COUNT1 EQU 209H COUNT2 EQU 20AH Z8255 EQU 203H D8255A EQU 200H D8255B EQU 201H D8255C EQU 202H DATA SEGMENT SEC DB 1 DUP(?) SIGN1 DB 1 DUP(?) DATA ENDS

CODE SEGMENT ASSUME CS:CODE START:

;8255初始化

MOV DX,Z8255 ;控制端口8255 MOV AL,10000010B ;B口输入，A口输出 OUT DX,AL

MOV DX,D8255A

MOV AL,0FFH ;清零 OUT DX,AL ;8253初始化

MOV AL, 00110101B ; 计数器0,先读/写低字节，后高字节,方式2,BCD

MOV DX, Z8253 OUT DX, AL

MOV Al, 00H MOV DX, COUNT0

OUT DX, AL ; 计数器低字节 MOV AL, 50H

OUT DX, AL ; 计数器高字节

MOV AL, 01110111B ; 计数器1,先读/写低字节，后高字节,方式3,BCD

MOV DX, Z8253 OUT DX, AL MOV AL, 00H

MOV DX, COUNT1

OUT DX, AL ; 计数器低字节 MOV AL, 04H OUT DX, AL MOV DX,Z8279

MOV AL,00H ;设置8279的工作方式,8个字符显示，右入口 OUT DX,AL