一、工程簡介
MultiButton 是一個小巧簡單易用的事件驅(qū)動型按鍵驅(qū)動模塊。
Github地址：https://github.com/0x1abin/MultiButton
這個項目非常精簡，只有兩個文件：
?。?）可無限擴(kuò)展按鍵；
?。?）按鍵事件的回調(diào)異步處理方式可以簡化程序結(jié)構(gòu)，去除冗余的按鍵處理硬編碼，讓按鍵業(yè)務(wù)邏輯更清晰。
通過此工程可以學(xué)習(xí)到以下知識點：
?。?）按鍵各種類型事件；
?。?）狀態(tài)機(jī)的思想；
?。?）單向鏈表語法。
工程支持如下的按鍵事件：
? MultiButton 的按鍵狀態(tài)及軟件流程圖：
?二、工程代碼分析
注：在使用源碼工程時稍微修改了兩個點，后續(xù)貼出修改后的完整代碼，有需要查看修改的同學(xué)可以將源碼工程下載后進(jìn)行對比，修改的點如下：
?。?）將按鍵時間的相關(guān)參數(shù)通過接口定義進(jìn)行初始化；
（2）修改按鍵長按期間一直觸發(fā)事件為真正的長按按鍵定時觸發(fā)事件。
在頭文件multi_button.h中包括：
（1）定義了按鍵時間相關(guān)參數(shù)；
（2）定義了按鍵的事件類型；
（3）定義按鍵鏈表結(jié)構(gòu)體，這里使用了位域操作，解決字節(jié)的存儲空間問題。
1 #ifndef _MULTI_BUTTON_H_ 2 #define _MULTI_BUTTON_H_ 3 4 #include <stdint.h> 5 #include <string.h> 6 7 typedef struct ButtonPara { 8 uint8_t ticks_interval; 9 uint8_t debounce_ticks; 10 uint16_t short_ticks; 11 uint16_t long_ticks; 12 }ButtonPara; 13 14 typedef void (*BtnCallback)(void*); 15 16 typedef enum { 17 PRESS_DOWN = 0, 18 PRESS_UP, 19 PRESS_REPEAT, 20 SINGLE_CLICK, 21 DOUBLE_CLICK, 22 LONG_PRESS_START, 23 LONG_PRESS_HOLD, 24 number_of_event, 25 NONE_PRESS 26 }PressEvent; 27 28 typedef struct Button { 29 uint16_t ticks; 30 uint8_t repeat : 4; 31 uint8_t event : 4; 32 uint8_t state : 3; 33 uint8_t debounce_cnt : 3; 34 uint8_t active_level : 1; 35 uint8_t button_level : 1; 36 uint8_t button_id; 37 uint8_t (*hal_button_Level)(uint8_t button_id_); 38 BtnCallback cb[number_of_event]; 39 struct Button* next; 40 }Button; 41 42 #ifdef __cplusplus 43 extern "C" { 44 #endif 45 void button_para_init(struct ButtonPara para); 46 void button_init(struct Button* handle, uint8_t(*pin_level)(uint8_t), uint8_t active_level, uint8_t button_id); 47 void button_attach(struct Button* handle, PressEvent event, BtnCallback cb); 48 PressEvent get_button_event(struct Button* handle); 49 int button_start(struct Button* handle); 50 void button_stop(struct Button* handle); 51 void button_ticks(void); 52 53 #ifdef __cplusplus 54 } 55 #endif 56 57 #endif
在源碼文件multi_button.c中包括：
（1）對按鍵時間參數(shù)進(jìn)行初始化；
?。?）對按鍵對象結(jié)構(gòu)體進(jìn)行初始化，初始化成員包括按鍵句柄，綁定GPIO電平讀取函數(shù)，設(shè)置有效觸發(fā)電平；
（3）初始化按鍵完成之后，進(jìn)行按鍵綁定操作，將綁定按鍵結(jié)構(gòu)體成員，按鍵觸發(fā)事件，按鍵回調(diào)函數(shù)；
?。?）按鍵啟動：也就是將按鍵加入鏈表當(dāng)中，啟動按鍵。這里選擇的插入方式是頭部插入法，在鏈表的頭部插入按鍵節(jié)點，效率高，時間復(fù)雜度為O(1)；
?。?）按鍵刪除：將按鍵從當(dāng)前鏈表中刪除。使用到了二級指針刪除一個按鍵元素。與鏈表中成員刪除方法相同；
?。?）按鍵滴答函數(shù)：每間隔Nms觸發(fā)一次按鍵事件，驅(qū)動狀態(tài)機(jī)運(yùn)行；
?。?）讀取當(dāng)前引腳的狀態(tài)，獲取按鍵當(dāng)前屬于哪種狀態(tài)；
?。?）按鍵處理核心函數(shù)，驅(qū)動狀態(tài)機(jī)。
1 #include "multi_button.h" 2 3 #define EVENT_CB(ev) if(handle->cb[ev])handle->cb[ev]((void*)handle) 4 #define PRESS_REPEAT_MAX_NUM 15 /*!< The maximum value of the repeat counter */ 5 6 static struct ButtonPara buttonpara; 7 //button handle list head. 8 static struct Button* head_handle = NULL; 9 10 static void button_handler(struct Button* handle); 11 12 13 void button_para_init(struct ButtonPara para) 14 { 15 buttonpara.ticks_interval = para.ticks_interval; 16 buttonpara.debounce_ticks = para.debounce_ticks; 17 buttonpara.short_ticks = para.short_ticks; 18 buttonpara.long_ticks = para.long_ticks; 19 } 20 /** 21 * @brief Initializes the button struct handle. 22 * @param handle: the button handle struct. 