how I can play ".wav" file using LPC2148 using internal 10 bit DACand how to play .wav files stored in SD card using SPI protocol
1. Study the LPC2148 Datasheet and other associated documents to find out how to use the DAC;
2. Research the .wav file format - there is plenty of documentation freely available;
3. Research accessing SD Card via SPI - again, there is plenty of documentation freely available.
4. Think about how to apply what you have learned to this task...