基于at89c52的简易时钟（汇编）

程序代码：
    ORG 0000H
    LJMP START
    ORG 000BH
    LJMP timer0Interrupt
START:
    MOV SP,#30H
  MOV DPTR,#TABLE
    LCALL InitTimer0
  MOV R0,#23
  MOV R1,#59
  MOV R2,#50
  MOV R3,#0
JISHI:
CJNE R2,#60,LOOP1
MOV R2,#0
INC R1
CJNE R1,#60,LOOP1
MOV R1,#0
CPL P2.1
LCALL DELAY500MS
CPL P2.1
INC R0
CJNE R0,#24,LOOP1
MOV R0,#0
LOOP1:
LOOP:
LCALL XIANSHI
JNB P1.0,JIAOSHI ;设置功能键第一次按下，跳转到校时
JMP JISHI
JIAOSHI:
CLR EA ;关闭中断
FEN:
JNB P1.1,JIAF
CALL XIANSHI
CALL DELAY1MS
JNB P1.2,JIANF
CALL XIANSHI
CALL DELAY1MS
JNB P1.0,SHI ;设置功能键再次按下，跳转到时调整
JNB P1.3,JISHI ;检测确认功能键是否按下
JMP FEN
SHI:
JNB P1.1,JIAS
CALL XIANSHI
CALL DELAY1MS
JNB P1.2,JIANS
CALL XIANSHI
CALL DELAY1MS
JNB P1.0,FEN ;设置功能键再次按下，跳转到分调整
JNB P1.3,JISHI ;检测确认功能键是否按下
JMP SHI
JIAF:
INC R1
JMP FEN
JIANF:
DEC R1
JMP FEN
JIAS:
INC R0
JMP SHI
JIANS:
DEC R0
JMP SHI

XIANSHI:
MOV A,R0
MOV B,#10
DIV AB
MOVC A,@A+DPTR
MOV P0,A
MOV P3,#00000001B
CALL DELAY1MS
MOV A,B
MOVC A,@A+DPTR
MOV P0,A
MOV P3,#00000010B
CALL DELAY1MS
MOV A,R1
MOV B,#10
DIV AB
MOVC A,@A+DPTR
MOV P0,A
MOV P3,#00000100B
CALL DELAY1MS
MOV A,B
MOVC A,@A+DPTR
MOV P0,A
MOV P3,#00001000B
CALL DELAY1MS
RET
InitTimer0:   ;定时器初始化，
    MOV TMOD,#01H ;模式1
    MOV TH0,#0D8H ;定时器高8位赋值
    MOV TL0,#0F0H ;定时器低8为赋值
    SETB EA ;打开中断
    SETB ET0 ;打开计时器0中断
    SETB TR0 ;启动定时器0
    RET
DELAY1MS:   ;误差 0us
    MOV R7,#01H
DL1:
    MOV R6,#8EH
DL0:
    MOV R5,#02H
    DJNZ R5,$
    DJNZ R6,DL0
    DJNZ R7,DL1
    RET
DELAY500MS:   ;误差 0us
    MOV R7,#17H
DL3:
    MOV R6,#98H
DL2:
    MOV R5,#46H
    DJNZ R5,$
    DJNZ R6,DL2
    DJNZ R7,DL3
    RET
Timer0Interrupt:
    PUSH DPH
    PUSH DPL
    PUSH ACC
    MOV TH0,#0D8H
    MOV TL0,#0F0H
    INC R3   
    POP ACC
    POP DPL
    POP DPH
  CJNE R3,#90,EXIT
  INC R2
  CPL P2.0
  MOV R3,#0
EXIT:
    RETI
TABLE: ;共阴极数码管段码
DB 00111111B ;0
DB 00000110B ;1
DB 01011011B ;2
DB 01001111B ;3
DB 01100110B ;4
DB 01101101B ;5
DB 01111101B ;6
DB 00000111B ;7
DB 01111111B ;8
DB 01101111B ;9
END