microcontroller ROM
sanjan,
first, state, which microcontroller family are you talking about - 8051, PIC, AVR, HC08 etc. There are not so many, but they are really distinct from each other.
Second, please, use proper english, including the vowels. Abbreviations such as "r" instead of "are", "wht" instead of "what" are really hard to understand. This environment is not SMS, you don't need to spare letters. In such a forum you are basically asking for a favour of a free help from other participands, and if the readers can't understand your question, they won't answer.
JW