Building a Portable MP3 Player

Figure 1 

The goal of this project is to create their own version of MP3 using inexpensive materials and at the same time it is useful and has a potential to be popular as alternative to those who are available in the market that is quite pricey.

They used the ATMEL AT90S8535 microcontroller to control the components and data flow. It has MMC that uses an SPI interface to control the card and transfer data. They also put pushbuttons to be used to control the operation of the player as the four functions are play, stop, next track, and previous track. To be able to send a command to the card, the user must lower SS, put data on the MOSI line, and toggle SCLK Programming the MMC was done through a PCs parallel port. They also wrote a programmer in C++ which initializes the MMC and the programmer is a DOS executable.

The programmer also builds and writes a table of contents for the MMC, and they remove the ATMEL chip from the development board and use four AA cell batteries to draw power for the MCU, the decoder, and the MMC.

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