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Questions tagged [eeprom]

Acronym: Electrically Erasable, Programmable Read-Only Memory. Sometimes used with Flash parts that are similar to old EEPROM parts.

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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?
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2answers
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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 ...
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7answers
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Why is serial EEPROM preferred over parallel EEPROM?

In the wikipedia page for EEPROM: http://en.wikipedia.org/wiki/EEPROM it is given that "Parallel EEPROM devices typically have an 8-bit data bus and an address bus wide enough to cover the complete ...
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8answers
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EEPROM is a “Read Only Memory,” so why can I write to it?

Electrically Erasable Programmable Read-Only Memory (EEPROM): If it's using Read-Only Memory (ROM) then how am I able to write to it?
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4answers
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Wear leveling on a microcontroller's EEPROM

For example: The datasheet for ATtiny2313 (as do most Atmel AVR datasheets) states: 128 Bytes In-System Programmable EEPROM Endurance: 100,000 Write/Erase Cycles Imagine a program only requires ...
14
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4answers
6k views

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 ...
12
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3answers
15k views

I2C minimum clock speed and reliability

Is there a minimum clock rate specified by I2C? I know the most widely used clock rate is 100kHz and there is a "fast" mode of 400kHz supported by some devices, and a faster yet mode supported by ...
11
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8answers
5k views

Saving data without a microcontroller?

Is there a way to save voltage data directly (without a microcontroller) to anywhere, like EEPROM, SDCARD, etc.? For example, I am using an MPX pressure sensor which gives 0V to 5V analog output. ...
11
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7answers
19k views

Erasing EPROMs with sunlight

I have heard (I'm not sure how valid it is) that EPROMs could be erased by exposure to UV light. My professor had mentioned it in my Microprocessor Design class; however, I'm not sure if he's bluffing ...
11
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2answers
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Inbuilt flash memory size not enough

I am using TM4C1230C3PMI controller from Texas instrument in one of my project. It has 32KB of internal flash, which is not sufficient for my application. Higher flash sized micro-controller are ...
11
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2answers
22k views

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 ...
11
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3answers
4k views

What are some typical low cost microcontrollers and chips that are used in electronic toys?

I'm researching microcontrollers, memory chips, and sound chips for simple electronic toys. These toys might take user input via buttons or switches, and then play back sounds stored on a memory chip ...
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3answers
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Why does this EPROM have comb-like structures around the wire bonding pads?

I took some pictures of a Microchip EPROM die from the late 80s / early 90s (I can't recall the exact part number). The wire bonding pads are surrounded by a comb-like structure. What is the purpose ...
11
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2answers
9k views

Program AVR EEPROM directly from C source

When you include the following code in an AVR C source, you can apparently directly program the fuses, without the need for an extra command or .hex file: ...
9
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7answers
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Alternatives to using EEPROM

As I understand it, EEPROM is a part of a computer (in my case, an AVR microcontroller) which stores data, and holds on to it even when the device completely shuts down. It allows data to be written ...
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5answers
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Frequent Write to Non-volatile Memory

I am designing a device that automatically adjusts it's physical position as temperature changes. If the device it shut off or power is disconnected the device needs to remember it's last temperature ...
9
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5answers
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Memory suggestions for MSP430

I'm developing a measurement application with the TI MSP430 and I would like to hear some suggestions on what type of memory I can use. The idea is to use it for logging during a certain time and ...
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5answers
2k views

I2C EEPROM bit-banging: Writes fine, but only if first bit is not set

I am currently working on an I2C EEPROM project using bit-banging to drive the SDA and SCL lines. My read function works fine but whenever I write any byte with a leading "1", I always read FF back; ...
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9answers
1k views

EEPROM with high endurance

I am currently working on one embedded project in which I have one counter which will be active all the time. If the power goes down then also I have to store last counter status and load it back in ...
8
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1answer
3k views

SPI data storage devices: (micro)SD card, DataFlash, or serial EEPROM?

