后板第一次提交

lvgl_v8_back/lvgl/docs/libs/fsdrv.md

@@ -0,0 +1,21 @@
+
+# File System Interfaces
+
+LVGL has a [File system](https://docs.lvgl.io/master/overview/file-system.html) module to provide an abstraction layer for various file system drivers.
+
+LVG has built in support for:
+- [FATFS](http://elm-chan.org/fsw/ff/00index_e.html)
+- STDIO (Linux and Windows using C standard function .e.g fopen, fread)
+- POSIX (Linux and Windows using POSIX function .e.g open, read)
+- WIN32 (Windows using Win32 API function .e.g CreateFileA, ReadFile)
+
+You still need to provide the drivers and libraries, this extension provides only the bridge between FATFS, STDIO, POSIX, WIN32 and LVGL.
+
+## Usage
+
+In `lv_conf.h` enable `LV_USE_FS_...` and assign an upper cased letter to `LV_FS_..._LETTER` (e.g. `'S'`).
+After that you can access files using that driver letter. E.g. `"S:path/to/file.txt"`.
+
+The work directory can be set with `LV_FS_..._PATH`. E.g. `"/home/joe/projects/"` The actual file/directory paths will be appended to it.
+
+Cached reading is also supported if `LV_FS_..._CACHE_SIZE` is set to not `0` value. `lv_fs_read` caches this size of data to lower the number of actual reads from the storage.