- SDHC questions
- Posted by analox on February 18th, 2008
Hi there,
I need the SDHC spec cause I got to adapt existing embedded code to
support the HC cards.
neither google nor Sandisk helped. Any ideas where to get the spec
from would be highly appreciated.
Do ordinary built in SD card reads in laptops support SDHC?
Is there anything out for cards beyond 32 GB ?
tia
w.b.
- Posted by Stephen Pelc on February 18th, 2008
On Mon, 18 Feb 2008 01:19:26 -0800 (PST), analox <analox@gmx.de>
wrote:
Google for
SD Host Controller Standard Simplified Specification
Stephen
--
Stephen Pelc, stephenXXX@mpeforth.com
MicroProcessor Engineering Ltd - More Real, Less Time
133 Hill Lane, Southampton SO15 5AF, England
tel: +44 (0)23 8063 1441, fax: +44 (0)23 8033 9691
web: http://www.mpeforth.com - free VFX Forth downloads
- Posted by Peter Dickerson on February 19th, 2008
"Stephen Pelc" <stephenXXX@mpeforth.com> wrote in message
news:47b98c22.338328140@192.168.0.50...
I suspect that the OP is not interested in the Host Controller spec, but the
High Capacity spec. I don't think that there is one though. It is part of
the SD Spec version 2, which wasn't publicly available last time I looked.
However, I have managed to figure this out myself. The basic differences
are:
* In the initialization at ACMD41 say you support SDHC (0x40000000).
* In the CMD55 the reply should include SDHC support (0x40000000).
* All sectors are 512 bytes and can't be changed by CMD16.
* Offsets for reading and writing sectors are now sector numbers not bytes.
So in theory you can access cards with 512x mory memory.
* And the file system (as supplied) is FAT32.
I'm sure there is other stuff that I didn't need.
Peter
- Posted by Stephen Pelc on February 19th, 2008
On Tue, 19 Feb 2008 07:48:50 GMT, "Peter Dickerson"
<firstname.lastname@REMOVE.tesco.net> wrote:
What you need for HD is in the initialisation sequence diagrams.
However, as always reality intervenes when you test cards from
several different suppliers.
Stephen
--
Stephen Pelc, stephenXXX@mpeforth.com
MicroProcessor Engineering Ltd - More Real, Less Time
133 Hill Lane, Southampton SO15 5AF, England
tel: +44 (0)23 8063 1441, fax: +44 (0)23 8033 9691
web: http://www.mpeforth.com - free VFX Forth downloads
