Electrical Engineering Stack Exchange
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Questions tagged [microsd]

microSD is a physically smaller version of the Secure Digital (SD) memory card standard. It is also known as Transflash (TF) memory cards. It's currently the smallest form factor in the range with dimensions of 15 × 11 x 1 mm. Electronically Identical to full sized SD Cards and MiniSD cards

microSD is a physically smaller version of the Secure Digital memory card standard. It is also known as Transflash (TF) memory cards. It's currently the smallest form factor in the range with dimensions of 15 × 11 x 1 mm. Electronically Identical to full sized Cards and MiniSD cards

Tag should be depreciated due to lack of difference with other SD cards. Please use SD card tag.

31 questions
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How to do pulling up or down correctly when interfacing a microSD card?

I have seen people pulling up only the CS pin, so that when the microcontroller's pins are floating in the power-up, the microSD card is not corrupted. Also, I have seen many people pulling up and down DI,DO and SCLK lines. Some of the circuits that…
abdullah kahraman
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What is the correct command sequence for microSD card initialization in SPI?

I am trying to interface a microSD card (2 GB, Kingston, Sandisk) with a Silicon Labs C8051F931 controller. I am very much confused about the sequence which I have to follow for initialization. In the book SD Card Projects Using the PIC…
gpuguy
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Low power micro-SD card storage

We are building a low-power data logger based upon the ATmega328P, in order to make use of the Arduino boot loader and IDE, etc. Ideally power consumption should be less than 0.3mA @ 3.3V to get around 4 months life on a single AA battery. Sensor…
geometrikal
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Is SPI safe to be interrupted?

I'm writing to a microSD card from within my firmware, but it's the lowest priority task, so it can be interrupted by other tasks while it's in the middle of reading/writing. Now suppose I communicated with this microSD card using a UART. The…
Maestro
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Why is SPI Flash memory so limited in max size, and cost way more (per MB) than SD flash memory?

For example: SPI Flash largest size is 512MB at $9/ea: SPI Flash prices vs 2GB of microSD $3/ea (some with $1 shipping): microSD prices
jpeskin
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12
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How can so many memory cells fit on MicroSd card?

I just wondered, when I saw my new MicroSd memory card , how the hell can 32GB fit in that space? Simple math: it's around \$\frac{1}{2}cm^2\$ (my estimate, most of it is controllers anyway) and it contains 32GB cells. So…
Randalfien
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Are there problems accessing a microSD card via SPI when there are other slave SPI devices?

I'm working on a design that has a CPU with only one SPI port. I have multiple (3) slaves connected to this port, one of which is a microSD card. Here is a report from an engineer who says that SD cards are designed to operate as the only slave to…
jpeskin
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8
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Non-conductive pads in datasheet?

I'm designing a device which has a DM3CS-SF microSD connector and in the recommended land-pattern for the datasheet they have areas labeled as "Non-conducting traces". What am I suppose to do with these areas? Are these keep-out areas where I…
helloworld922
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MicroSD flash block size

I'm working on a low-power application with data storage on a microSD card. In the interest of minimizing power consumption, I'm planning to buffer data to RAM before writing, and I suspect that the optimal buffer size would be an integer multiple…
Alex K
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How to make a device in miniSD or microSD form factor?

I would like to design and get produced a device in miniSD or microSD card form factor. This is not actually a memory card, it just uses that connector. There are other devices like that, for example Electric Imp. I'm wondering what type of…
Alex I
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MicroSD with ECC

Some MicroSD cards (mostly Transcend) claim to have an ECC controller on the chip. I was wondering how this works? Do they verify all data written to it, and automaticly relocate the sectors to different positions in case they detect a mismatch? If…
Maestro
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How to detect SD Card Insertion Without Leakage Current

I'm using a TI CC1111 SoC to read/write a microSDHC SD card, with an Amphenol card socket. The card detect (CD) pin of the socket is connected to ground when no card is present. When a card is inserted, the connection is broken. (This seems to…
David
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RAM device that plugs into microSD slot?

I have a pair of small battery-operated self-logging 3-axis accelerometer devices that each use a microSD flash device for storage (the GCDC X250-2). Unfortunately, the devices do not buffer microSD writes, so the recorded data has frequent gaps. I…
BobC
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Developer/application board with a CAN/SD card

We have to develop a data logger. I should get some data over CAN (1 MBit/s), compress this data and save it to an SD card. To save time, we would prefer to use as much existing hardware and software as possible. I looked into Arduino (CAN and…
Fabian
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Ferrite bead for use for filtering a microSD card's Vcc

I am hoping to use a microSD card in an AVR project and am just trying to find values for all my components. However, I am not sure what value of ferrite to use here. The few microSD schematics that I've seen with a bead just said "FERRITE" and…
Inductiveload
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