Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [nand-flash]

64 questions
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Why are NOR flashes still used when NAND flashes have a bigger size?

I've seen a few systems that uses a NOR flash to boot from, and a NAND for a bigger filesystem. I've also seen a system with only NAND gets corrupted after files being written to and verified correct. Are NOR used because it is more liable to boot a…
minghua
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What are the "redundant bytes" added to every page of this NAND flash?

I was tinkering around some NAND flash memories and found out that some of them (not sure if it's all of them) have a few "redundant bytes" that are something of a mystery. (See related questions here and here.) This part is from the TC58NVG0: I'm…
Tirdad Sadri Nejad
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Flash memory data retention time

I'd like to buy one of those after market Android car head/infotainment units. But I don't think there's a way to reinstall the system software if it gets corrupted, so I'm concerned about how long the data will last on the Flash memory. I've found…
Yale Zhang
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eMMC vc MMC storage

I came across this new technology for storage and I am still a bit confused. What are the basic differences between MMC and eMMC storage? If a microcontroller is marketed as supporting SD/MMC, can I consider them as compatible with eMMC as…
JG_Bozza
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Why is NOR memory considered XIP, and NAND memory is not?

I've been reading up on NOR and NAND memories in search of an answer as to why exactly is NOR a XIP (eXecute In Place), and NAND is not. While both of the links were extremely informative and well-written, neither explicitly satisfied my…
ReoTheYokel
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Does cooling the NAND chips on an SSD negatively affect its reliability?

The problem of heat dissipation in high-performance, small form-factor SSDs is well-known, for example, the paper Transient Thermal Analysis for M.2 SSD Thermal Throttling published in 2018 17th IEEE Intersociety Conference on Thermal and…
比尔盖子
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Why can't NAND flash memory be a random access memory?

When I read any documents regarding NAND and NOR flashes. They say that NAND is sequential memory whereas NOR is random. I dont understand what stops NAND memory from being random too as the only difference in these two memories are being serial and…
JIN007
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Is it possible to read erased flash memory?

In hard disks, a "quick format" does nothing to the actual data on the disk - just clears the FAT (file allocation table), which then appears as a "blank disk" to the user. Therefore, it is fairly easy to ignore the FAT and read that data. Although…
rdtsc
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eMMC interface : Parallel vs SDIO

I want to use an eMMC card for my application. After searching on different websites,I was not able to find any parallel interface supported eMMC chip. Is parallel interface available for eMMC chip? What are main differences of eMMC parallel vs…
kernel
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What are two typical threshold voltages for a flash FET?

I have a simple question for you all: what is a realistic approximation of a pair of threshold voltages for a flash transistor? I am working with NAND flash, 45nm, with VDD = 0.8V. I can find lots of information on the basics of flash, and…
KYLE
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Booting from NOR or booting from NAND

We're working on a new project, and we're considering using a TMS320C6657 DSP, or a similar DSP. There are many boot modes, NAND Flash, NOR Flash, Ethernet, etc. What are the pros and cons of booting from NAND vs NOR ? As far as I know, NOR Flash…
Ben
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Desoldering CPU from PCB or holding it in reset

I am currently working with a NAND flash that I want to dump. The goal is to take a look at the data that is stored in the filesystem. To do so I soldered 8 wires to the NAND flash to access it while it was still placed on the PCB. To read out the…
Ramazuri
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File system to use with NAND Flash and 32 bit microcontroller

I am searching for a file system, suitable for NAND flash memory chips. Currently I use a Micron 256MB SPI NAND flash memory where I write and read raw sensors data but without a file system and error correction. So I decided to move to a file…
Sparky
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How does NAND reading work?

I'm trying to understand how reading from NAND flash works. I know that: when NAND flash is read, the gate voltage goes up to 5 V, then electrons flow depending on holes, then we can read the current. But I can't understand this exactly. Would you…
ele_911
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How does triple level cell FLASH memory achieve 3 bits per cell?

Originally each cell of FLASH memory held either a high or low level or state, and reflected one bit of information; 0 or 1. Mutli-level FLASH was then developed, with often four levels of voltage possible for each cell. These four voltage levels…
uhoh
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