23 * @param pin_level: read the HAL GPIO of the connected button level. 24 * @param active_level: pressed GPIO level. 25 * @param button_id: the button id. 26 * @retval None 27 */ 28 void button_init(struct Button* handle, uint8_t(*pin_level)(uint8_t), uint8_t active_level, uint8_t button_id) 29 { 30 memset(handle, 0, sizeof(struct Button)); 31 handle->event = (uint8_t)NONE_PRESS; 32 handle->hal_button_Level = pin_level; 33 handle->button_level = handle->hal_button_Level(button_id); 34 handle->active_level = active_level; 35 handle->button_id = button_id; 36 } 37 38 /** 39 * @brief Attach the button event callback function. 40 * @param handle: the button handle struct. 41 * @param event: trigger event type. 42 * @param cb: callback function. 43 * @retval None 44 */ 45 void button_attach(struct Button* handle, PressEvent event, BtnCallback cb) 46 { 47 handle->cb[event] = cb; 48 } 49 50 /** 51 * @brief Inquire the button event happen. 52 * @param handle: the button handle struct. 53 * @retval button event. 54 */ 55 PressEvent get_button_event(struct Button* handle) 56 { 57 return (PressEvent)(handle->event); 58 } 59 60 /** 61 * @brief Button driver core function, driver state machine. 62 * @param handle: the button handle struct. 63 * @retval None 64 */ 65 static void button_handler(struct Button* handle) 66 { 67 uint8_t read_gpio_level = handle->hal_button_Level(handle->button_id); 68 69 //ticks counter working.. 70 if((handle->state) > 0) handle->ticks++; 71 72 /*------------button debounce handle---------------*/ 73 if(read_gpio_level != handle->button_level) { //not equal to prev one 74 //continue read 3 times same new level change 75 if(++(handle->debounce_cnt) >= buttonpara.debounce_ticks) { 76 handle->button_level = read_gpio_level; 77 handle->debounce_cnt = 0; 78 } 79 } else { //level not change ,counter reset. 80 handle->debounce_cnt = 0; 81 } 82 83 /*-----------------State machine-------------------*/ 84 switch (handle->state) { 85 case 0: 86 if(handle->button_level == handle->active_level) { //start press down 87 handle->event = (uint8_t)PRESS_DOWN; 88 EVENT_CB(PRESS_DOWN); 89 handle->ticks = 0; 90 handle->repeat = 1; 91 handle->state = 1; 92 } else { 93 handle->event = (uint8_t)NONE_PRESS; 94 } 95 break; 96 97 case 1: 98 if(handle->button_level != handle->active_level) { //released press up 99 handle->event = (uint8_t)PRESS_UP; 100 EVENT_CB(PRESS_UP); 101 handle->ticks = 0; 102 handle->state = 2; 103 } else if(handle->ticks > buttonpara.long_ticks) { 104 handle->event = (uint8_t)LONG_PRESS_START; 105 EVENT_CB(LONG_PRESS_START); 106 handle->state = 5; 107 } 108 break; 109 110 case 2: 111 if(handle->button_level == handle->active_level) { //press down again 112 handle->event = (uint8_t)PRESS_DOWN; 113 EVENT_CB(PRESS_DOWN); 114 if(handle->repeat != PRESS_REPEAT_MAX_NUM) { 115 handle->repeat++; 116 } 117 EVENT_CB(PRESS_REPEAT); // repeat hit 118 handle->ticks = 0; 119 handle->state = 3; 120 } else if(handle->ticks > buttonpara.short_ticks) { //released timeout 121 if(handle->repeat == 1) { 122 handle->event = (uint8_t)SINGLE_CLICK; 123 EVENT_CB(SINGLE_CLICK); 124 } else if(handle->repeat == 2) { 125 