This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

file size in usb host

Hello Sir,

I am working on usb host using LPC2468 and i am using usb hostlite source code .I converted this source code compatible for FAT32 system.I am facing a problem when I create a file with extension RTF or DOC and try to write data less than 100kb and open this file on PC every thing is ok but when I write data greater than 100kb and try to open this file on PC there is a message on PC.

An unexpected error occurred while reading filename.

In USB hostlite WRITE_SIZE is given 10 * 1000000

what,s the reason for that?

Thanks & Regards
Rohit

  • I'm not sure, what is the direct cause of your troulbe.
    Get more clues on your problem.

    > An unexpected error occurred while reading filename

    This error message suggests directory on the media is broken.
    Confirm it by reading out the directory sector from the media, using a disk utility on PC.

    Disk Probe
    - Included in Windows install CD/DVD, in \Support\Tools folder
    or
    - Windows XP Service Pack 2 Support Tools
    " href= "http://www.theabsolute.net/sware/dskinv.html">www.theabsolute.net/.../dskinv.html

    The structures of directory and its entries are described in
    MS FAT32 System spec
    msdn.microsoft.com/.../gg463080.aspx

    There are easier explanations on the web, for example,
    www.easeus.com/.../root-directory-management-in-FAT32.htm

    Interpret the sector read out, and specify broken field of directory entry.

    These functions touch to directory entry.

    usbhost_fat.c
    - FAT_CreateEntry() - make new entry
    - FAT_PutSFN() - Filename
    - FAT_UpdateEntry() - File length
    - FILE_Close() - File length

    Now that on debugger, you'll trace why one of these function puts wrong value to the directory entry.

    Tsuneo

  • Thanks Sir for your kind support

    Sir, I notice that when i use 100 in place of MAX_BUFFER_SIZE which is 4000 in usbhostlite source code problem occur.
    but if i use MAX_BUFFER_SIZE equal to 4000 then there is no problem.

    One thing more i want to confirm why WRITE_SIZE is (10 * 1000000)
    is there is any special reason for that?

    Thanks & Regards
    Rohit