MP3制作资料很全，里面有PCB，原理图还有详细的源码。-MP3 production of information is very wide, containing PCB, there is a detailed schematic source.

用AVR单片机开发的mp3，的所有资料，包括程序原理图和PCB图-With AVR microcontroller development of mp3, all information, including procedures for schematic and PCB diagram