Searching \ for '[EE] SDHC Cards, was Re: Digital Sound' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/io/audio.htm?key=sound
Search entire site for: 'SDHC Cards, was Re: Digital Sound'.

Exact match. Not showing close matches.
PICList Thread
'[EE] SDHC Cards, was Re: Digital Sound'
2008\07\17@061801 by Alan B. Pearce

face picon face
>Most SD and MMC cards can communicate using SPI,

Does anyone know if the new SDHC cards that seem to have cropped up for use
as higher capacity storage in digital cameras also have the SPI interface?

2008\07\17@065248 by Xiaofan Chen

face picon face
On Thu, Jul 17, 2008 at 6:17 PM, Alan B. Pearce <spam_OUTA.B.PearceTakeThisOuTspamrl.ac.uk> wrote:
>>Most SD and MMC cards can communicate using SPI,
>
> Does anyone know if the new SDHC cards that seem to have cropped up for use
> as higher capacity storage in digital cameras also have the SPI interface?

It seems to me that SPI interface is still there.
Example: http://www.pqi.com.tw/upload/download/mini%20SDHC.pdf

Xiaofan

2008\07\17@072300 by Alan B. Pearce

face picon face
>It seems to me that SPI interface is still there.
>Example: http://www.pqi.com.tw/upload/download/mini%20SDHC.pdf

Ah thanks Xiaofan. I hadn't actually gone looking as yet, but that will suit
my requirements admirably. Looks to have an unusually complete interface
spec for an SD series device sheet that is publicly available.

2008\07\17@080216 by William \Chops\ Westfield

face picon face

>> Does anyone know if the new SDHC cards that seem to have cropped  
>> up for use
>> as higher capacity storage in digital cameras also have the SPI  
>> interface?

Note that the 2Gbyte size where normal SD tops out is by definition  
close to
3 hours of CD-quality stereo sound.

(However, I've seen assorted things that claim to top out at 1GB;  
perhaps
above that is where you need FAT32 instead of FAT16?  (Microsoft SAYS  
Fat16
is good up to 2G...)

BillW

2008\07\17@084306 by Nicola Perotto

picon face
It's is possibile to have a 4GB partition FAT16 using 64KB/cluster but
this is not compatible with win98 and older.


William "Chops" Westfield wrote:
{Quote hidden}

2008\07\17@085753 by Alan B. Pearce

face picon face
>>> Does anyone know if the new SDHC cards that seem to have cropped
>>> up for use
>>> as higher capacity storage in digital cameras also have the SPI
>>> interface?
>
>Note that the 2Gbyte size where normal SD tops out is by definition
>close to 3 hours of CD-quality stereo sound.

Dunno 'bout that, but when taking digital photos in RAW mode, one needs some
hefty memory space, which seems to be where the SDHC cards are aimed. They
seem to start at 4GB, and go on up.

I assume this means they use a different file system than the SD cards,
something more like NTFS, or one of the *nix types maybe, that can handle
the larger volumes.

2008\07\17@103343 by M. Adam Davis

face picon face
On 7/17/08, Alan B. Pearce <.....A.B.PearceKILLspamspam@spam@rl.ac.uk> wrote:
> Dunno 'bout that, but when taking digital photos in RAW mode, one needs some
> hefty memory space, which seems to be where the SDHC cards are aimed. They
> seem to start at 4GB, and go on up.

They are primarily being positioned as the next stage in digital video
media.  I just purchased a Canon HF100*, which is a 1080 HD camcorder
that records directly to SDHC at up to 17Mbits/S (about 1 hour at
highest resolution, best quality on an 8GB SDHC card).  SDHC has
further specifications called "classes" which, IIRC, indicate the
Mbytes/S.  This camera, for instance, requires a class 4 SDHC card for
the highest recording bandwidth, but can use class 2 (slower) for all
others.  Big advantages over over media: no mechanical noise
associated with recording to DV tape or DVD disk, lower power read and
write, works directly in common (cheap) flash memory readers.

They are dropping in cost, though a DV tape or miniDVD is still
cheaper.  $25 for a cheap 8GB class 6 SDHC card vs $2 for a cheap
miniDV tape (11GB), $5 for a dual layer mini-dvd (2.8GB).

> I assume this means they use a different file system than the SD cards,
> something more like NTFS, or one of the *nix types maybe, that can handle
> the larger volumes.

No, they are still primarily FAT32 - it has the greatest compatibility
across computing platforms, and is simple and royalty free.  The SDHC
spec, I've heard, limits the cards to 32GB or less, but the interface
and the filesystem could allow for higher capacities, and my suspicion
is that it won't be too long before they officially accept much larger
capacities, though I'm sure manufacturers will start producing such
cards before then.

-Adam

* Yes, it's a very nice camcorder, which I wouldn't have purchased
except that Embedded Systems does, in fact, give out the $500 amazon
gift certificates for survey participation that they say they do.
Given the number of surveys I've filled out over the years, though, I
doubt that I'm made much more than $5-10 per hour.  Still an
unexpected and very pleasant surprise.

--
EARTH DAY 2008
Tuesday April 22
Save Money * Save Oil * Save Lives * Save the Planet
http://www.driveslowly.org

2008\07\17@105518 by Bob Ammerman

picon face
> They are primarily being positioned as the next stage in digital video
> media.  I just purchased a Canon HF100.....


My son wants to buy that model. Could I ask you your opinion of it?

-- Bob Ammerman
RAm Systems

2008\07\17@111541 by Alan B. Pearce

face picon face
>> Dunno 'bout that, but when taking digital photos in RAW mode, one needs
>> some
>> hefty memory space, which seems to be where the SDHC cards are aimed.
>> They
>> seem to start at 4GB, and go on up.
>
>They are primarily being positioned as the next stage in digital video
>media.  I just purchased a Canon HF100*, which is a 1080 HD camcorder
>that records directly to SDHC at up to 17Mbits/S (about 1 hour at
>highest resolution, best quality on an 8GB SDHC card).

