u8 KEY_Scan(u8 mode) { static u8 key_up=1; if(mode)key_up=1; if(key_up&&(KEY0==0||KEY1==0||WK_UP==1)) { delay_ms(10); key_up=0; if(KEY0==0)return KEY0_PRES; else if(KEY1==0)return KEY1_PRES; else if(WK_UP==1)return WKUP_PRES; }else if(KEY0==1&&KEY1==1&&WK_UP==0)key_up=1; return 0;/ }

) { //检测按键是否按下 if(KEY0==0||KEY1==0||KEY2==0||WK_UP==1) { //延时消抖 delay_ms(10); key_up=0; if(KEY0==0)return KEY0_PRES; else if(KEY1==0)return KEY1_PRES; else if(KEY2==0)return KEY2_PRES; else if(WK_UP==1)return WKUP_PRES; } } else { //检测按键是否松开 if(KEY0==1&&KEY1==1&&KEY2==1&&WK_UP==0)key_up=1; } return 0;// 无按键按下}

Explanation:

This code is for detecting keypad input. It takes in a parameter 'mode', which is used to indicate if the program is in initialization mode (mode = 1). The program contains a debounce mechanism to avoid false inputs caused by the user pressing the key multiple times.

The function first checks if the key has been released (key_up == 1). If so, it checks if any key (KEY0, KEY1, KEY2, or WK_UP) has been pressed. If a key has been pressed, the program waits for 10 ms to debounce, and then returns the corresponding signal indicating which key has been pressed (KEY0_PRES, KEY1_PRES, KEY2_PRES, or WKUP_PRES).

If no key is pressed, the program checks if the key has been released, and sets key_up to 1 if it has. It then returns 0 to indicate no key has been pressed.