Re: [Libusb-devel] Using libusb with a USB SD Card reader.

[Douglas E. E. <dee...@an...>]

On 10/24/2011 2:11 PM, Tim Roberts wrote:
> Eric Sepich wrote:
>> Actually what I have been using is a program called F3 by Michelle
>> Machado.
>
> I don't know what that is, and Google was not helpful.
>
>> The program works very well but I am having a very specific issue with
>> thousands of SD cards that my client bought. Essentially I can not get
>> any SD card readers to read the cards at all. I know it is a long shot
>> but I was going to try to write some code at the hardware level to try
>> to "wake the cards up" so to speak and make an attempt at formatting them.
>
> Are you aware there are several different kinds of SD cards?  An SD card
> reader cannot access SDHC or SDXC cards, and no amount of software or
> driver effort can every make it happen.  The hardware is simply not
> compatible.
>
> It would be much more productive for you to get some electrical
> engineering help to figure out where the problem lies.  Right now, what
> you are proposing is nothing more than a shot in the dark.  There is
> nothing you can achieve at a low level that the existing drivers are not
> already doing.
>
>> I don't think any of you really understand that with tens of thousands
>> of dollars on the line that it is indeed worth it to make an effort.
>
> Of course we do.  We all live in the business world in our real lives.
> However, time costs money, too.  Starting from scratch, you are a couple
> of months away from achieving your goal.  How much is your time worth?
> Who is paying for that?  Is it your client?  It's quite possible that
> the most economic solution is to sell those SD cards on eBay and go buy
> another bunch that are known to work.
>
>> Your warnings about how much there is to learn I do heed however being
>> a self educated systems administrator as well as a self educated
>> programmer in too many languages to list I felt up to the task.
>> Mastering systems is something of a lifelong quest for me. In any
>> event I am the first to admit that I do have much to learn. Thanks for
>> the help out but perhaps I should get a book on programming the USB
>> port and start cracking away at that.
>
> USB is the easy part.  The USB Mass Storage Class specification uses the
> SCSI command set to communicate with the drive on a low level, so you'll
> have to understand SCSI.  The MSC specification can be downloaded from
> the USB web site at www.usb.org.  Then, you'll have to understand
> partitions and file systems.

There are hobbyist out there trying to use SD cards. Check this out:
http://forums.parallax.com/showthread.php?95774-Poor-Man-s-SD-Card-Socket&p=661502#post661502

This might also help you identify what you have:
https://www.sdcard.org/home/

And to format a card:
https://www.sdcard.org/downloads/formatter_3/

(I have not tried any of these of these.)
>

-- 

  Douglas E. Engert  <DEE...@an...>
  Argonne National Laboratory
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