ORG 0000H
	JMP MAIN
MAIN: MOV DPTR,#0FF2BH
	MOV A,#00H
	MOV A,#90H;當是pc輸入pa輸出時為8bH
	MOVX @DPTR,A;將控制子放到控制寄存器中
LOOP:	MOV DPTR,#0FF28H
	MOVX A,@DPTR
	MOV DPTR,#0FF2AH
	MOVX @DPTR,A
	JMP LOOP
END