这个工程主要是简单的显示SD卡的文件目录。
This project implements a simple file explorer that displays the directory structure on the SD card.The included CircleOs binary include a SDIO driver and a Fat12/16/32 implementation based on DosFS. This a demo project to show usage of the SD card.
This project is aimed to be a demo project about how to use the CircleOS filesystem. It can display PRM (converted BMP, JPG, etc) images with a sample viewer.
Included in this project an application to convert BMP, JPG, etc files to PRM with the functionality to scale the image to a desired resolution.
 Current layout of PRM image file:
 8byte header:
- byte 0: height
- byte 1: width
- 6 bytes for future use
& J/ t7 Z4 P9 B0 I- pixel data (2 bytes per pixel)
- W# o0 v" ~9 B, f1 M FS interface functions:
u32 FS_Mount(enum STORAGE_device device);
) P, L' M" H, ?" |  |u32 FS_Unmount(enum STORAGE_device device);
" O5 r7 \! V8 ~" d2 f  uu32 FS_OpenFile(PVOLINFO volinfo, u8 *path, u8 mode, PFILEINFO fileinfo);
u32 FS_ReadFile(PFILEINFO fileinfo,  u8 *buffer, u32 *successcount, u32 len);
u32 FS_WriteFile(PFILEINFO fileinfo,  u8 *buffer, u32 *successcount, u32 len);
u32 FS_Close(PFILEINFO fileinfo);
void FS_Seek(PFILEINFO fileinfo, u32 offset);
. E. M" {& p9 K/ Su32 FS_Delete(PVOLINFO volinfo, u8 *path);
6 D- t3 N9 p: S  k2 J8 i6 L* gu32 FS_GetNextEntry(PVOLINFO volinfo, PDIRINFO dirinfo, PDIRENT dirent);
, o- V# C3 y" r2 R' tu32 FS_OpenDirectory(PVOLINFO volinfo,u8 *dirname, PDIRINFO dirinfo);
3 C% D+ ~9 E( h" ^7 J. ]- N, Xu32 FS_GetVolumeInfo(u8 unit,  u32 startsector, PVOLINFO volinfo);
 
* f2 y% Z+ i/ n 
This is a snapshot of my current work in progress with partially integrated jpg decompressor