i have already givem one sample code earlier.
and also the following simple code too not working
while i change the delay count it gives only constant same value

C:0x0000 850189 MOV TMOD(0x89),0x01
HERE:
C:0x0003 85F28A MOV TL0(0x8A),0xF2
C:0x0006 85FF8C MOV TH0(0x8C),0xFF
C:0x0009 B295 CPL 0x90.5
C:0x000B 110F ACALL DELAY(C:000F)
C:0x000D 80F4 SJMP HERE(C:0003)
DELAY:
C:0x000F D28C SETB TR0(0x88.4)
AGAIN:
C:0x0011 308DFD JNB TF0(0x88.5),AGAIN(C:0011)
C:0x0014 C28C CLR TR0(0x88.4)
C:0x0016 C28D CLR TF0(0x88.5)
C:0x0018 22 RET