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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.

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51
votes
7answers
45k views

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 ...
24
votes
5answers
8k views

Do I need to pay royalties to the SD card people if my device “just happens” to be compatible with SD cards? [closed]

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?
19
votes
2answers
8k views

Do all microSD cards support SPI mode?

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 ...
18
votes
6answers
43k views

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. ...
18
votes
4answers
11k views

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 ...
18
votes
6answers
6k views

How do I protect SD card against unexpected power failures?

I am working on a device that uses the Microchip MDDFS library to store data to an SD card. The logger will log data at a maximum rate of 1 entry (56bytes) every minute. The problem is the device may ...
17
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2answers
2k views

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 ...
16
votes
2answers
11k views

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
16
votes
1answer
13k views

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 ...
14
votes
1answer
1k views

How can V-USB screw up the built-in SPI of an ATmega328p?

I'm working on a V-USB project that shows up as a Keyboard using an ATmega328p. The USB part is working great (it's not my first V-USB project), but after I start the V-USB stack with ...
13
votes
11answers
12k views

How to make 1 bit permanent memory circuit?

I would like to make a simple circuit to store or save 1 bit of data. The circuit should be able to remember the state of an LED ( on or off ) even if the supply is disconnected from the circuit. I ...
13
votes
7answers
7k views

Saving data to an SD card memory module using an Arduino

Is it possible to save data from the Arduino to an SD card memory module?
12
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2answers
8k views

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 ...
10
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3answers
3k views

Anyone either read japanese or know about laying tracks for a micro SD card slot?

I'm trying to include a micro SD card slot in a project I'm working on and I'm having a little trouble with the datasheet. Unfortunately I don't read japanese. Just wondering what the text says in ...
10
votes
7answers
6k views

Why is data stored on a NAND chip irretrievable if cracked?

All data recovery companies, regardless of skill, unanimously say that if the memory chip of a device has just a hair line crack, data recovery is impossible. Not unlikely, not expensive, but ...
10
votes
1answer
2k views

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 ...
9
votes
4answers
17k views

Does magnetism affect SD cards?

Would a strong magnet have any effect whatsoever on a thumb drive (I'm assuming not) or on an SD card? It seems unlikely, but I'm hoping someone can give me a definitive answer, since I'd rather not ...
9
votes
1answer
4k views

Does an SD card in SPI mode respect chip select/slave select? Seems to be resetting in my application

I have an application where I have a microcontroller (NXP LPC1343) which is connected to an FPGA via 16-bit SPI. There is also an SD card using the same SPI port (MISO/MOSI) but with a different CS/SS ...
9
votes
3answers
551 views

FSInit() - “CE_BAD_PARTITION” [closed]

I am using a PIC18F26K80 and an XC8 compiler. I am trying to initialise an SD card and create a file. I have simply formatted the SD card on Windows to have a "FAT32" file system and an "Allocation ...
8
votes
1answer
441 views

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 ...
7
votes
4answers
1k views

Embedded system scripting [closed]

Does anyone have some cool ideas for a use of a scripting language on an embedded system? I'm thinking about the eLua project specifically. Basically, you need a micro with at least 64k of RAM, ...
7
votes
2answers
791 views

What does it mean when components in schematics do not connect?

I'm fairly new to the whole Arduino world, and I'm just really curious about this schematic that I came across... I can read the basics of a schematic, but this one has me puzzled. What are the ...
7
votes
2answers
26k views

Difference between 1-bit, 4-bit and 8-bit SDIO

Please help me understand the significance of 8-bit SDIO over 1-bit and 4-bit SDIO. Let me know the pros and cons of each type. Wiki or SDIO specification document does not discuss this.
7
votes
2answers
9k views

Is it possible to use 4-pin mode for an SD card with a microcontroller instead of SPI mode?

Is it possible to use the 4-pin mode of an SD card when designing an interface with a microcontroller, or must you always use SPI mode? I am particularly thinking of a microcontroller such as a PIC24. ...
7
votes
2answers
3k views

What does SWITCH pin do on a microSD connector?

