because this value give almost 1ms delay ..
let if we use 11.0592MHz crystal ..
u know 8051 takes 12 pulses for 1 machine cycle
then period of one machine cycle would be
11.0592MHz/12 = 921.6KHz
t = 1/f
so time period of one machine cycle = 1/ 921.6KHz = 1.085us
now when u run loop of 1275..
delay would be 1275×1.085us = 1.3ms
practically this value gives delay of almost 1ms…
correct me ……..