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单片机长短按简单实现

1 原理

按键检测和处理的步骤如下：

1：定时扫描按键（使用定时器定时扫描，也可以用软件延时或者系统心跳之类的方式，总之能保证每次扫描间隔时间固定并且在一个较小的范围即可）。
2：扫描到有按键按下（通常是检测GPIO的电平状态来判断按键是否按下，具体情况需要结合实际硬件电路来看）。
3：开始计时，记录按键持续按下的时间。
4：若按下的时间达到了短按的时间（具体多长的时间为短按由自己定义），选择触发按键处理（按下即触发），或者先记录状态，等按键释放时再触发按键处理（弹起时触发）。
5：按键时间超过短按时间，继续计时。
6：按键时间达到长按时间（具体多长的时间为长按由自己定义），选择触发按键处理（按下即触发），或者先记录状态，等按键释放时再触发按键处理（弹起时触发）。

2 示例代码

该示例使用的GD32，共配置了4个按键，特点如下：

1：按键按下时电平为0，释放时为1。
2：短按时间为30ms。
3：长按时间为1s。
4：短按释放时触发按键处理。
5：长按按下时即触发按键处理。
6：按键扫描和按键处理均放在定时器中断服务函数，若按键处理的时间较长，建议分开操作（按键扫描还是放在中断，按键处理放在其他地方，以免长时间占用中断时间）。
7：按键处理我这里都是留空的，只用串口打印了一句话，表明已经触发了按键处理，具体处理什么东西看实际需求。

注：示例代码仅供参考，还需要按具体需求修改。

2.1 按键实现

key.c：

#include "key.h"
#include "main.h"key_t key1;
key_t key2;
key_t key3;
key_t key4;void timer_user_init(void);// 按键初始化
void key_user_init(void)
{/* enable the key clock */rcu_periph_clock_enable(KEY1_CLOCK);rcu_periph_clock_enable(KEY2_CLOCK);rcu_periph_clock_enable(KEY3_CLOCK);rcu_periph_clock_enable(KEY4_CLOCK);/* configure key gpio port */ gpio_init(KEY1_PORT, GPIO_MODE_IPU, GPIO_OSPEED_50MHZ, KEY1_PIN);gpio_init(KEY2_PORT, GPIO_MODE_IPU, GPIO_OSPEED_50MHZ, KEY2_PIN);gpio_init(KEY3_PORT, GPIO_MODE_IPU, GPIO_OSPEED_50MHZ, KEY3_PIN);gpio_init(KEY4_PORT, GPIO_MODE_IPU, GPIO_OSPEED_50MHZ, KEY4_PIN);timer_user_init();  // 启动定时器，定时扫描按键
}// 按键扫描
int key_scan(void)
{if(READ_KEY1_STATE == KEY_PRESSED && (key1.status == 0)){if(++key1.debounce > KEY_SHORT_PRESSED){// 短按key1.status = 1;// LOG("key1 short pressed.\n");}}else if(READ_KEY1_STATE == KEY_PRESSED && (key1.status == 1)){if(++key1.debounce > KEY_LONG_PRESSED){// 长按key1.status = 2;key1.debounce = 0;// LOG("key1 long pressed.\n");return KEY1_LONG_PRESSED;}}else if((READ_KEY1_STATE == KEY_RELEASED) && (key1.status > 0)){if(key1.status == 1){// 短按释放key1.status = 0;key1.debounce = 0;return KEY1_SHORT_PRESSED;}if(key1.status == 2){// 长按释放key1.status = 0;key1.debounce = 0;}}if(READ_KEY2_STATE == KEY_PRESSED && (key2.status == 0)){if(++key2.debounce > KEY_SHORT_PRESSED){// 短按key2.status = 1;}}else if(READ_KEY2_STATE == KEY_PRESSED && (key2.status == 1)){if(++key2.debounce > KEY_LONG_PRESSED){// 长按key2.status = 2;key2.debounce = 0;return KEY2_LONG_PRESSED;}}else if((READ_KEY2_STATE == KEY_RELEASED) && (key2.status > 0)){if(key2.status == 1){// 短按释放key2.status = 0;key2.debounce = 0;return KEY2_SHORT_PRESSED;}if(key2.status == 2){// 长按释放key2.status = 0;key2.debounce = 0;}}if(READ_KEY3_STATE == KEY_PRESSED && (key3.status == 0)){if(++key3.debounce > KEY_SHORT_PRESSED){// 短按key3.status = 1;}}else if(READ_KEY3_STATE == KEY_PRESSED && (key3.status == 1)){if(++key3.debounce > KEY_LONG_PRESSED){// 长按key3.status = 2;key3.debounce = 0;return KEY3_LONG_PRESSED;}}else if((READ_KEY3_STATE == KEY_RELEASED) && (key3.status > 0)){if(key3.status == 1){// 短按释放key3.status = 0;key3.debounce = 0;return KEY3_SHORT_PRESSED;}if(key3.status == 2){// 长按释放key3.status = 0;key3.debounce = 0;}}if(READ_KEY4_STATE == KEY_PRESSED && (key4.status == 0)){if(++key4.debounce > KEY_SHORT_PRESSED){// 短按key4.status = 1;}}else if(READ_KEY4_STATE == KEY_PRESSED && (key4.status == 1)){if(++key4.debounce > KEY_LONG_PRESSED){// 长按key4.status = 2;key4.debounce = 0;return KEY4_LONG_PRESSED;}}else if((READ_KEY4_STATE == KEY_RELEASED) && (key4.status > 0)){if(key4.status == 1){// 短按释放key4.status = 0;key4.debounce = 0;return KEY4_SHORT_PRESSED;}if(key4.status == 2){// 长按释放key4.status = 0;key4.debounce = 0;}}return -1;
}// 按键处理
void key_handle(void)
{static uint8_t key_state;uint8_t i;static uint8_t step = 0;key_state = key_scan();  // 按键扫描if(key_state == KEY1_SHORT_PRESSED){// 按键1短按LOG("key1 short pressed.\n");}else if(key_state == KEY1_LONG_PRESSED){// 按键1长按LOG("key1 long pressed.\n");}else if(key_state == KEY2_SHORT_PRESSED){// 按键2短按LOG("key2 short pressed.\n");}else if(key_state == KEY2_LONG_PRESSED){// 按键2长按LOG("key2 long pressed.\n");}else if(key_state == KEY3_SHORT_PRESSED){// 按键3短按LOG("key3 short pressed.\n");}else if(key_state == KEY3_LONG_PRESSED){// 按键3长按LOG("key3 long pressed.\n");}else if(key_state == KEY4_SHORT_PRESSED){// 按键4短按LOG("key4 short pressed.\n");}else if(key_state == KEY4_LONG_PRESSED){// 按键4长按LOG("key4 long pressed.\n");}
}/********************** 定时器配置，用于定时扫描按键 *************************/ 
void TIMER2_IRQHandler(void)
{if(SET == timer_interrupt_flag_get(TIMER2, TIMER_INT_UP)){/* clear channel 0 interrupt bit */timer_interrupt_flag_clear(TIMER2, TIMER_INT_UP);key_handle();  // 按键扫描并处理}
}void nvic_config(void)
{nvic_irq_enable(TIMER2_IRQn, 0, 0);
}void timer_config(void)
{/* ----------------------------------------------------------------------------TIMER2 Configuration: TIMER2CLK = SystemCoreClock/18000 = 10KHz, the period is 1s(10/10000 = 1s).---------------------------------------------------------------------------- */timer_parameter_struct timer_initpara;/* enable the peripherals clock */rcu_periph_clock_enable(RCU_TIMER2);/* deinit a TIMER */timer_deinit(TIMER2);/* initialize TIMER init parameter struct */timer_struct_para_init(&timer_initpara);/* TIMER2 configuration */timer_initpara.prescaler         = 18000 - 1;           // 180MHz / 18000 = 10kHztimer_initpara.alignedmode       = TIMER_COUNTER_EDGE;timer_initpara.counterdirection  = TIMER_COUNTER_UP;timer_initpara.period            = 10 - 1;             // 10 * 0.01ms = 1mstimer_initpara.clockdivision     = TIMER_CKDIV_DIV1;timer_init(TIMER2, &timer_initpara);/* enable the TIMER interrupt */timer_interrupt_enable(TIMER2, TIMER_INT_UP);/* enable a TIMER */timer_enable(TIMER2);
}void timer_user_init(void)
{/* configure the TIMER peripheral */timer_config();/* configure the TIMER2 interrupt */nvic_config();
}

