Usb mass storage
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USB Mass Storage. USB Mass Storage Architecture C Library to FAT File System Interface FAT File System USB Mass Storage Driver Recommended Readings. USB Mass Storage Architecture. C Library to File System Interface.

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USB Mass Storage

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Usb mass storage

USB Mass Storage

  • USB Mass Storage Architecture

  • C Library to FAT File System Interface

  • FAT File System

  • USB Mass Storage Driver

  • Recommended Readings


Usb mass storage architecture

USB Mass Storage Architecture


C library to file system interface

C Library to File System Interface

  • Interfaces the supported C library file I/O functions to the FAT file system and native file system.

  • Supported C library file I/O functions are: mkdir, rename, remove, fopen, fclose, fread, fwrite, fseek.

  • All FAT volumes are referenced with a single letter.


C library to file system interface cont

C Library to File System Interface – cont.

  • All native file system volumes are referenced with anything other than a single letter.

  • If FAT volume is drive A, do fopen(“A/dir1/dir2/filename”, “w+”)

  • If native FS RAM volume is drive RAM0, do fopen(“RAM0/dir1/dir2/filename”, “w+)


Fat file system

FAT File System

  • Sourced from HCC-Embedded in Hungary.

  • Supports FAT12/16/32 depending on size of the media.

  • Supports long file names, multiple FAT volumes, multiple open files per volume and is thread safe.

  • Features a API similar to the C library file I/O functions, but with more functionality.


Fat file system cont

FAT File System – cont.

  • The FAT file system is limited to 8.3 file names, 1 FAT volume and 1 open file per volume and is thread safe.

  • FAT file system is version 2.62. Current versions have additional features such as thread context for current working directory (cwd) and a semaphore to synchronize access to each FAT volume.


Usb mass storage driver

USB Mass Storage Driver

  • Tested with USB 2.0 and 1.1 full speed Flash memory sticks.

  • Creates FAT volume on device insertion and removes FAT volume on device removal (just like Windows).

  • Uses the lowest drive letter to reference the newly created FAT volume.


Usb mass storage driver cont

USB Mass Storage Driver – cont.

  • Supports up to 4 devices

  • Driver initialization function usb_ms_init() allows specifying event notification or polling to notify user that a device was inserted and a FAT volume was created.


Recommended readings

Recommended Readings

  • HCC-Embedded FAT12/16/32 manual in /netos/src/examples/nafatfs


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