单片机与单片机的串行通信

ORG 0000H
LJMP MAIN
ORG 0023H
LJMP INT_ES
ORG 0100H
MAIN:  MOV SP,#70H
        LCALL BEG  ;调用7279初始化  
MOV 61H,#00H ;计按键次数  
MOV 40H,#0FFH ;显示缓冲区 
MOV 41H,#0FFH
MOV 42H,#0FFH
MOV 43H,#0FFH
MOV 44H,#0FFH
MOV 45H,#0FFH
MOV 46H,#0FFH
MOV 47H,#0FFH 
MOV TMOD,#20H           ;串口初始化   
        MOV TH1,#0F4H
        MOV TL1,#0F4H
        MOV PCON,#00H
        MOV SCON,#50H
        MOV IE,#90H
        SETB TR1
MOV R0,#40H
    MOV R1,#40H
CLR RI
CLR TI
CLR 02H
CLR 03H
ST:    LCALL DIR ;调用显示 

   MOV C,02H ;判断接收允许
JNC ST1
LCALL DIR ;调用显示 
CLR 02H
     LJMP ST  
ST1:  LCALL KEY ;读键盘
CJNE A,#0FFH,M1 ;
LJMP ST
M1:     LCALL KEYY ;调用键盘处理子程序   
MOV C,03H
JC M2
LCALL XS ;调用显缓处理子程序  
SJMP M3
M2:   LCALL AD
LCALL DIR
M3:     CLR 03H
LJMP ST
BEG:   CLR P1.0             ;7279初始化  
       MOV R6,#0CH
GO:    DJNZ R6,GO
       MOV A,#0A4H
       ACALL STFS
       MOV R6,#02H
G1:    DJNZ R6,G1
       SETB P1.0
       RET
STFS:  MOV R7,#08H            ;发送一个字节  
B0:    RLC A
       MOV P1.2,C
       SETB P1.1