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 is the difference between Flash memory and EEPROM?

Flash memory storage and EEPROM both use floating gate transistors for storage of data. What differs between the two and why is Flash so much faster?
skyler
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Why would one still use normal EEPROM instead of flash?

Is there any reason why people are still using (and implementing in new systems) normal EEPROMs instead of flash memory, nowadays? From the Flash memory wikipedia: Flash memory was developed from EEPROM (electrically erasable programmable…
user17592
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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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Why do we need a bootloader separate from our application program in microcontrollers?

Why do we need a separate program in the same flash program memory of a microcontroller, specifically STM32F103, which is called a bootloader? What is special about it to keep it separate from the main application program? Generally speaking, does…
alt-rose
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MicroSD card performance deteriorates after long-term read-only usage

I'm using a STM32L432 microcontroller to read data from a microSD card via SPI. In my application, I'm playing a sound file with a length of 10 s in loop. I found out that after the application ran for approximately 20 - 25 hours, the audio stream…
Hermetica
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Is firmware code or data?

When someone says they "flashed" firmware to a device, I'm curious as to what this actually implies. Is firmware just a native binary that is stored in memory and that can be interpreted by the device's CPU (like any other EXE on a computer)? Or is…
HeineyBehinds
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Why does flash memory have a lifespan?

I've read that flash memories can "only" be reprogrammed 100000 to 1000000 times, until the memory storage "deteriorates" Why exactly does this happen with flash and not other memory types, and what does "deteriorate" refer to, internally? EDIT:…
triplebig
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What is dual/quad I/O?

Reading an SPI Flash datasheet, I encountered the concepts of "dual I/O" and "quad I/O". At first I thought that "dual I/O" was synonymous to "full duplex", but then what is "quad I/O"? What is dual I/O and quad I/O, and how do they compare do…
Randomblue
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STM32 & ST-LINK - Cannot connect to MCU after successful programming

I have built my own board with STM32F7-45VGT6. I have successfully programmed it with ST-LINK v2 (not the original one though) and now I cannot even connect with MCU. I use ST-Link Utility from ST and SWD interface. It can be the case that I use SWD…
zupazt3
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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 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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Why do most of the non-volatile memories have logical 1 as the default state?

I have used non volatile memory, like EEPROM and FLASH memory, in embedded applications and I have always found that unused memory (EEPROM/FLASH) bit locations are always set to 1 by default. Why is this used instead of 0? For example an address,…
Rookie91
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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
jpeskin
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Flash and EEPROM

Atmega16 datasheet says that it has a) 16 Kbytes of In-System Self-programmable Flash program memory and b) 512 Bytes EEPROM. Can a microcontoller have two separate ROMs which can be programmed through EEPROM technology and Flash technology? Or Is…
Jasser
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SPI: TI or Motorola mode?

I am programming a Cortex M3 bare-metal to talk with SPI Flash. One of the configuration bits of an SPI control register is FRF (Frame format). It can either be set to SPI Motorola mode (0) or to SPI TI mode (1). (See the ARM reference manual page…
Randomblue
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