Re: [iPAQ] SD Card protocol specs

On Thursday 27 February 2003 04:12 am, Philip Blundell wrote:
> On Thu, 2003-02-27 at 09:01, Marc Baaden wrote:
> > Just a thought, would it be possible and permitted for someone not having
> > signed the NDA to reverse-engineer the binary Zaurus driver and write an
> > open-source one based on the reverse-engineering ?
>
> Depends on the jurisdiction where the work was carried out. In the US,
> I think this would almost certainly be prohibited by law. It might be
> OK in Europe, though I think the SD Consortium would probably try to
> make life miserable for anybody who did this.
>
> p.

Why not just write a driver to support the MMC protocol? You can download
that from www.sandisk.com and other places. MMC cards and SD cards are
essentially the same form factor. There's no real performance advantage of
SD over MMC typically because getting an SD card into 4 bit data mode is
apparently a carefully guarded secret at every SD card manufacturer, and the
maximum data rate in 1 bit mode is the same for either type of device
(20MB/s). Once you get a working MMC driver, it's a relatively simple (but
currently under NDA) step to get SD cards working, albiet without any of the
security features or 4 bit data xfers. That would be fairly easy to reverse
engineer...

-- 
  Jeff Sutherland, Accelent Systems, Inc.   <http://www.accelent.com>
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