RS EQU P2.5
RW EQU P2.6
E EQU P2.7
ORG 0000H
LJMP MAIN
ORG 0030H
INIT:
LCALL DELAY
LCALL BUSY
MOV R0,#01H
LCALL WFT
MOV R0,#38H
LCALL WFT
MOV R0,#0CH
LCALL WFT
MOV R0,#06H
LCALL WFT
RET
MAIN:
LCALL DELAY
LCALL INIT
MOV R0,#'A'
LCALL WNB
SJMP $
BUSY:
PUSH ACC
MOV P3,#0FFH
CLR RS
SETB RW
BUSY0:
SETB E
NOP
MOV A,P3
CLR E
JB ACC.7,BUSY0
POP ACC
RET
WFT:
LCALL BUSY
CLR RS
CLR RW
SETB E
MOV P3,R0
NOP
CLR E
RET
WNB:
LCALL BUSY
SETB RS
CLR RW
SETB E
MOV P3,R0
NOP
CLR E
RET
DELAY:
MOV R4,#05H
D1:MOV R5,#0FFH
DJNZ R5,$
DJNZ R4,D1
RET
END

字模会默认从第一行第一个开始显示