rs232_2.asm

来自「用89S52进行DS1820温度读取程序」· 汇编 代码 · 共 88 行

        SW1        BIT   P2.7
        SW2        BIT   P2.6
        SW3        BIT   P2.5
        SW4        BIT   P2.4
        SW5        BIT   P2.3
        SW6        BIT   P2.2
        KEY        BIT   P3.3
         org 000h
         jmp start
         org 023h
         jmp rs_int
         ORG 100H
   start:MOV   SP ,#40H
         MOV   P1,0FFH      ;INIT
         MOV   P2,0FFH
         MOV   P0,0FFH
         MOV   P3,0FFH
         CLR   KEY
         mov   tmod,#20h
         mov   scon,#50h
         mov   TH1,#0FDH    ;sn=9600b/s-n-1
         MOV   TL1,#0FDH
         SETB   TR1
         SETB   ES
         SETB   EA
WAIT_KEY:JB    KEY,$       ;等候按键!
         JNB   SW1,SW1_OK
         JNB   SW2,SW2_OK
         JNB   SW3,SW3_OK
         JNB   SW4,SW4_OK
         JNB   SW5,SW5_OK
         JNB   SW6,SW6_OK
         JMP   WAIT_KEY
         SW1_OK:  MOV   SBUF,#11111110b
         JNB   TI,$
         CLR   TI
         LCALL  DELAY
         JNB   SW1,$
         JMP   WAIT_KEY
         SW2_OK:  MOV   SBUF,#11111101b
         JNB   TI,$
         CLR   TI
         LCALL  DELAY
         JNB   SW2,$
         JMP   WAIT_KEY
         SW3_OK:  MOV   SBUF,#11111011b
         JNB   TI,$
         CLR   TI
         LCALL  DELAY
         JNB   SW3,$
         JMP   WAIT_KEY
         SW4_OK:  MOV   SBUF,#11110111b
         JNB   TI,$
         CLR   TI
         LCALL  DELAY
         JNB   SW4,$
         JMP   WAIT_KEY
         SW5_OK:  MOV   SBUF,#11101111b
         JNB   TI,$
         CLR   TI
         LCALL  DELAY
         JNB   SW5,$
         JMP   WAIT_KEY
         SW6_OK:  MOV   SBUF,#11011111b
         JNB   TI,$
         CLR   TI
         LCALL  DELAY
         JNB   SW6,$
         JMP   WAIT_KEY
 RS_INT: PUSH  ACC
         PUSH  PSW
         JNB   RI,END_RS
         CLR   RI
         MOV   A,SBUF               ;读接收字节
         MOV   P1,A
END_RS: POP   PSW
        POP   ACC
        RETI
DELAY:  MOV  R7,#30
   D1:  MOV  R6,#20
   D2:  MOV  R5,#248
        DJNZ R5,$
        DJNZ R6,D2
        DJNZ R7,D1
        RET

        END