key.h：

#ifndef __KEY_H
#define __KEY_H#include "gd32e50x.h"
#include "gd32e50x_gpio.h"#define KEY1_SHORT_PRESSED   0
#define KEY2_SHORT_PRESSED   1
#define KEY3_SHORT_PRESSED   2
#define KEY4_SHORT_PRESSED   3
#define KEY1_LONG_PRESSED    4
#define KEY2_LONG_PRESSED    5
#define KEY3_LONG_PRESSED    6
#define KEY4_LONG_PRESSED    7#define KEY_PRESSED          0      // 按下时电平为0
#define KEY_RELEASED         1      // 按下时电平为1
#define KEY_SHORT_PRESSED    30     // 1ms x 30 = 30ms
#define KEY_LONG_PRESSED     1000   // 1ms x 1000 = 1s#define KEY1_CLOCK       RCU_GPIOB
#define KEY1_PORT        GPIOB
#define KEY1_PIN         GPIO_PIN_12
#define KEY2_CLOCK       RCU_GPIOB
#define KEY2_PORT        GPIOB
#define KEY2_PIN         GPIO_PIN_13
#define KEY3_CLOCK       RCU_GPIOB
#define KEY3_PORT        GPIOB
#define KEY3_PIN         GPIO_PIN_14
#define KEY4_CLOCK       RCU_GPIOB
#define KEY4_PORT        GPIOB
#define KEY4_PIN         GPIO_PIN_15#define READ_KEY1_STATE  gpio_input_bit_get(KEY1_PORT, KEY1_PIN)
#define READ_KEY2_STATE  gpio_input_bit_get(KEY2_PORT, KEY2_PIN)
#define READ_KEY3_STATE  gpio_input_bit_get(KEY3_PORT, KEY3_PIN)
#define READ_KEY4_STATE  gpio_input_bit_get(KEY4_PORT, KEY4_PIN)typedef struct
{uint16_t debounce;uint8_t status;
} key_t;void key_user_init(void);
int key_scan(void);#endif

main.c：

#include "main.h"
#include "uart.h"
#include "key.h"int main(void)
{// systick_config();uart_user_init();key_user_init();printf("app init success.\n");while(1){}
}

mian.h：

#ifndef MAIN_H
#define MAIN_H#include "gd32e50x.h"
#include "gd32e50x_rcu.h"
#include "gd32e50x_gpio.h"
#include "systick.h"
#include "uart.h"#define UART_DEBUG#ifdef UART_DEBUG#define DEBUG(format, ...) printf(format, ##__VA_ARGS__)#define LOG  printf
#else#define DEBUG(format, ...)#define LOG(format, ...) 
#endif#endif /* MAIN_H */

3 测试log

4 其他实现方式

详见我之前的博客：以STM32为例，实现按键的短按和长按