I'm trying to connect a microSD card connector to my project (Molex 502774) and am slightly confused by the extra pins (nails?) provided. One of them is marked DETECT NAIL and the other one is SWITCH ...
7
votes
2answers
5k views

Micro SD card power circuit failure

Description I am designing a system in which there's a circuit that controls the power applied to a micro SD card (enable/disable). The circuit is the following: The power control circuit is done ...
7
votes
1answer
1k views

Occasionally the first byte of data from an SD card SPI read is bad

The device I am developing is an SD card storage add-on to a retro computer, SanDisk Ultra II 1.0 GB SD card in an SD card socket (I have no idea if the brand is significant, it just happens to ...
7
votes
1answer
2k views

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 ...
7
votes
1answer
658 views

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 ...
7
votes
1answer
1k views

Are there any SD cards optimized for single block read/writes?

I have used SD cards for several embedded applications over the years. However, as cards have gotten larger, the single block read and write speeds have dropped. I suspect this is largely because ...
7
votes
2answers
486 views

Conformal coating and micro SD card sockets

I have a embedded computer design which uses a low profile micro sd card socket as an extra option in addition to an on board solid state disk as storage/booting mediums. In manufacture the board is ...
6
votes
3answers
3k views

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 ...
6
votes
1answer
4k views

Problems reading data from a microSD card

I am trying to read a block of data from a standard capacity micro SD card, but the received data does not make any sense. Here is what I'm doing: Initializing the card Reading data Setting CS low ...
6
votes
1answer
6k views

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 ...
6
votes
1answer
2k views

SD card access slows down with many files

I'm working on a data logger application using a MSP430F5529 running at 2 MHz and a SD card using FatFs. The SPI interface is already running at maximum frequency. However I am seeing very erratic ...
6
votes
2answers
4k views

Diagnosing SD card failures

I have an embedded device using an SD card. Occasionally I see SD cards fail, and I need to understand the failure mode. Are there tools, perhaps for specific manufacturers, that help me understand ...
5
votes
3answers
9k views

Is it possible to use an SD card without a file system?

I'm doing a project on PIC, which needs a large amount of memory to store data. I want to use an SD card as the memory storage element. I don't want any type of file system. I googled the interfacing ...
5
votes
4answers
642 views

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 ...
5
votes
6answers
2k views

SDHC card, a microSD shield, and Arduino Duemilanove

I got a new microSD shield from LittleBird and am having some troubles with it. I downloaded the sample library that it said to used, threw in a microSD card and expected it to work... It won't ...
5
votes
2answers
4k views

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 ...
5
votes
1answer
263 views

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 ...
5
votes
1answer
7k views

SD card read/write problems in SPI mode

I am working on an NEC v850ES/JH3 controller for testing an SD card driver in SPI mode. We interfaced the SD card slot directly to the v850ES/JH3 controller without any pull-up resistors. Does it have ...
5
votes
2answers
652 views

Embedded PC with Gigabit Ethernet and SD card interface? [closed]

Where do I find such a module? All of the embedded PC modules I've seen so far have only a slow 10/100 Mbit/s Ethernet interface. This is for a scanner application. I get incoming data at a rate of 2 ...
4
votes
2answers
7k views

How about soldering microSD card directly to PCB?

I know that microSD cards are typically not designed for this type of use, but has anyone tried this? Would it be possible in production ( >1000 units), that is, would any PCBA service be able to do ...
4
votes
5answers
8k views

SD card emulation

Problem description: I've built a MSP430F2370 based 15693 RFID tag reader/writer . The main board has a daughter board, shaped as a SD card, which connects to a SD card holder/reader. We were ...
4
votes
2answers
2k views

SD card as ROM memory in a microcontroller

Can I use an SD card as ROM for my microcontroller? What other options are there if I want a large amount of ROM memory (cheap)?