Using MPEG Layer-3 compression, 40 MByte audio files have been compressed to approximately 3.5 MBytes. With the wide availability of MP3 files via the Internet, portable MP3 players have become increasingly popular. MP3 players are currently available that utilize either Compact Discs, SmartMedia, Compact Flash, or a hard-drive as their storage medium.

Our interest in MP3 technology led us to design a circuit that would convert an MP3 file into an audio signal for our final project. The circuit utilizes an MP3 decoder chip to convert an MP3 file into a digital signal. The resulting digital signal is then converted to an analog audio signal via a Digital-to-Analog Converter (DAC). An 8-bit Microcontroller controls the flow of data to the MP3 decoder chip.

Since we finished the MP3 decoding circuit ahead of schedule, we decided to additionally implement a hard-drive interface to store the MP3 files. Once again, an 8-bit Microcontroller controlled all data transfers to and from the hard-drive. Due to time limitations, we were not able to finish the software drivers for this circuit.