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.
-3
votes
2answers
209 views
Small device that runs Linux [closed]
I want to make a small device that boots Linux off of an SD card for ARM or x86. I am trying to build this from scratch. I downloaded Linux (kernel.org) and compiled it on Ubuntu.
What kind of SD ...
13
votes
2answers
253 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 ...
1
vote
0answers
60 views
MicroSDHC WP_VIOLATION stuck on
I have a few 8 gigabyte MicroSDHC cards that are being used as the nonvolatile storage in a data logging hardware application. The data being stored is going to be in a raw format, rather than in a ...
2
votes
1answer
71 views
Buffering Micro-SD data for power saving useful?
I have a datalogger which has only 4KB of SRAM, and because of that it needs to flush its buffer to MicroSD every second. Would adding external SRAM to create a larger buffer safe any significant ...
3
votes
1answer
101 views
Advantage of SanDisk iNAND?
I'm looking for a low-power microSD card for a datalogger, when I came across SanDisk's iNAND technology. What are some real-world advantages of those vs. microSD cards, except for their smaller ...
0
votes
3answers
366 views
Interfacing microSD with LPC1769 Board
So we're trying to store bytes (from an A/D converter) of data into a SanDisk 1Gb microSD card from a LPC1769 microcontroller board using the on-board SPI protocol. I know how all that stuff works, ...
3
votes
2answers
260 views
Reliable secondary storage for Raspberry Pi (or other such single-board computers (SBCs))?
Most SD cards have a fairly limited life (as in maximum number of read-write cycles), and in spite of wear-levelling, for relatively frequent disk update applications, would probably fail in a year or ...
1
vote
3answers
239 views
Why are some mp3 players so expensive?
I have noticed that mp3 players around the 32Gb area seem to be fairly expensive; I haven't seen any for less than £150. Conversely, players with smaller storage can be found at a much lower price, ...
4
votes
2answers
457 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 ...
2
votes
0answers
237 views
Moving mass storage design from SD/MMC to NAND flash
We have a prototype design in the works, that is currently running on a reference board done my Olimex (Olinuxino maxi), but eventually we would like to move the storage from microsd to nand flash (or ...
2
votes
1answer
227 views
SD card sector address vs. physical location
I'm curious as to how SD cards map the supplied sectors for read/write to physical locations in the flash memory. Is this the real physical address, or is it just a virtual address that the SD ...
5
votes
1answer
109 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 ...
9
votes
1answer
656 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 ...
5
votes
1answer
1k 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 ...
4
votes
1answer
358 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 ...
-3
votes
1answer
1k views
What is the fastest 32gb micro sd card around? [closed]
I've been looking around but I'm having trouble understanding the class speed system. What is the difference between, for example, Class 10 and UHS Speed Class 1? Are SDXC cards faster than SDHC?
4
votes
3answers
402 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
437 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 ...
8
votes
2answers
1k 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
4
votes
1answer
494 views
MicroSD Card Slot SPI Signals
I am having trouble communicating with an microSD card with an AVR on a board I'm working on. I used an oscilloscope to have a look at the signals coming out of the microSD socket on my board. I saw ...
0
votes
0answers
185 views
MicroSD SPI mode read/write problem after some addresses
I am work with micro SD cards in SPI mode , and met a strange problem . Some microsd cards do not want to read/write after some special addresses.
MicroSD 8GB stop to read/write after block 0x7670 ...
3
votes
2answers
139 views
Is it normal for a micro SD card to have higher write speed for the first blocks?
I'm using a micro SD card of 4Gb from Kingston in an embedded project and I'm accessing it with a low level SPI driver.
Everything is running just fine, except for a weird behavior: after a given ...
1
vote
2answers
609 views
Combining netduino with Ethernet Shield
While buying hardware, the Netduino Plus was not available so I bought Netduino and Ethernet shield. These days I have been trying to create and example of web server using Netduino and Ethernet ...
3
votes
1answer
1k views
SD Card Interface with Pic Mcu - Part_1
I am trying to interface micro SD card with PIC MCU using SPI-mode of SD protocol.
Being a beginner, I tried to get the R1 response from the SD card by sending the command '0' through SPI ie.,
...
4
votes
1answer
488 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 ...
2
votes
1answer
1k views
Memory Card to USB IC?
Today I purchased a USB memory card reader. I cracked it open and saw that it basically only has an AU6477CL IC, which is based on the AU6370, which is a chip which takes SD/MMC/etc pins as input and ...
8
votes
2answers
1k 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 ...
3
votes
4answers
412 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 ...
4
votes
1answer
206 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 ...
3
votes
3answers
563 views
Logomatic v2 serial SD Datalogger issues
Hi i bought this data logger a few weeks ago, http://www.littlebirdelectronics.com/products/Logomatic-v2-Serial-SD-Datalogger.html
I've been having some trouble with it. I read the data sheet and ...
1
vote
3answers
634 views
High-speed RS232 logging
Does anyone have any recommendations on an embedded platform that would be able to handle RS232 at 921600 baud and log it to a microSD card or something similar?
4
votes
6answers
1k views
Micro SD Shield
Got a new MicroSD shield from LittleBird, having some troubles with it,
Downloaded the sample library that it said to used threw in a MicroSD card and expected it to work... It won't initialise for ...
