说明：  便携式MP3播放器，基于AVR atmega ，winavr编程。
(About 10 years ago, I built a Portable MP3 Player first and I have done a number of MP3 related projects for hobby and business until now. However because I do not listen music out of door, that portable player have been used as only car audio player and I had not built portable one. The first portable player uses a SmartMedia (SM) as data recording media because the available memory card at that time was only SM and CF. The SM was closed soon and replaced by SD memery card (SDC). Therefore the data storage media of the player has been outdated and I decided to build a new one. The main application is car audio player so that the design should be specified for such use. But I tried to build it again as a small portable player by my preference.)