LSVคลังสมองออนไลน์ "ปีที่21"

;//***** READ KEY PAD *****//;
;//* INPUT	: -
;//* OUTPUT	: ACC,KEY_FLAG
;//* REG. USE	: A,B,COUNTER,DLY0,DLY1
READ_KEY:	MOV	B,#11110111B			;--->>> SCAN ROW 1
		MOV	COUNTER,#0			;--->>> RESET COUNTER

READ_COL:	MOV	KEYPORT,B
READ_COL1:	JB	COL1,READ_COL2			;--->>> READ COLUMN 1
		ACALL	DEBOUNCE
		JB	COL1,READ_COL2
		AJMP	FIND_SW0
		
READ_COL2:	JB	COL2,READ_COL3			;--->>> READ COLUMN 2
		ACALL	DEBOUNCE
		JB	COL2,READ_COL3
		AJMP	FIND_SW1
		
READ_COL3:	JB	COL3,READ_COLE			;--->>> READ COLUMN 3
		ACALL	DEBOUNCE
		JB	COL3,READ_COLE
		AJMP	FIND_SW2

READ_COLE:	MOV	A,B				;--->>> SCAN NEXT ROW
		RL	A				;--->>>
		MOV	B,A				;--->>>
		
		MOV	A,COUNTER			;--->>> COUNTER = COUNTER + 3
		ADD	A,#3				;--->>>
		MOV	COUNTER,A			;--->>>
		
		CJNE	A,#12,READ_COL			;--->>> A = 12 ?
		CLR	KEY_FLAG
		RET

FIND_SW2:	INC	COUNTER				;--->>> COUNTER = COUNTER + 1
FIND_SW1:	INC	COUNTER				;--->>> COUNTER = COUNTER + 1
FIND_SW0:	MOV	A,COUNTER
		MOV	DPTR,#KEY_TABLE
		MOVC	A,@A+DPTR
		SETB	KEY_FLAG
		RET
		
RELEASE_SW?:	MOV	A,KEYPORT			;--->>> CHECK KEY RELEASE
		ORL	A,#11111000B			;--->>> DATA = 11111000 + P1
		CPL	A				;--->>> COMPLEMENT
		JNZ	RELEASE_SW?			;--->>> JUMP IF ACC NOT ZERO
		RET

DEBOUNCE:	MOV	DLY0,#50
DEBOUNCE1:	MOV	DLY1,#230
DEBOUNCE2:	NOP
		NOP
		DJNZ	DLY1,DEBOUNCE2
		DJNZ	DLY0,DEBOUNCE1
		RET

;//***** TABLE OF CONT. *****//;
KEY_TABLE:	DB	1,2,3,4,5,6,7,8,9,"*",0,"#"