dear sir/Madam i want to know some information about using voice in mcu ,i know need a D/A device for this reason, but i dont know how i use mp3 file in ROM,and how transfer this file to D/A you are very kindly to advise me
Actually there is an MP3 player device from Atmel (see AT89C51SND1 http://www.keil.com/dd/chip/3323.htm). There is an low-cost starter kit that contains already a framework. An alternative is to use the C167. On the TU Wien (Vienna) there was a Diploma work based on that. Take a look to http://www.ict.tuwien.ac.at/ (but the web side appears to be down in the moment). Also try Google and search for "MP3 C167".