generic memory card protocol

[shaiko]

Hello,

Do ALL TYPES of memory cards support the SDIO protocol ?

 

[tpetar]

Read this topic on this site maybe usefull :
https://www.edaboard.com/threads/68316/

 

[shaiko]

That's a long answer for a short question...Is there a SINGLE communication protocol that all memory cards MUST obay ?

 

[FvM]

A short answer is no and no to both questions.

For a more detailed answer, you should probably clarify what you mean with all memory cards.

 

[shaiko]

I want to implement an FPGA peripherial to communicate with small memory cards, like the ones used in digital camera's and cell phones...
Don't they all use the SDIO protocol ?

 

[tpetar]

**broken link removed**

 

[shaiko]

Let me rephrase the question...From all memory cards, is the SDIO protocol is the most spread protocol?

 

[tpetar]

Let me rephrase the question...From all memory cards, is the SDIO protocol is the most spread protocol?

Yes it is.

 

[FvM]

I hear some confusion. SDIO is not a memory card protocol. It's an extension of the SD-Card standard for IO purposes.

 

[shaiko]

So what is the name of the most common com protocol that most cards use?

 

[FvM]

You still didn't clarify, which kind of cards you have in mind.

You'll possibly decide for SPI mode, supported both by SD-Card and MMC.

 

[shaiko]

FvM,

I meant both SD and MMC card.
Do they ALL support SPI ? If not, what is the most common protocol they utilize?

 

[FvM]

According to the standards, SPI mode is mandatory for SD-Card and optional for MMC. A single data line SD/MMC transport protocol can be also used as a common subset of both standards.

 

[shaiko]

The bottom line is that I want to design a signle IP core that will be able to communicate with both SD and MMC cards.
You say that, SPI is mandatory only for SD cards and not for MMCs...So, Is there a standardized communication protocol that is mandatory for both types of cards (MMC and SD)?

 

[FvM]

As far as I'm aware of, all available MMC cards are supporting SPI. But I strictly quoted the standard.

According to my reading, the default SD/MMC transport over a single data line should work for both card types. But I never used it, so I can't tell from own experience.

 

[shaiko]

Secure Digital - Wikipedia, the free encyclopedia

The table at the bottom of the page, notes that SPI is optional for MMCs.
And only "1 bit" protocol is supported by ALL type of memory cards.

Where can I find the official specs of the "1 bit" protocol (timing, transaction descriptions, etc...) ?

 

[FvM]

The officlal standards aren't free. There are product manual from Sandisk, that contain most of the official standard. Unfortunately Sandisk has stopped publisjing them as far as I'm aware of.

P.S.: More specifications from Edaboard
https://www.edaboard.com/threads/155726/
https://www.edaboard.com/threads/60274/

 

[shaiko]

thanks for the info

 

[clavemartin]

SD card has standard removable memory storage with the interface support of electronic applications...other competing standards memory storage components are CF, CF+, Sony Memory Stick, and USB... Same as for the SIDO card ...