注释程序L8255_CMD EQU 273HL8255_PA EQU 270HL8255_PB EQU 271HL8255_PC EQU 272H SSEG SEGMENT STACK DW 20 DUP (?)SSEG ENDS CSEG SEGMENT ASSUME CS:CSEG,SS:SSEGBEGIN: MOV CX,0FFHAA: LOOP AA； MOV DX,L8255_CMD MOV AL,98H ;10011000 OUT DX,AL NOP NOP NOP NOP NOP BB: MOV DX,L8255_PA IN AL,DX;读取PA口,硬件接开关量输出模块0-7 XOR AL,0FFH;AL异或 0FFH, 异则为1 MOV DX,L8255_PB; OUT DX,AL; ALàPB口DS19—DS12，共阳极， AL位为0的亮 JMP BBCSEG ENDS END BEGIN