Need a SD (memory card) controller chip.

Do you mean something like this?

Marc

Boki =BCg=B9D=A1G

Dear All,

Due to the cost, I hope it only support SD ( no need to suppor others, ex: CF, MMC,...).

Best reagrds, Boki.

Or this :

Have a look at their support forum first, whether it really works as announced, as later support is slow to non-existent.

Rene

SD cards must support the SPI interface. So any microcontroller with a built in SPI interface can control an SD card.

You can download the MMC card spec from SanDisk to get the details.

The MMC spec is not the same as the SD spec, unfortunately. One can get a copy of the minimal SD spec for free but not the whole spec without joining the club. The entire spec is necessary to fully implement SD.

I am using a device from Winbond that supports SD and SDIO, but I had to sign NDAs to get the source. I have no doubt you will run into the same issue.

Cheers

PeteS

Have a look at

and related:

I heard that:

1. SD is a superset of MMC, thus MMC code can use SD cards
2. The 4-bit SD interface isn't a big deal
3. Only the 'secure' aspects are closely guarded
4. The security has been cracked, so it isn't secure
5. Almost nobody uses the security features

So I presume one can get code to use SD cards without the complete specification.

PeteS =BCg=B9D=A1G

built

Thanks a lot, I think NDA is not an issue. :)

Best regards, Boki.

SD is a superset of MMC, and AFAIK all SD cards ( except maybe the very big ones) can be treated as MMC cards unless you want the SD-specific features.

I think you have to pay significant $ to join the SD card club to get the formal SD specs

SD memory cards specs were based on MMC specs but MMC specs have progressed many versions since then and SD have moved on to v2.0 too. I think there are MMC cards that can work in SD slots but there are no guarantees anymore. I've only done a two minute test with an MMC card in my own SD card interface (for an analytical instrument). It was not recognised - haven't had time to find out why.

Peter

I think you've got it backwards. SD cards wil work in MMC slots in most cases. If an MMC card works in an SD slot it is only because the device supports MCC as well (or only uses MMC mode, even for SD cards, this avoids the NDA issue).

Your instrument seems to support SD mode only, so MMC will not work.

I dont think he will run into the same issues , nor will i .

The market will be free , or it will die , take your pick ....

Patents hold society hostage by those who only copyied others , but got to patent office first ! Can You say Bill Gates !

The standard SD card is thicker than the MMC card so there ought to be a mechanical problem with putting SD into an MMC-only slot.

I have now found a pointbin the SD spec that says if such-and-such fails then treat as MMC card. So it looks like need to look more carefully at MMC if I want to support that.

Peter

Ah, forgot about the thickness issue. But why would anyone implement an mmc only slot instead of one that will also accept SD? These days, SD is a lot more common than MMC and limiting yourself to MMC does not seem logical. Maybe in rare cases where the 0.7mm difference is a problem, it's an option but then you could also investigate mini SD and thin SD.

I badly need a replacement "Miniature card" for a device of ca. 1998. It's 3.3/5V, 2MB but I've read that the pin-out will handle up to 32 MB. Previous goog-searches suggested that "Miniature cards" were initiated by Intel, but were soon replaced by other standards and are no longer available, except from eg. Cisco at exhorbitant prices.

Can some one point me to a source ?

== Chris Glur.

Do you have a link to the Cisco version ??