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SD Memory Card Frequency Range

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Newbie level 5
Oct 13, 2007
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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.

sd card frequency

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

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.

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.

kingston sd frequency

This frequency is your own SPI or implemented one?

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.

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