#include <stdio.h>
#include <absacc.h>
#include <./Atmel/at89x52.h>
extern void start_t2imer(void);
unsigned char scankey;
bit Timerout=0;
bit keypress;
#define KR0    P1_0
#define KR1    P1_1
#define KR2    P1_2
#define KR3    P1_3
#define KC0    P1_4
#define KC1    P1_5
#define KC2    P1_6
#define KC3    P1_7
#define KBD_PORT  P1
#define FSM_INIT    0X00
#define FSM_WAIT_PRESS  0X01
#define FSM_VERFY1      0X02
#define FSM_VERFY2      0X03
#define FSM_WAIT_RELESE 0X04
#define KBD_VAL_VAILD   0X80
main(){
	unsigned char fsm_key=0;
	unsigned char kbd_col;
	unsigned char kbd_row;
	unsigned char key_val;
	IE=0X40;
	start_t2imer();
	EA=1;       /* Enable interrupts */
	while(1){
		if(Timerout){
			Timerout=0;
			switch(fsm_key){
				case FSM_INIT:
					KR0=1;
					KR1=1;
					KR2=1;
					KR3=1;
					fsm_key=FSM_WAIT_PRESS;
					break;
				case FSM_WAIT_PRESS:
					if(keypress){
						key_val=0;
						if(KC0){
							KC0=1;
							kbd_col=1;
						}
						else if(KC1){
							KC1=1;
							kbd_col=2;
						}
						else if(KC2){
							KC2=1;
							kbd_col=3;
						}
						else if(KC3){
							KC3=1;
							kbd_col=4;
						}
						else{
							fsm_key=FSM_INIT;
						}

						kbd_row =KBD_PORT;
	                    kbd_row >>=4;
						if(kbd_row){
							if(KR0){
								kbd_row=0;
								fsm_key=FSM_VERFY1;
							}
							else if(KR1){
								kbd_row=4;
								fsm_key=FSM_VERFY1;
							}
							else if(KR2){
								kbd_row=8;
								fsm_key=FSM_VERFY1;
							}
							else if(KR3){
								kbd_row=12;
								fsm_key=FSM_VERFY1;
							}
							else{
								fsm_key=FSM_INIT;
							}
						}
						else{
							fsm_key=FSM_INIT;
						}
					}
					break;
				case FSM_VERFY1:
					switch(kbd_row){
						case 0:
							if(KR0)	fsm_key=FSM_VERFY2;
							else fsm_key=FSM_INIT;
							break;
						case 4:
							if(KR1)	fsm_key=FSM_VERFY2;
							else fsm_key=FSM_INIT;
							break;
						case 8:
							if(KR2)	fsm_key=FSM_VERFY2;
							else fsm_key=FSM_INIT;
							break;
						case 12:
							if(KR3)	fsm_key=FSM_VERFY2;
							else fsm_key=FSM_INIT;
							break;
						default:
							fsm_key=FSM_INIT;
							break;
					}
					break;
				case FSM_VERFY2:
					switch(kbd_row){
						case 0:
							if(KR0)	key_val=(kbd_row+kbd_col)|KBD_VAL_VAILD;
							break;
						case 4:
							if(KR1)	key_val=(kbd_row+kbd_col)|KBD_VAL_VAILD;
							break;
						case 8:
							if(KR2)	key_val=(kbd_row+kbd_col)|KBD_VAL_VAILD;
							break;
						case 12:
							if(KR3)	key_val=(kbd_row+kbd_col)|KBD_VAL_VAILD;
							break;
						default:							
							break;
					}
					KR0=1;
					KR1=1;
					KR2=1;
					KR3=1;
					fsm_key=FSM_WAIT_RELESE;
					break;
				case FSM_WAIT_RELESE:
					if(!keypress){
						fsm_key=FSM_INIT;
					}
					break;
				default:
					fsm_key=FSM_INIT;
					break;
			}
		}
	}
}
void time2()interrupt 5 {//base 10 ms
	TF2=0;
	Timerout=1;
	scankey=KBD_PORT;
	if(scankey&0x0f){
		keypress=1;	
	}
	else{
		keypress=0;
	}

}