Electrical Engineering Stack Exchange
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Questions tagged [sd]

Secure Digital (SD), a memory card standard. Has multiple form factors (Standard, MiniSD and microSD/TransFlash) and multiple capacity ratings (SDSC, SDHC, and SDXC). Also extends to SDIO, which allows peripherals in an SD form factor to attach to a host, similar to USB.

Secure Digital (), a memory card standard. Has multiple form factors (standard, miniSD and /TransFlash) and multiple capacity ratings (SDSC, SDHC, and SDXC). Also extends to SDIO, which allows peripherals in an SD form factor to attach to a host, similar to .

microSD is a physically smaller version of the Secure Digital (SD) memory card standard. It's currently the smallest form factor in the range with dimensions of 15 × 11 x 1 mm. Electronically, it is identical to full-sized SD cards and MiniSD cards.

MMC cards are similar, and pin compatible, though the protocol is different. SD competed with CompactFlash cards, though it has widely won out as the go to flash card standard.

Further reading:

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Is it true that a SD/MMC Card does wear levelling with its own controller?

I can't find any reliable information about this. I don't have the full specification of the SD/MMC Card hardware. Is it true? My high-level application doesn't need to be concerned with wear leveling when working with these cards? EDIT Could…
ivarec
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Do I need to pay royalties to the SD card people if my device "just happens" to be compatible with SD cards?

I'm designing something which will use an SD card. The device will be able to read and write the cards, using publicly available specifications. Do I need to pay the SD card people?
Thomas O
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MMC/SD card interface - any access to wear levelling info? (counters, etc)

I don't suppose there's something in the MMC/SD card specification for retrieving any information on erase counts on an MMC/SD card, is there? My goal is to get my embedded system to avoid writing to metadata like last access or modified times,…
darron
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How can I hardware protect a microSD from writing to

I have a beagle bone black board and I want to make the card read-only so no modifications go to the microSD card. How can I achieve that? I have searched over internet for this. SD card have a switch to do this, however microSD does not. I am…
codiac
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What do OD and PP stand for in SD card frequency fOD and fPP?

It seems all SD card specifications mentioned two frequencies (fOD and fPP) as used in identification and data transfer mode respectively. What do the subscripts (OD and PP) mean?
bruin
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MicroSD card won't return any data on read command

I just want to clarify with everyone that I have exhausted all of my search options looking for an answer, and still cannot find the answer to my problem. I am trying to interface a micro sd card slot with my pic32 project by bit banging an spi.…
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SD card via SPI: pull-up resistors or dedicated IC?

It's common to find SD card connected to MCU via pull-up resistors, like in the schematics above: Recently I have read that newer SD card to achieve high write/read speeds needs to have sharps edges which, are not achievable with pull-up…
aster94
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SD card protected area

Explanations of the "protected area" functionality are very brief and I want to know more. Is it in anyway related to CPRM? Does it use the whole card or part of it? Is it a form of write protection? How can I set one up?
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Micro SD cards & T-flash?

Something interesting I've noticed with cheap devices from China (such as iPhone clones and digital cameras and the like) is that the manuals always specify they are "T-flash" (TransFlash) compatible, instead of "microSD" or "SD" compatible. Is this…
Thomas O
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SD card reader, had to add 1kΩ resistors to make it work. Why?

I was having a problem making my SD card reader work with Arduino Mega. I tried a lot of things to no avail until I read somewhere that I should try putting a 10 kΩ or 1 kΩ resistor in series with the MOSI and SCLK pins. But for some reason in my…
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microSD card, how many times can I write the same sector?

I'm using a microSD card in an embedded system which use a microcontroller interfacing with the microSD card using SPI. I do raw data write, without a file system. Every time that I want to store data, I write an entire block of 512 bytes. I write…
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Do I Need to Buy Full SD Specification

I'm designing a system with an ARMv7 processor. My host processor support SDIO protocol and I wish to use this unit to connect the host to a Memory card and a WiFi module that both are compliant with SDIO Card Specification Version 2.0 My question…
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How to add a password to an SD card?

I want to build an embedded system that reads external data and logs it to a file saved in an SD card. However this system is accessed through a password and I want either the SD card or the file in it to use this password as well. How can I do…
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Is the slide-lock on an SD card optional?

When enabling the write lock on the side of an SD card, is the write protection a physical limit on the SD card, or a flag sent to the reader or OS telling it to please not write?
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Calculating SD card size from C_SIZE in CSR

I'm guessing I'm just reading something incorrectly here, but I can't make this add up. From the SD card spec, section 5.3.3 tells us how to calculate card size (C_SIZE) from the data in CSR (CMD9 response): So first, my "32GB" card gives this…
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