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Have you ever encountered an SD card which does not support the SPI mode?

I know microSD are not required to but I believe all do support SPI.

EDIT: The information about optionality of SPI seems to come from Wikipedia and was recently removed (here and here).

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  • \$\begingroup\$ Could you provide some citation to your knowledge that microSD cards aren't required to support SPI? \$\endgroup\$ – Nick T Mar 22 '11 at 15:14
  • \$\begingroup\$ I feel like the guy who was editing it wasnt sure himself based off of the wording and changes made. \$\endgroup\$ – Kellenjb Mar 22 '11 at 16:32
  • \$\begingroup\$ OTOH the guy adding this information did not back it up in any way (it appeared in one big edit to the whole article). Quick google searching also did not reveal anything that would support the optionality of SPI. \$\endgroup\$ – jpc Mar 22 '11 at 16:34
  • \$\begingroup\$ Even if the standards require it, I wouldn't expect some of the cheap direct from china cards to meet the standards... \$\endgroup\$ – Grant Aug 30 '12 at 12:24
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According to the Wikipedia article, all families of SD cards support SPI and furthermore, most MMC cards do as well. In the SD 2.00 specification [PDF], I don't see anything that states that it's optional, though nothing says it's mandatory either.

However, the specifications seem to keep separate the electrical properties and mechanical form factors (SD, miniSD, microSD), so there should be no electrical difference between any SD card mechanical package unless mentioned separately (e.g. SD vs. SDHC).

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  • \$\begingroup\$ I added the source of the SPI optionality information. So you are probably right. I would like to wait a few days before accepting the answer (if you don't mind) in case someone finds more information. \$\endgroup\$ – jpc Mar 22 '11 at 15:27
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The most basic requirement of the SD standard is that the memory subsystem MUST support the SPI mode of transfer. You can bet your tushy that an SD device will support SPI mode (that includes the microSD too).

I am an embedded engineer and have implemented microSD in a number of designs all in SPI mode.

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