Problem in rtc ds12887A display

[syedshah]

Hi,
i am building up a clock using ds 12887a interfaced with microcontroller at89c51 taking display on 7segments.I have taken output of seconds,minutes and hours seprately and it is indeed working fine.But when i try to take display of minutes and seconds collectively,minutes are shown only for 2 seconds than seconds start ro dispay on segments dedicated for minutes.This action continues for 2 seconds than minutes are displayed again for 2 seconds and the cycle continues.Here is the code i have written for achieving the task.Please help me out anyone!!


ORG 000H
SJMP MAIN
MAIN:
;--------TURNING ON
MOV R0,#10
MOV A,#20H
MOVX @R0,A
;--------SETTING TIME MOD
MOV R0,#11
MOV A,#83H
MOVX @R0,A
;--------SETTING TIME
MOV R0,#0
MOV A,#55
MOVX @R0,A ; FOR SEC
MOV R0,#02
MOV A,#12
MOVX @R0,A ;FOR MIN
MOV R0,#04
MOV A,#04
MOVX @R0,A ;FOR HR
;--------TIME UPDATE
MOV R0,#11
MOV A,#04
MOVX @R0,A
;--------READ TIME

AGAIN:
MOV R0,#0 ;ADDRESS FOR SECONDS
MOVX A,@R0
MOV R1,A
MOV R0,#2 ;ADDRESS FOR MINUTES
MOVX A,@R0
MOV R2,A
ACALL DIVIDE
ACALL DIS1
ACALL DIS2

SJMP AGAIN ;REPEAT CYCLE



DIVIDE: ;CONVERSION TO BCD FOR DISPLAY ON 7 SEGMENTS

CLR A
CLR B
MOV A,R1
MOV B,#10
DIV AB
MOV R3,A
MOV R4,B
CLR A
CLR B
MOV A,R2
MOV B,#10
DIV AB
MOV R5,A
MOV R6,B
RET


DIS1: ;DISPLAY FOR SECONDS
CLR P3.2
CLR P3.3
CLR P3.1
SETB P3.0
MOV P2,R3
ACALL DELAY
CLR P3.0
SETB P3.1
MOV P2,R4
ACALL DELAY
CLR P3.1
RET

DIS2: ;DISPLAY FOR MINUTES
CLR P3.0
CLR P3.1
CLR P3.3
SETB P3.2
MOV P2,R5
ACALL DELAY
CLR P3.2
SETB P3.3
MOV P2,R6
ACALL DELAY
CLR P3.3
RET

DELAY:
MOV TMOD,#01
MOV TL0,#0AH
MOV TH0,#0FFH
SETB TR0
JNB TF0,$
CLR TR0
CLR TF0
RET