60s.asm

可实现0到99秒的计时。程序简单易读

ORG 0000H
LJMP MAIN
ORG 000BH
SJMP T0Z
ORG 0030H
MAIN:
MOV DPTR,#SEG7
MOV R2,#60
MOV R4,#20
SETB EA
SETB ET0
MOV TMOD,#01H
MOV TH0,#3CH
MOV TL0,#0B0H
SETB TR0
DISP:
MOV A,R2
MOV B,#10
DIV AB
MOVC A,@A+DPTR
MOV P2,A
SETB P3.0
LCALL DELAY
CLR P3.0
MOV A,B
MOVC A,@A+DPTR
MOV P2,A
SETB P3.1
LCALL DELAY
CLR P3.1
SJMP DISP
T0Z:
MOV TH0,#3CH
MOV TL0,#0B0H
DJNZ R4,T0Z0
MOV R4,#20
DJNZ R2,T0Z1
CLR TR0
SJMP T0Z1
T0Z0:RETI
T0Z1:
MOV A,R2
MOV B,#10
DIV AB
MOVC A,@A+DPTR
MOV P2,A
SETB P3.0
LCALL DELAY
CLR P3.0
MOV A,B
MOVC A,@A+DPTR
MOV P2,A
SETB P3.1
LCALL DELAY
CLR P3.1
RETI
SEG7:DB 0C0H,0F9H,0A4H,0B0H
    DB 99H,92H,82H,0F8H
    DB 80H,90H,88H,83H
    DB 0C6H,0A1H,86H,8EH
DELAY:
MOV R7,#20
D1:MOV R6,#200
DJNZ R6,$
DJNZ R7,D1
RET
END