HAL_GPIO_ReadPin(button->GPIO_Port,button->GPIO_Pin) == 1)
{
button->key = KEY_NULL;
}
/* if button is released ,high_time_count++ */
if(button->release_flag == 1)
{
button->high_cnt++;
}
/**********************judge***********************/
/* if high_time_count is longer than LONG_PRESS_TIME, consider BUTTON_LONG_PRESS */
if(button->hold_cnt > LONG_PRESS_TIME)
{
button->buttonAction = BUTTON_LONG_PRESS;
Key_ParaInit(button);
}
/* if high_time_count is shorter than LONG_PRESS_TIME,but longer than CLICK_MAX_TIME consider INVALID */
else if(button->hold_cnt < LONG_PRESS_TIME && button->hold_cnt > CLICK_MAX_TIME)
{
Key_ParaInit(button);
}
/*
only the latest press time is in range of [CLICK_MIN_TIME,CLICK_MAX_TIME] can be regarded valid
if high level time > JUDGE_TIME also means that over the JUDGE_TIME and still dont have button pushed
we can check the flag value to get button state now
*/
else if((button->high_cnt > JUDGE_TIME)&&(button->hold_cnt > CLICK_MIN_TIME && button->hold_cnt < CLICK_MAX_TIME))
{
if(button->press_flag ==1)
{
button->buttonAction = BUTTON_SINGLE;
}
else if(button->press_flag == 2)
{
button->buttonAction = BUTTON_DOUBLE;
}
else if(button->press_flag == 3)
{
button->buttonAction = BUTTON_TRIPLE;
}
Key_ParaInit(button);
}
break;
}
case KEY_DOWN:
{
button->key = KEY_PRESS;
/* as long as falling edge occurring,press_flag++ */
button->press_flag++;
button->release_flag = 0; /* means that the button has been pressed */
button->hold_cnt = 0; /* reset hold time count */
break;
}
case KEY_PRESS:
{
/* when button was kept pressed, hold count++ */
if(HAL_GPIO_ReadPin(button->GPIO_Port,button->GPIO_Pin) == 0)
{
button->key = KEY_PRESS;
button->hold_cnt++;
}
/* when button was released, change state */
else if(HAL_GPIO_ReadPin(button->GPIO_Port,button->GPIO_Pin) == 1)
{
button->key = KEY_UP;
}
break;
}
case KEY_UP:
{
button->key = KEY_NULL;
button->release_flag = 1; /* means that the button is released */
button->high_cnt = 0; /* reset hold time count */
/* if press time is longer than 1s then press_flag-- */
if(button->hold_cnt > 100)
{
button->press_flag--;
}
break;
}
default:
break;
}
}
void Key_Debug()
{
for(uint8_t i=0;i<4;i++)
{
switch(button[i].buttonAction)
{
case BUTTON_SINGLE:
{
button[i].buttonAction = BUTTON_NULL;
printf("%d->",i);
printf("BUTTON_SINGLE\r\n");
break;
}
case BUTTON_LONG_PRESS:
{
button[i].buttonAction = BUTTON_NULL;
printf("%d->",i);
printf("BUTTON_LONG_PRESS\r\n");
break;
}
case BUTTON_DOUBLE:
{
button[i].buttonAction = BUTTON_NULL;
printf("%d->",i);
printf("BUTTON_DOUBLE\r\n");
break;
}
case BUTTON_TRIPLE:
{
button[i].buttonAction = BUTTON_NULL;
printf("%d->",i);
printf("BUTTON_TRIPLE\r\n");
break;
}
case BUTTON_NULL:
{
button[i].buttonAction = BUTTON_NULL;
break;
}
default:
{
break;
}
}
}
}key.h
#ifndef KEY_H
#define KEY_H
#include "tim.h"
#include "main.h"
/*
double click:
```___________``````````````___________````````````
min< <max <judge min< <max >judge
single click:
``````___________`````````
min< <max >judge
*/
#define LONG_PRESS_TIME 100
#define CLICK_MIN_TIME 5 /* if key press_cnt time less than this -> invalid click */
#define CLICK_MAX_TIME 20 /* if key press_cnt time more than this -> invalid click */
#define JUDGE_TIME 20 /* double click time space */
typedef enum
{
KEY_NULL,
KEY_DOWN,
KEY_PRESS,
KEY_UP,
}KeyActionType;
typedef enum
{
BUTTON_NULL,
BUTTON_SINGLE,
BUTTON_DOUBLE,
BUTTON_TRIPLE,
BUTTON_LONG_PRESS,
}ButtonActionType;
typedef struct
{
GPIO_TypeDef * GPIO_Port; //按键端口
uint16_t GPIO_Pin; //按键PIN
KeyActionType key; //按键类型
uint16_t hold_cnt; //按压计数器
uint16_t high_cnt; //高电平计数器
uint8_t press_flag; //按压标志
uint8_t release_flag; //松手标志
ButtonActionType buttonAction; //按键键值
}buttonType;
extern buttonType button[4];
void Key_Scan(buttonType*);
void Key_Debug();
void Key_Config();
#endif作者：田甲