handle->event = (uint8_t)DOUBLE_CLICK; 126 EVENT_CB(DOUBLE_CLICK); // repeat hit 127 } 128 handle->state = 0; 129 } 130 break; 131 132 case 3: 133 if(handle->button_level != handle->active_level) { //released press up 134 handle->event = (uint8_t)PRESS_UP; 135 EVENT_CB(PRESS_UP); 136 if(handle->ticks < buttonpara.short_ticks) { 137 handle->ticks = 0; 138 handle->state = 2; //repeat press 139 } else { 140 handle->state = 0; 141 } 142 } else if(handle->ticks > buttonpara.short_ticks) { // SHORT_TICKS < press down hold time < LONG_TICKS 143 handle->state = 1; 144 } 145 break; 146 147 case 5: 148 if(handle->button_level == handle->active_level) { 149 //continue hold trigger 150 if(handle->ticks > buttonpara.long_ticks) { 151 handle->event = (uint8_t)LONG_PRESS_HOLD; 152 EVENT_CB(LONG_PRESS_HOLD); 153 handle->ticks = 0; 154 } 155 } else { //released 156 handle->event = (uint8_t)PRESS_UP; 157 EVENT_CB(PRESS_UP); 158 handle->state = 0; //reset 159 } 160 break; 161 default: 162 handle->state = 0; //reset 163 break; 164 } 165 } 166 167 /** 168 * @brief Start the button work, add the handle into work list. 169 * @param handle: target handle struct. 170 * @retval 0: succeed. -1: already exist. 171 */ 172 int button_start(struct Button* handle) 173 { 174 struct Button* target = head_handle; 175 while(target) { 176 if(target == handle) return -1; //already exist. 177 target = target->next; 178 } 179 handle->next = head_handle; 180 head_handle = handle; 181 return 0; 182 } 183 184 /** 185 * @brief Stop the button work, remove the handle off work list. 186 * @param handle: target handle struct. 187 * @retval None 188 */ 189 void button_stop(struct Button* handle) 190 { 191 struct Button** curr; 192 for(curr = &head_handle; *curr; ) { 193 struct Button* entry = *curr; 194 if(entry == handle) { 195 *curr = entry->next; 196 // free(entry); 197 return;//glacier add 2021-8-18 198 } else { 199 curr = &entry->next; 200 } 201 } 202 } 203 204 /** 205 * @brief background ticks, timer repeat invoking interval 5ms. 206 * @param None. 207 * @retval None 208 */ 209 void button_ticks(void) 210 { 211 struct Button* target; 212 for(target=head_handle; target; target=target->next) { 213 button_handler(target); 214 } 215 }
三、工程代碼應(yīng)用
以在freertos中應(yīng)用為例，包括：
?。?）按鍵對象的定義及時間參數(shù)定義；
?。?）按鍵回調(diào)函數(shù)包括讀取按鍵電平函數(shù)和各按鍵事件處理函數(shù)的編寫；
（3）按鍵初始化操作及啟動按鍵功能；
?。?）在while(1)中添加按鍵滴答函數(shù)。
1 #define TICKS_INTERVAL 5 //按鍵狀態(tài)輪詢周期，單位ms 2 #define DEBOUNCE_TICKS 3 //MAX 7 (0 ~ 7) 去抖時間次數(shù)，此為15ms/TICKS_INTERVAL=3次 3 #define SHORT_TICKS (300 /TICKS_INTERVAL) //短按時間次數(shù)，300ms/TICKS_INTERVAL 4 #define LONG_TICKS (2000 /TICKS_INTERVAL) //長按時間次數(shù)，2000ms/TICKS_INTERVAL 5 6 enum Button_IDs { 7 btn1_id, 8 btn2_id, 9 btn3_id, 10 }; 11 struct ButtonPara btnpara = {TICKS_INTERVAL, DEBOUNCE_TICKS, SHORT_TICKS, LONG_TICKS}; 12 struct Button btn1; 13 struct Button btn2; 14 struct Button btn3; 15 16 //According to your need to modify the constants. 