I am revisiting some of my design habits, and one of them is under serious scrutiny: the go-to SPI-based storage device is (micro)SD cards, for their price-to-capacity ratio and generally higher ...
8
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3answers
3k views

EEPROM read/write errors on dsPIC

I'm running a Microchip dsPIC30F6012a. I have this chip on several PCBs, all running the same software, and observe the same problem on all of them. This implies a systemic problem, not a one-off ...
7
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5answers
2k views

EEPROM endurance in energy meter?

I am designing an energy meter for electricity billing purposes by converting an analogue energy meter and counting the number of pulses given by the analogue meter's LED. Since power may be cut off ...
7
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3answers
568 views

Why is there a maximum time for length of write pulse to write on an EEPROM?

I am still just learning about electronics on my own, so please bear with me. The EEPROMs that I have come across (for example this one where the t_wp max is 1000 ns.) all have a time limit for the ...
7
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1answer
2k views

How does memory wear out?

I know that after time due to writing/re-writing memory wears out, and I was reading about a microcontroller from TI which uses "wear leveling" to insure the longest life of some EEPROM that the chip ...
7
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2answers
2k views

Encrypt sensitive data in EEPROM

Let's say I have a PIC and an EEPROM memory IC. I store sensitive data in the EEPROM. If I want to encrypt the data what is a good encryption algorithm? It should be executed by the PIC but that does ...
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2answers
4k views

28C64 EEPROM Programming Using Arduino

I am working on a Z80 computer and needed to write data to an EEPROM. I am using the Xicor 28C64AP-25 chip (datasheet). I wrote a program for the Arduino Uno that writes data to the first 4 addresses ...
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3answers
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100k EEPROM writes “per bit” or as a whole?

As I understand it, the life of an EEPROMs is usually rated at a certain number (e.g. 100k) of writes. Is this "per byte" or writes to the EEPROM system as a whole? E.g. If the EEPROM has 4k bytes, ...
6
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2answers
1k views

How is this EEPROM fully addressable?

I am looking at the datasheet for this 64k EEPROM, and I am having trouble understanding how to use it. I would like to do a lookup from a 16-bit address to an 8-bit data word. The chip only has 13 ...
6
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4answers
1k views

Will an SPI flash memory chip have the same issues with non-atomic write operations as a dsPIC's internal EEPROM?

A while back I had some intermittent trouble with the internal EEPROM of a dsPIC. Every so often, some value in the EEPROM would be found zeroed out on power-on. I tracked the problem down to when the ...
6
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3answers
1k views

Why are EEPROM sizes measured in “k” or kbit and not kbyte or byte?

I keep seeing EEPROM datasheets using terms such as 4k, 16k, etc. and they're referring to 4 kilobit and 16 kilobit, bits, megabits, and kilobits are often used. Very seldom do they use byte prefixes. ...
6
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1answer
511 views

EEPROM: Same driver for similar chips, different behaviours

I have two very similar eeproms (M24C01-x and M24C64-x), both driven by the same standard library provided for my STM32F2. For the M24C64-x, all is fine. However, the M24C01-x is interpreting the ...
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2answers
1k views

Serial EEPROM with FAT

Is it possible to format an SPI EEPROM (such as AT24C128) to be used as an SD card? So format it with FAT 32 and have a 16MB drive appear in windows? Thanks
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3answers
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Why isn't there any EEPROM in STM32F4 MCUs? [closed]

Why isn't there any EEPROM in the STM32F4 series MCUs? Mostly I have Microchip MCUs and they have EEPROM available in them, but I just found out that it is not available in the STM32F4 MCUs... And it ...
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2answers
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Does a microcontroller fetch instructions in blocks?

