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Why do USB drives behave differently? 2g vs 4g — Parallax Forums

Why do USB drives behave differently? 2g vs 4g

T ChapT Chap Posts: 4,223
edited 2012-05-14 16:59 in General Discussion
I use a Vinculum and VS1033 to playback mp3 files. The system is a voice prompt for user programming. If the user pressed any key ahead of time or maybe exit, the code tells the file to stop. This is VMusic firmware. On a 2g Sandisk Cruzer the mp3 stops right away and the next file can start. On the same drive but a 4g, the file continues to play, and the next file then plays.

Comments

  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-05-13 18:17
    It could be a difference in the drivers between a standard and HC card, and possibly FAT16 and FAT32. You could test that by verifying the FAT in both cards. If the 4GB card is FAT32, try epartitioning it into two volumes, and using FAT16. See if that makes a difference. It could also be that the firmware is falling back to a slower speed because of (whatever) in the card. If FTDI publishes their code -- rather than just the precompiled version -- you could check how it handles different sizes and speeds of cards.

    Since these are MP3s, you can get a lot on a 1GB or 2GB card. Maybe always use a smaller card. You can still find them mail order, they are now very cheap.

    -- Gordon
  • tobdectobdec Posts: 267
    edited 2012-05-14 07:45
    Ive had similar issues with my 16g drives. On pc's and unix/linux systems all is well....if my gf or any of her mac loving friends try to put anything on them...all hell breaks loose. They can see the contents just not add delete or copy files.....As far as your issue goes I believe Gordon is right it sounds like a file system issue....and being from 2gb (none HC) to 4gb (HC) that may be an issue as well. When HC cards first came out the store I was working at had a few issues with older devices reading them correctly. Our solution ended up being to replace them cards with older ones in a few cases. Also find out what file systems the reader supports....maybe EXT4? sometimes a unix file system is supported..rarely but it does happen. GL!
  • PublisonPublison Posts: 12,366
    edited 2012-05-14 08:01
    I believe the OP is asking about thumb drives, since he is using them on a VMusic module.

    Jim
  • T ChapT Chap Posts: 4,223
    edited 2012-05-14 08:16
    OK you guys solved it. Every time I buy the 2gig Sandisk Cruzer, I just drag a a few hundred mp3's to it, and it just works. It is always FAT32. The same drive in a 4gig version was not acting right, I checked and it is also FAT32. I just formatted the drive on a PC, reinstalled the files and the issues went away. Not sure what the difference is, it is still FAT32. But in any case, your suggestions led me to reformat. Thanks!
  • tobdectobdec Posts: 267
    edited 2012-05-14 08:24
    Probably some typ of corruption...doesn't happen much on flash memory but can....in any case glad you got it solved!
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-05-14 08:59
    Publison wrote: »
    I believe the OP is asking about thumb drives, since he is using them on a VMusic module.

    These use firmware drivers within the FTDI Vinculum chip (the chip is upgradable and reprogrammable). The USB driver in these chips needs to communicate with the SD card, and it's here where differences in implementation between cards come into play.

    Needing to reformat cards isn't unusual, even when cards are fresh. They may have used weird cluster sizes on those 4G cards, for example.

    -- Gordon
  • tobdectobdec Posts: 267
    edited 2012-05-14 09:45
    Jesus Gordon.....your scope of knowledge blows me away!
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-05-14 12:08
    tobdec wrote: »
    Jesus Gordon.....your scope of knowledge blows me away!

    It's just Gordon. Jesus is that other guy. :smile:

    I'm just guessing here, BTW. Over the last three weeks I've had to work a lot of this out, so it's fresh in my mind with what can go wrong. The system I'm working with uses a comparable audio decoder chip (same company, but decodes Ogg Vorbis files), but supporting internal flash, external uSD, and USB. The program is so tightly packed into memory that with just one out of place sneeze it won't compile. I have a choice of also supporting WAV, but not HC cards, supporting seemless playback but not something else. It's very maddening.

    -- Gordon
  • tobdectobdec Posts: 267
    edited 2012-05-14 14:27
    What are you using to solder it? I assume its nano micro sized at least.....thats gota be tough!
  • PublisonPublison Posts: 12,366
    edited 2012-05-14 15:23
    @ T Chap

    Glad you got it working. For the record, you are using a thumb drive, correct?

    All the responses when off about SD cards. While the information from Gordon was very informative, (Thanks Gordon!), I would be good to have the correct hardware information used, for people querying this thread later.
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-05-14 16:05
    tobdec wrote: »
    What are you using to solder it? I assume its nano micro sized at least.....thats gota be tough!

    It's a surface mount board with everything already connected. Would be very difficult to hand-solder it all. This is for a project for an upcoming SERVO or Nuts & Volts.

    -- Gordon
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2012-05-14 16:28
    Publison wrote: »
    All the responses when off about SD cards.

    Sorry, I did use the term "card," out of habit I guess. Above where I say "SD card" it should say flash memory.

    -- Gordon
  • PublisonPublison Posts: 12,366
    edited 2012-05-14 16:50
    GordonMcComb wrote: »
    Sorry, I did use the term "card," out of habit I guess. Above where I say "SD card" it should say flash memory.

    -- Gordon

    No worries Gordon,

    Memory--it's all the same, we loose it when we get older. :)

    Jim
  • T ChapT Chap Posts: 4,223
    edited 2012-05-14 16:59
    Yes the Sandisk Cruzer I spoke about is a USB thumb drive.
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