MP3 Player - Components Explained...

The main component of the board is the MP3 decoder, the chipset MAS3507 from Micronas.
This chip receives mp3 stream and convert it to an uncompressed signal.

For more informations, look at Micronas datasheet (399k).

The second component of the board is the DAC converter, the chipset DAC3550 from Micronas too.
This chip receives numeric audio stream and convert it to analogic audible sound.
The chip provides 2 outputs. One of them is amplified for connect a headphone, and other one isn't amplified for connect to any amplifier.

For more informations, look at Micronas datasheet (391k).

This is the heart of the board.

• The microprocessor 16f877 from Microship stores the program used for read Hard-Drive, CD-Rom, send signal to MAS, display informations to LCD...
  You can upgrade the firmware directly from parallel port when a new version is released.
• EEPROM part is used to remember volume, bass and treble values when power is cycled.
  Firmware remembers both CD and HD settings separately.

For more informations, look at Microshop datasheet (2048k).

• The SRam buffer is used when playing MP3 files to maintain a constant flow of data to the Decoder.
  MP3 stream is stored from HD to SRam before playing it.
• MP3 File Structure is stored in the SRam too

For more informations, look at Cypress datasheets (230k).

74ACT04 : Hex Inverter.
74ACT138 : 1-of-8 Decoder/Demultiplexer.
74ACT245 : Octal Bidirectional Transceiver with TRI-STATE… Inputs/Outputs.
74ACT573 : Octal Latch with TRI-STATE Outputs.

For more informations, look at the datasheets (787k).
This document (14k) explains differences between models (AC, ACT, HCT...).

The LCD panel will display song titles.
You need to use any Hitachi HD44780 based LCD panel...

For more informations, look at Hitachi datasheet (318k).