physical sd-card emulator

Tue Jun 14, 2011 8:44 pm   

Haven't had much luck searching for this; the terms are too commonly
used in things other than what I'm looking for.

Has anyone tried to emulate an SD-card, as in, some hardware you plug
into an sd-card socket that acts like a physical sd-card, but is backed
by some other storage (hard drive, ram, another computer, etc)?

Back in the day, EEPROM emulators that were RAM-backed were popular,
this would be a modern equivalent.

And no, it's not critical, mostly just a curiosity as I try to squeeze
the most performance out of an embedded board.

Wed Jun 15, 2011 8:35 am   

On a sunny day (Tue, 14 Jun 2011 16:44:10 -0400) it happened DJ Delorie
<dj_at_delorie.com> wrote in <xn7h8oi1np.fsf_at_delorie.com>:


I have looked into this, the SDcard specs are free on the web,
but those have some horrible modes, iI am not sure it is guaranteed the card
reader will work with just the simplest protocol,
so I decided it was not worth the many many hours of writing a full
compatible software...

I did write a SDcard 'reading' module (or rather modifed some code I found).
So for the simplest protocol that should not be that hard to reverse.
And then you will likely have to 'simulate' some MS filesystem too.
Well that code I did write once, all on my website somewhere.
There is also a difference in sector size for SDcards > 2 GB (IIRC),
so what do you want it for? Emulation an 'old' < 2GB card?
Just buy a new gadget

Wed Jun 15, 2011 5:13 pm   

Jan Panteltje <pNaonStpealmtje_at_yahoo.com> writes:

I have a gadget that works with any SDcard. But SDcards are not the
fastest thing around (esp writing, even for the fastest available
cards), so I started wondering how to make a faster SDcard for it,
through hardware emulation...


I'm running Linux on the gadget, so this is not an issue for me. It
already knows all that stuff.

Sat Jun 18, 2011 5:49 am   

On Wed, 15 Jun 2011 13:13:30 -0400, DJ Delorie <dj_at_delorie.com> wrote:


If you really want the speed, you can try battery backed static ram. Or
even fast dynamic ram with a much bigger battery. In either case the SD
card interface becomes the limiting factor.

Tue Jan 31, 2012 8:52 pm   

Did you ever find a solution? I'd like a device like this to do automated testing.