it is very hard to get exact required delay in embedded C programming
u hv to do trial and error for getting closest value of required delay
in loop inside loop it waste more cycles so we can not directly put 250*1000 = 250 ms
also we can not put 250*25*40 = 250 ms. instead we have to put different count like 40,39,38,36 …. likewise and check when there is closest value of 250 ms