17 18 uint8_t read_button_GPIO(uint8_t button_id) 19 { 20 // you can share the GPIO read function with multiple Buttons 21 switch(button_id) 22 { 23 case btn1_id: 24 return GPIO_ReadInputDataBit(GPIOE,GPIO_Pin_4); 25 case btn2_id: 26 return GPIO_ReadInputDataBit(GPIOE,GPIO_Pin_3); 27 case btn3_id: 28 return GPIO_ReadInputDataBit(GPIOE,GPIO_Pin_2); 29 default: 30 return 0; 31 } 32 } 33 34 void BTN1_PRESS_DOWN_Handler(void* btn) 35 { 36 printf("BTN1_PRESS_DOWN_Handler!\r\n"); 37 } 38 39 void BTN1_PRESS_UP_Handler(void* btn) 40 { 41 printf("BTN1_PRESS_UP_Handler!\r\n"); 42 } 43 44 void BTN1_PRESS_REPEAT_Handler(void* btn) 45 { 46 printf("BTN1_PRESS_REPEAT_Handler, repeatcount = %d!\r\n",btn1.repeat); 47 } 48 49 void BTN1_SINGLE_Click_Handler(void* btn) 50 { 51 printf("BTN1_SINGLE_Click_Handler!\r\n"); 52 } 53 54 void BTN1_DOUBLE_Click_Handler(void* btn) 55 { 56 printf("BTN1_DOUBLE_Click_Handler!\r\n"); 57 } 58 59 void BTN1_LONG_PRESS_START_Handler(void* btn) 60 { 61 printf("BTN1_LONG_PRESS_START_Handler!\r\n"); 62 } 63 64 void BTN1_LONG_PRESS_HOLD_Handler(void* btn) 65 { 66 printf("BTN1_LONG_PRESS_HOLD_Handler!\r\n"); 67 } 68 69 void BTN2_SINGLE_Click_Handler(void* btn) 70 { 71 printf("BTN2_SINGLE_Click_Handler!\r\n"); 72 } 73 74 void BTN2_DOUBLE_Click_Handler(void* btn) 75 { 76 printf("BTN2_DOUBLE_Click_Handler!\r\n"); 77 } 78 79 void BTN3_LONG_PRESS_START_Handler(void* btn) 80 { 81 printf("BTN3_LONG_PRESS_START_Handler!\r\n"); 82 } 83 84 void BTN3_LONG_PRESS_HOLD_Handler(void* btn) 85 { 86 printf("BTN3_LONG_PRESS_HOLD_Handler!\r\n"); 87 } 88 89 int main(void) 90 { 91 button_para_init(btnpara); 92 button_init(&btn1, read_button_GPIO, 0, btn1_id); 93 button_init(&btn2, read_button_GPIO, 0, btn2_id); 94 button_init(&btn3, read_button_GPIO, 0, btn3_id); 95 96 button_attach(&btn1, PRESS_DOWN, BTN1_PRESS_DOWN_Handler); 97 button_attach(&btn1, PRESS_UP, BTN1_PRESS_UP_Handler); 98 button_attach(&btn1, PRESS_REPEAT, BTN1_PRESS_REPEAT_Handler); 99 button_attach(&btn1, SINGLE_CLICK, BTN1_SINGLE_Click_Handler); 100 button_attach(&btn1, DOUBLE_CLICK, BTN1_DOUBLE_Click_Handler); 101 button_attach(&btn1, LONG_PRESS_START, BTN1_LONG_PRESS_START_Handler); 102 button_attach(&btn1, LONG_PRESS_HOLD, BTN1_LONG_PRESS_HOLD_Handler); 103 104 button_attach(&btn2, PRESS_REPEAT, BTN2_PRESS_REPEAT_Handler); 105 button_attach(&btn2, SINGLE_CLICK, BTN2_SINGLE_Click_Handler); 106 button_attach(&btn2, DOUBLE_CLICK, BTN2_DOUBLE_Click_Handler); 107 108 button_attach(&btn3, LONG_PRESS_START, BTN3_LONG_PRESS_START_Handler); 109 button_attach(&btn3, LONG_PRESS_HOLD, BTN3_LONG_PRESS_HOLD_Handler); 110 111 button_start(&btn1); 112 button_start(&btn2); 113 button_start(&btn3); 114 115 116 xTaskCreate((TaskFunction_t )key_task, 117 (const char* )"key_task", 118 (uint16_t )KEY_STK_SIZE, 119 (void* )NULL, 120 (UBaseType_t )KEY_TASK_PRIO, 121 (TaskHandle_t* )&KeyTask_Handler); 122 vTaskStartScheduler(); 123 } 124 125 126 void key_task(void *pvParameters) 127 { 128 while(1) 129 { 130 button_ticks(); 131 vTaskDelay(5); //5ms周期輪詢 132 } 133 }
四、思考
使用中有如下問題值得思考：
?。?）組合鍵和矩陣按鍵如何實現(xiàn)？
在函數(shù)uint8_t read_button_GPIO(uint8_t button_id)中進(jìn)行組合鍵和矩陣按鍵返回值的自定義。
?。?）多個按鍵時，按鍵參數(shù)進(jìn)行區(qū)分？
去抖時間，短按時間，長按時間可以放在一個數(shù)組中區(qū)分，各個按鍵定義各自的參數(shù)。
?。?）現(xiàn)在按鍵事件較多的情況時，需要多個綁定的事件函數(shù)？
可以將按鍵事件函數(shù)統(tǒng)一放在一個數(shù)組中進(jìn)行初始化注冊。
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