Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [flash]

Flash is a type of EEPROM which is page-eraseable. It's commonly used for microcontroller program memory and code storage. You can use this tag for questions about this type of memory as well as questions about "flashing", the process of changing the data in Flash when programming a microcontroller.

From Wikipedia: Flash memory

NAND vs. NOR Flash memory technology overview Application note by Toshiba

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What are the differences between NAND and NOR flash?

What are the differences and where would you use each?
JeffV
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Flash memory: Does the entire page need to be erased before writing just a few bytes?

An easy question, I hope! I'm not finding any definitive answers... I'm writing drivers for a SST25VF064C flash memory chip. It communicates via SPI. Like all flash memory (that I know of), it needs to be erased (all bits = 1) before it can be…
bitsmack
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Why does NAND erase only at block-level and not page level?

Below is my understanding of how NAND flash memory is organized, with this design it should be possible to just erase a single page and program it instead of erasing an entire block. My question is, why don't NAND implementation erase at a more…
Joel Fernandes
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How does erasing a NAND-Flash memory work?

I am trying to understand how the NAND-Flash memory works and I think I understand how programming a page works but I don't see why inverting all the voltage would not lead to erasing the page. So, why is it that the whole block has to be erased…
mike
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How does NAND FLASH cells retain data without requirement for external power?

RAM cells need constant refreshing, however NAND FLASH cells can retain data for years together. What makes this possible ?
Abhijit K Rao
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Is eMMC really a good choice for a low-volume long-product-life design?

We're looking for a flash device for a low-volume (batches size < 100) industrial product, in the 2/4/8 GByte range. In applications like this we've previously used SD card, which is an obvious choice. For better mechanical robustness and device…
user1844
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Writing a Function at specific memory location of Flash

I want a function to go at specific memory location of Flash and I am not able to figure it out. Do I need to do modification in Linker File? Also, I have idea that in GCC, I would use #pragma directives by which I can put my code in specific…
Swanand
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Flash memory corruption due to electricals?

I'm a software developer working on an in-vehicle (WinCE) device that uses an SDIO card for its storage. We are suffering from (seemingly) random corruptions of the data, seemingly from the FAT table getting corrupted. You may find inaccessible…
Nik
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Is flash chip capacity really limited to the powers of 2?

I have never seen any flash chips with capacity not confined to the strict (i.e. not like in hard drives) power of 2. I wonder what prevents manufacturers from creating such chips: is it some engineering reason, or just the marketing, or anything…
Catherine
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Is it possible to rewrite a Flash page after an interrupted write?

Suppose you have a Flash chip (NOR flash) which you are using for example for data logging, performing sequential writes regularly on it. The question is what if the power goes off during a page write: Is it possible to "fix" the page by rewriting…
Jubatian
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what is the application of "one time programmable" bytes in my flash memory?

My flash memory device A25L032 has 64 one time programmable bytes. It also has software and hardware protection modes for blocks, sectors as well as the whole chip. What application do one time programmable bits have since flash is nonvolatile…
quantum231
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What would happen in case of power outage during NOR flash erase or programming

I am using a SPI-connected NOR flash (AT25DF321a) to protect data against loss during power failure. But how is flash protected against power loss? What would happen if the power turned off during erase or programming? Is it possible to detect such…
edo1
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Can flash memory in smart phones be recovered after being under 10000 ft of ocean water?

If you've been watching the news, you know why I'm asking this. For reasons not yet known, flight 370 from Kuala Lampur left its planned flight path to Beijing, and flew for hours before (probably) crashing in the southern Indian Ocean. If the…
Rob N
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Why do we need block, sector, "all" protect bits in flash device?

I am reading the datasheet for the A25L032 "32Mbit I/O Serial Flash Memory". The page 15 of this datasheet explains that there are non-volatile bits in the status register that can be used to "write protect" a section of the flash memory. Flash…
quantum231
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NAND flash page layout

I'm a beginner. I was going through the Nand flash memory layout. It is given that, page layout can be, Data area & Spare area alternatively. Data area in the beginning & spare area at the end. I'd like to know why the latter is preferred in most…
Gomu
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