Thanks for the explanation Adam. My interest is in getting a Canon 450D SLR
if I can sort out the finance, which also uses SD/SDHC cards, so I was
interested to see how the interface had changed.

Alan

2008\07\17@112216 by Harold Hallikainen

face
flavicon
face

> (However, I've seen assorted things that claim to top out at 1GB;
> perhaps
> above that is where you need FAT32 instead of FAT16?  (Microsoft SAYS
> Fat16
> is good up to 2G...)
>
> BillW


>From Wikipedia:
In 1988 the improvement became more generally available through MS-DOS 4.0
and OS/2 1.1. The limit on partition size was dictated by the 8-bit signed
count of sectors-per-cluster, which had a maximum power-of-two value of
64. With the standard hard disk sector size of 512 bytes, this gives a
maximum of 32 KB clusters, thereby fixing the "definitive" limit for the
FAT16 partition size at 2 gibibytes. On magneto-optical media, which can
have 1 or 2 KB sectors, the limit is proportionally greater.

Much later, Windows NT increased the maximum cluster size to 64 KB by
considering the sectors-per-cluster count as unsigned. However, the
resulting format was not compatible with any other FAT implementation of
the time, and it generated greater internal fragmentation. Windows 98 also
supported reading and writing this variant, but its disk utilities did not
work with it.

So, it appears the 2GB limit is because the sectors per cluster byte in
the boot sector is considered to be unsigned (limiting us to 127 sectors
(each 512 bytes) per cluster. However, the number of sectors per cluster
also has to be a power of 2, dropping us down to 64 sectors per cluster.
That's 32kB per cluster. With 16 bit FAT entries, you can have about 64K
clusters (65,536 minus some reserved values), limiting the disk (actually,
the partition) to 2GB.

Apparently NT considers the SectorsPerCluster byte to be unsigned,
allowing a number up to 255, but still required to be a power of 2, so we
are up to 128 sectors per cluster for 4GB per partition.

The requirement that the sectors per cluster be a power of two is probably
to make the math easier (shift instead of a complicated multiply), but it
would be interesting to see what happens if you set it to some other
number (like 255), or if you were to interpret zero sectors per cluster as
256 sectors per cluster.

Further, the sector size is normally 512 bytes, but does not necessarily
have to be. Wikipedia says some magneto-optical disks have sector sizes of
1kB or 2kB. The bytes per sector is defined as a 16 bit number in the boot
sector, so you could make it really big if you wanted. As I recall from
writing some MMC/SD card code years ago, you pass an actual byte address
(not a sector number) into the card, so the card itself does not care
about sector size (though I think there is a configuration register with
bytes per sector).

Increasing the bytes per sector or the sectors per cluster works well with
large files, but with a lot of small files, you have a lot of wasted
space.

Finally, you can always do multiple partitions on a card to cram even more
data on the card.

Harold

--
FCC Rules Updated Daily at http://www.hallikainen.com - Advertising
opportunities available!

2008\07\17@115015 by Alan B. Pearce

face picon face
>Increasing the bytes per sector or the sectors per cluster works well
>with large files, but with a lot of small files, you have a lot of
>wasted space.

<VBG> Not normally a problem with video and digital still pictures ... ;)

2008\07\17@123948 by olin piclist

face picon face
M. Adam Davis wrote:
> I just purchased a Canon HF100*, which is a 1080 HD camcorder
> that records directly to SDHC at up to 17Mbits/S (about 1 hour at
> highest resolution, best quality on an 8GB SDHC card).

Nice choice.  I just got one of those for my son as a birthday and high
school graduation present.  He's home right now learning how to use it and
the software.  I'm interested to see what he'll have to show me this evening
(and whether he did any mowing of the lawn like he was supposed to, but
that's another issue).  I spent probably half a day looking at available HD
camcorder choices and eventually decided on the Canon HF100 too.  The 16Gb
built into the HF10 for $200 more seemed silly when I got 16Gb removable for
the HF100 for $50.  There was a Panasonic that initially looked good, but
not after reading some reveiws.  It's good to see someone else came to the
same conclusion.  This is a rapidly moving field where a few months makes a
significant difference.

> They are dropping in cost, though a DV tape or miniDVD is still
> cheaper.  $25 for a cheap 8GB class 6 SDHC card vs $2 for a cheap
> miniDV tape (11GB), $5 for a dual layer mini-dvd (2.8GB).

Yeah but tape needs to be futzed around with, takes space and power, makes
noise, is less reliable than flash, and can't easily be read from a PC
except thru the camera.  Flash has a finite number of writes, but you'd wear
holes in a tape long before that number.  Considering the price of the
camcorder, I didn't mind $50 for a card to hold 2 hours of HD video at the
highest resolution and lowest compression.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.

2008\07\17@131023 by Alan B. Pearce

face picon face
(and whether he did any mowing of the lawn like he was supposed to,
>but that's another issue).

Hmm, high school students are the same the world over ... ;)))

>Flash has a finite number of writes, but you'd wear
>holes in a tape long before that number.

and the possibility of the tape screwing up in the cassette because it
didn't load properly, or the servo system screwed up on the player or the
electronics went faulty write only or ...

OK, the last one can possibly happen to a flash card, and there is a variant
on loading properly where the contacts get screwed up ... etc, but on the
whole I think I do prefer solid state.

More... (looser matching)
- Last day of these posts
- In 2008 , 2009 only
- Today
- New search...