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
See the Atmel AT89C51SND1, mentioned above. It has the MP3 hardware (and more) and an 8051 controller integrated onto a single chip.
Using only a 8051 device, I strongly doubt you can ever decode MP3 data fast enough to play them. MP3 playback needs either hardware assistance by a special-purpose chip, or a rather high performance CPU. No 8051 I've heard of comes even close to being powerful enough for that.
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".
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