Hi All, 1. I'd like the executive summary of the differences between the SD and SDHC memory interfaces. My assumptions the connection interface is the same and the physical interface is the same except the speed and protocol. 2. microSD is the same as SD except the microSD is physically smaller. Any pointers would be appreciated. Thanks Joe

SD snd SDHC card differences
Started by ●January 1, 2010
Reply by ●January 1, 20102010-01-01
"Joe G (Home)" <joe.g@optusnet.com.au> wrote in message news:4b3db65b$0$5420$afc38c87@news.optusnet.com.au...> Hi All, > > 1. > I'd like the executive summary of the differences between the SD and SDHC > memory interfaces. > > My assumptions the connection interface is the same and the physical > interface is the same except the speed and protocol. > > 2. microSD is the same as SD except the microSD is physically smaller. > > Any pointers would be appreciated. >http://www.sdcard.org/developers/tech/ Regards, Chris Burrows Armaide: ARM Oberon-07 Development System http://www.cfbsoftware.com/armaide
Reply by ●January 1, 20102010-01-01
"Chris Burrows" <cfbsoftware@hotmail.com> wrote in message news:00c75f2a$0$15571$c3e8da3@news.astraweb.com...> "Joe G (Home)" <joe.g@optusnet.com.au> wrote in message > news:4b3db65b$0$5420$afc38c87@news.optusnet.com.au... >> Hi All, >> >> 1. >> I'd like the executive summary of the differences between the SD and SDHC >> memory interfaces. >> >> My assumptions the connection interface is the same and the physical >> interface is the same except the speed and protocol. >> >> 2. microSD is the same as SD except the microSD is physically smaller. >> >> Any pointers would be appreciated. >> > > http://www.sdcard.org/developers/tech/ > > Regards, > Chris Burrows > > Armaide: ARM Oberon-07 Development System > http://www.cfbsoftware.com/armaide > >Yes, but what are the technical "executive summary" between the two standards? What are the physical differences? What are the protocol differences? Could a software derived SD controller be re-written if the software and hardware was fast enough meet SDHC speed requirements? I ask these questions becuase http://www.sdcard.org/developers/tech/ doesn't go in to protocol detail - as I asked in my original question. Joe
Reply by ●January 1, 20102010-01-01
On Jan 1, 9:34=A0am, "Joe G \(Home\)" <jo...@optusnet.com.au> wrote:> Yes, but what are the technical "executive summary" between the two > standards?The executive summary is a PowerPoint presentation that says "SDHC newer, different logo fees apply". Right under that is a second bullet point that says "SDXC obsoletes SDHC".> What are the protocol differences?Mainly addressing mode changes so that larger cards can be supported. Yes in general an SD implementation can be upgraded to SDHC by software only. Also microSD to SD adapters are passive, so yes they are identical apart from form factor (no write protect switch on microSD)
Reply by ●January 1, 20102010-01-01
On Jan 2, 3:55=A0am, larwe <zwsdot...@gmail.com> wrote:> On Jan 1, 9:34=A0am, "Joe G \(Home\)" <jo...@optusnet.com.au> wrote: > > > Yes, but what are the technical "executive summary" between the two > > standards? > > The executive summary is a PowerPoint presentation that says "SDHC > newer, different logo fees apply". Right under that is a second bullet > point that says "SDXC obsoletes SDHC". > > > What are the protocol differences? > > Mainly addressing mode changes so that larger cards can be supported. > > Yes in general an SD implementation can be upgraded to SDHC by > software only. > > Also microSD to SD adapters are passive, so yes they are identical > apart from form factor (no write protect switch on microSD)Great thanks. I see the short form version of the SD specification has been released but not the SDHC, as I could not find it anywhere. Joe
Reply by ●January 1, 20102010-01-01
Un bel giorno Joe G (Home) digit�:> 2. microSD is the same as SD except the microSD is physically smaller.The only remarkable difference that I know is that the support of SPI mode (which is very handy for small microprocessors applications) is only optional for microSD. -- emboliaschizoide.splinder.com
Reply by ●January 1, 20102010-01-01
On Jan 1, 12:04=A0pm, dalai lamah <antonio12...@hotmail.com> wrote:> > 2. microSD is the same as SD except the microSD is physically smaller. > > The only remarkable difference that I know is that the support of SPI mod=e> (which is very handy for small microprocessors applications) is only > optional for microSD.This is true but in practice I have never seen one that took advantage of this. They appear to be identical dice in different packages. Some of the Chinese SDHC cards I've bought are in fact bonded onto a PCB that can be cut in one place as microSD and one place as SD form factor :)
Reply by ●January 1, 20102010-01-01
On Jan 1, 11:57=A0am, "Joey.G" <jjoey.g...@gmail.com> wrote:> I see the short form version of the SD specification has been released > but not the SDHC, =A0as I could not find it anywhere.SD (all flavors) is a buyware spec, gotta pay to join the club. But of course you can find everything you need by browsing around the Internet, it's just a matter of collating it all.
Reply by ●January 2, 20102010-01-02
Un bel giorno larwe digit�:>> The only remarkable difference that I know is that the support of SPI mode >> (which is very handy for small microprocessors applications) is only >> optional for microSD. > > This is true but in practice I have never seen one that took advantage > of this.Then I must be very unlucky, I tried with a single microSD and it didn't work. :) I don't remember the brand now. It could be Sandisk but I may be mistaken. -- emboliaschizoide.splinder.com
Reply by ●January 10, 20102010-01-10
In article <yc2qquzup029$.1no0v6dzwv9fs.dlg@40tude.net>,=20 antonio12358@hotmail.com says...> Un bel giorno larwe digit=F2: >=20 > >> The only remarkable difference that I know is that the support of SPI =mode> >> (which is very handy for small microprocessors applications) is only > >> optional for microSD. > >=20 > > This is true but in practice I have never seen one that took advantage > > of this. >=20 > Then I must be very unlucky, I tried with a single microSD and it didn't > work. :) >=20 > I don't remember the brand now. It could be Sandisk but I may be mistaken=. SanDisk MicroSD does support SPI mode. I was not able to get SPI=20 mode to work reliably with a Kingston MicroSD. --Gene
