说明：  FLASH转换层简易实现代码。用于FLASH底层驱动与上层应用之间，如文件以系统。实现了FLASH读写物理地址与虚拟地址的转换，损耗均衡，垃圾回收等功能。
(FLASH code conversion layer easy to achieve. FLASH underlying driver for the application and between the upper, such as file systems. To achieve a FLASH read physical address and virtual address translation, wear leveling, garbage collection and other functions.)