依据SD2.0规范编写的能读写SDHC的驱动程序(包含SDHC卡的支持，支持4G以上的SD卡)，使用 mega128 单片机，实现mp3功能。-SD2.0 specification prepared in accordance with read and write SDHC driver (including support for SDHC cards to support more than 4G of the SD card), the use of single-chip mega1