It seems that the flash memory on most microcontrollers that stores the assembly code is NAND flash, which is only accessible on a per-block basis. Does the CPU has to fetch an entire block to execute ...
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5answers
837 views

Tiny parallel eeprom

Is there such a thing as a low pin-count eeprom IC that can be used to replace logic circuits with just a couple of inputs and outputs? I'm thinking of DIP-16 or smaller, but it needs to be parallel. ...
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3answers
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Minimum voltage to avoid EEPROM corruption for ATMega328P

I have a battery powered contraption with an ATMega328P with Arduino code that sleeps most of the time. Occasionally it needs to write some values to EEPROM. It's battery powered so I have tried to ...
5
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2answers
3k views

What do memory configurations like “256Kx18” mean?

This is a beginner question here. When choosing memory ICs, one of the options is the memory size/configurations. I understand the size part, but what does the "16Kx9" mean? It seems the same memory ...
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3answers
5k views

Flash EEPROM Emulation

Given that there are many differences in the way data is written to EEPROM and Flash, how exactly is EEPROM emulation done with internal flash? Also, flash needs to be erased in large blocks before ...
5
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1answer
487 views

reading EEPROM at startup only versus reading everytime from EEPROM

I have an AVR code where I store data in EEPROM, this data is actually some settings and USER phone numbers. These are quite often accessed. So I planned to read all the values at start-up to memory ...
5
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1answer
7k views

Is there a way to preserve EEPROM contents in AVR Atmega when burning a new firmware to flash with avrdude?

I'm finishing an application which will use some non-volatile parameters stored on an AVR Atmega644P EEPROM. The initial EEPROM values were generated using the EEMEM attribute (like described on this ...
5
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4answers
2k views

Difference between data retention in flash and in EEPROM

In a security recommendation (Mobile Operating System Protection Profile, §4.2.1 FCS_CKM_EXT.4.1), the following instructions are given to securely wipe a cryptographic key from memory: For non-...
5
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1answer
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How to write to 93LC46B EEPROM from an Arduino using SPI

I have a question regarding eeproms and an Arduino (I am using Arduino Uno). I have the following eeprom: 93LC46B. From the datasheet I understand that in order to write the integers ...
5
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1answer
3k views

Replacing 27C256 with 28C256, how to wire /WE?

I am looking to replace a 27C256 compatible maskRom (nintendo Nrom PRG and CHR if it matters) with a socketed 28C256 in order to make a development cart. It looks like the pin for A14 is in the wrong ...
5
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1answer
969 views

Unknown SOT-23-5 I2C device

I have a small board that stores some static and dynamic data: cc 80bytes of serial number, manufacturing date and a counter. The board has two SOT-23-5 components: one is with CBOCX and one is with ...
5
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1answer
244 views

What is wrong with my eeprom?

I am using an eeprom M24C32-W from ST. Here is my schematic with VCC=3.3V. The write protection Write Control pin is connected to VSS and thus should be disabled. The address of the device is 0xA0 (or ...
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2answers
6k views

Interfacing PIC18F4550 with I²C EEPROM (24AA1025)

I am working on a university project in which I need to interface a PIC18F4550 with an I²C EEPROM. I read many codes and saw many projects on this topic. And I wrote a sample code from MPLAB C18 (and ...
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3answers
3k views

Failure mode of FLASH memory

What is the failure mode of flash memory? I've got some chips rated for 10,000 cycles - what happens after 10k cycles? Do the chips stop writing properly, do you get read errors, etc.? Does it also ...
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2answers
3k views

Difference between EEPROM types

I was wondering what the difference between EEPROM types are. For example 24S128 and 24LC128. My understanding is that typically the later digits, 128 in this case, represent the amount of space ...
4
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1answer
848 views

Is 3 bytes a min to address a register in a 256K EEPROM?

I am really new to electronics and embeds and I am struggling with some probably basic notions. (I have a software background.) I have an EEPROM (24LC256) connected to an MBED microcontroller and I ...
4
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3answers
2k views

I2C EEPROM with non-standard address?

So I know that almost all i2c EEPROM ICs use 0xAh (or 1010) as the top four bits of the slave address. I currently have a 16 kbit EEPROM on my i2c bus that uses the lower 3 bits of the slave address ...