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RM51单片机实验板配套实验例程库

;---------------------------------------
;  四位共阳LED动态扫描显示程序
;  P0为段码口，P2为位选口（低电平有效）
;  参数为要显示的字符串指针
;---------------------------------------
                                     NAME     DISPLAY
?PR?_DISPLAY?DISPLAY SEGMENT  CODE
?CO?_DISPLAY?DISPLAY SEGMENT  DATA
                     EXTRN    CODE  (_DELAY)
                     PUBLIC   _DISPLAY
                     RSEG     ?CO?_DISPLAY?DISPLAY
?_DISPLAY?BYTE:      
       DISPBIT:      DS       1
       DISPNUM:      DS       1
                     RSEG     ?PR?_DISPLAY?DISPLAY
_DISPLAY:            PUSH     ACC
                     PUSH     DPH
                     PUSH     DPL
                     PUSH     PSW
                     INC       DISPNUM
                     MOV      A,      DISPNUM
                     CJNE      A,      #4D,  DISP1
DISP1:               JC         DISP2
                     MOV      DISPNUM,   #00H
                     MOV      DISPBIT,   #0FEH
DISP2:               MOV      A,      R1
                     ADD      A,      DISPNUM
                     MOV      R0,     A
                     MOV      A,      @R0
                     MOV      DPTR,   #DISPTABLE
                     MOVC     A,      @A+DPTR
                     MOV      P0,     A
                     MOV      A,      DISPNUM
                     CJNE     A,      #2D,  DISP3
                     CLR      P0.7
DISP3:		       MOV      P2,     DISPBIT
                     MOV      R6,     #00H
                     MOV      R7,     #0AH
                     LCALL    _DELAY
                     MOV      P0,     #0FFH
                     MOV      P2,     #0FFH
                     MOV      A,      DISPBIT
                     RL       A
                     MOV      DISPBIT,   A
                     POP      PSW
                     POP      DPL
                     POP      DPH
                     POP      ACC
                     RET
DISPTABLE:DB    0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H,88H,83H,0C6H,0A1H,86H,8EH,0BFH,0FFH
;                "0", "1", "2", "3","4", "5","6","7", "8","9","A","B","C", "D", "E","F", "-", " "
                     END