SD Memory Card Frequency Range

[prabhu.er]

sd card initialization time

Dear All,

During Initialization (SD Memory Card) procedure what is the frequency range.

Most of the document tell the frequency range is 100KHz - 400KHz (MMC Compliant).

My doubt is MMC Card working open drain mode during initialization so it should operate
100KHz - 400KHz.
But SD Memory card always push pull mode so it can work any frequency range (i.e 0 - 25MHz Default Speed Mode). that is SD Memory Card did not have any frequency restriction during initialization time.

My point is correct? please any one help me.

 

[ljxpjpjljx]

mmc frequency

which type do you use?

 

[prabhu.er]

sd card frequency

I am using 2GB Kingston SD Card. Normal Size. ( i am did not use mini SD or micro SD Card).

 

[yinchai2]

sd card 400khz

I guess you are right if you know ahead of time that the card is SD type. In general, the enumeration process includes figuring out the type of card instead (SD/MMC/HSMMC.....), so you need to run a slower clock initially.

 

[prabhu.er]

sd memory card ranges

So, I am come to the following conclusion.

If I am using only (I am not going to use MMC or other type of card) SD Memory Card I can use any frequency ( 0 - 25MHz SD Card) during initialization procedure.

 

[bednyk]

kingston sd frequency

This frequency is your own SPI or implemented one?

 

[prabhu.er]

memory frequency

If your using only SD Memory Card do not worry about Initialization frequency ( 0 - 25MHz). If you supporting multiple type of Cards ( SD and MMC) initialization frequency should be 100KHz to 400KHz.

In my case I am only using SD Memory Card so I can select any frequency range within 0 - 25MHz.

Thank very much to all.