Tagged Questions

1
vote
0answers
65 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 ...
2
votes
1answer
241 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 ...
4
votes
1answer
383 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
461 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
3
votes
2answers
140 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 ...
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 ...