单片机按键扫描程序，可以单击、双击、长按，使用状态机，无延时，不阻塞。

• 根据按下时的时长、间隔来判断是否是连按或者长按。
• 当连按间隔很短时，计录连按次数
• 超过连接间隔时，回报按下次数
• 根据按键次数自行判断是单击、双击、三击、四击。。。最多记录15击。

结构体版：

#define KEY_CHANNEL_COUNT (6 + 8 + 8)
struct keyInfo
{uint8_t act : 4;       // 按了多少次，最多连按15次uint8_t down : 1;      // 按下了uint8_t up : 1;        // 松开了uint8_t longPress : 1; // 长按了uint8_t io : 1;        // 按键IO状态uint8_t intervalTime;  // 连按间隔时间uint8_t holdTime;      // 长按时间uint8_t duration;      // 按键次数保持时间，超过后，act清零
};
struct keyInfo keyValues[KEY_CHANNEL_COUNT] = {0};void button_trace_handle(void *p)
{static uint32_t lastTime = 0;const uint8_t KEYSCAN_INTERVAL_TIME = 10; // 按键扫描间隔时间const uint8_t LONG_PRESS_TIME = 100;  // 长按多久生效, 实际时间为,下面同理 LONG_PRESS_TIME * KEYSCAN_INTERVAL_TIMEconst uint8_t INTERVAL_TIME_SET = 20; // 两次按键检测超时const uint8_t ANTI_SHAKE_TIME = 2;    // 按键防抖检测超时/*** @brief 需要实现millis()函数,系统毫秒计时器。* */if (millis()> lastTime + KEYSCAN_INTERVAL_TIME){lastTime = millis();        }else{return;}/**给按键IO赋值, 有多个按键就传多少个, 自己实现ic_read函数 */for (uint8_t i = 0; i < KEY_CHANNEL_COUNT; i++){keyValues[i].io = io_read(i);}for (uint8_t i = 0; i < KEY_CHANNEL_COUNT; i++){if (keyValues[i].io)//按下了{if (keyValues[i].holdTime < LONG_PRESS_TIME){keyValues[i].holdTime++;if (keyValues[i].holdTime >= ANTI_SHAKE_TIME)//防抖{keyValues[i].down = 1;keyValues[i].intervalTime = INTERVAL_TIME_SET;}}else //长按了，会一直标记，直到松开{keyValues[i].longPress = 1;}}else{//松开了keyValues[i].holdTime = 0;keyValues[i].longPress = 0;if (keyValues[i].down)//按下过了{if (!keyValues[i].longPress)//不是长按keyValues[i].act++;//按下次数+1keyValues[i].down = 0;}if (keyValues[i].intervalTime)//连按超时{keyValues[i].intervalTime--;if (keyValues[i].intervalTime == 1){LOG_D("key[%d] act:%d", i, keyValues[i].act);//打印哪个按键按了多少次keyValues[i].duration = 10;}}}if (keyValues[i].duration >= 1){keyValues[i].duration--;if (keyValues[i].duration == 1)//按键次数保持时间到{keyValues[i].act = 0;}}}
}

无结构体版，更方便移到51单片机上

#define KEY_DOWN_MASK  0X80/**按下标记*/
#define KEY_LONG_PRESS_MASK  0X40/**长按标记 */
#define KEY_TIMEOUT_MASK  0X10/**超时标志，此时返回按键值*/
#define KEY_TIEMES_MASK  0X0F/**按了多少次 */
#define KEY_VALUE(x) (0x0001<<(x))#define KEY_COUNTS 5void keyScanPro()
{const uint8_t SHORT_PRESS_TIME = 25;const uint16_t LONG_PRESS_TIME = 150;const uint8_t IS_KEY_DOWN = 0X80;/**按下了 */const uint8_t IS_LONG_PRESS = 0X40;/**长按了 */const uint8_t IS_TIME_OUT = 0X10;/**退好久没按 */static uint8_t keyActionHold = 0;static uint8_t pressTimesRecord[KEY_COUNTS] = { 0 };static uint8_t pressTime[KEY_COUNTS] = { 0 };static uint16_t longPressTime[KEY_COUNTS] = { 0 };const uint16_t channel_keyScan_map[KEY_COUNTS] = { DEF_SET_BIT0,DEF_SET_BIT1,DEF_SET_BIT2,DEF_SET_BIT3,DEF_SET_BIT4 };/**A,B,C,D,E,F,G,H,I,J,K,L对就的键值*/uint8_t i;keyValue = KP; keyValue <<= 1;keyValue |= !K1; keyValue <<= 1;keyValue |= !K2; keyValue <<= 1;keyValue |= !K3; keyValue <<= 1;keyValue |= !K4;if (keyValue != keyValuePre){ResetSystemShutdownCountdown();keyValuePre = keyValue;}// LOG("keyValue:%d\n",(int)keyValue);if (keyAction){if (keyActionHold++ > 100){keyActionHold = 0;keyAction = 0;}}for (i = 0; i < KEY_COUNTS; i++){if (keyValue & channel_keyScan_map[i]){//按下了if (longPressTime[i] < LONG_PRESS_TIME){longPressTime[i]++;pressTime[i] = SHORT_PRESS_TIME;pressTimesRecord[i] |= IS_KEY_DOWN;}else{pressTimesRecord[i] |= IS_LONG_PRESS;pressTimesRecord[i] |= IS_TIME_OUT;pressTimesRecord[i] &= ~IS_KEY_DOWN; //取消标记高位keyLongPress |= 1 << i;keyAction |= ((i + 1) << 8);if (keyValue & PWR_KEY_VALUE){LOG("System shutting down ...");SYS_PWR_SHUTDOWN();while (1);}LOG("long press:%d\n", (int)keyLongPress);// if (pwrKeyLongPressCb) pwrKeyLongPressCb();// else pwrKeyLongPressCbDefault();}}else{//松开了longPressTime[i] = 0;keyLongPress &= ~(1 << i);if (pressTimesRecord[i] & IS_KEY_DOWN){//高位标记过，即按下过keyActionHold = 0;pressTimesRecord[i] &= ~IS_KEY_DOWN; //取消标记高位if ((pressTimesRecord[i] & KEY_TIEMES_MASK) < 15){uint8_t ptc = 0;pressTimesRecord[i]++;ptc = pressTimesRecord[i] & KEY_TIEMES_MASK;ptc = ptc > 7 ? 7 : ptc;// speaker_out(music_note_freq[ptc], 100);}}if (pressTime[i] > 0){if (pressTime[i] == 1){pressTimesRecord[i] |= IS_TIME_OUT;//BIT4 为检测时间到}pressTime[i]--;}if (pressTimesRecord[i] & IS_TIME_OUT){if (pressTimesRecord[i] & IS_LONG_PRESS){// rt_kprintf("Long press:%d \n", i);pressTimesRecord[i] &= ~IS_LONG_PRESS;}else if (pressTimesRecord[i] & KEY_TIEMES_MASK){uint8_t ptc = pressTimesRecord[i] & KEY_TIEMES_MASK;keyAction |= (i + 1) << 4 | ptc;LOG("keyAction:%x\n", (int)keyAction);// struct pwrKeyActList* p;// p = &pwrKeyActListHead;// do {//     // LOG_D("P:0x%08X", p);//     if (p->cb)//     {//         p->cb(ptc);//     }//     p = p->next;// } while (p);}// LOG("Press:%d - %d\n", (int)i, (int)(pressTimesRecord[i] & KEY_TIEMES_MASK));;pressTimesRecord[i] = 0;}}}
}