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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382 views

Issue replacing 27C256 ROM with 62256 RAM

I'm trying to replace a 27c256 ROM with a 62256 RAM, to be able to easily change the memory content. I thought this would be pretty straight forward. Not quite, it seems. I made an simple ...
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EEPROM Reading/Writing without Use of Programmer

I am designing a small password based door lock project which is fully made from logic gates and ICs without the use of any sort of programmable devices(it is a simple university project for the Logic ...
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559 views

EEPROM I2C driver hanged during ESD test?

In our prototype , we have a I2C based EEPROM . During ESD Test(High potential spark is injected into system for a very short moment), the drivers hangs in the I2C code. Basically there are while ...
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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 ...
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779 views

Writing 3 bytes data in EEPROM

In pic18f45k80, the datasheet says one can read and write a byte (8bit) data in EEPROM. I need to write 3 bytes data at once and read it back at once because that 3 bytes data consists of two ...
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590 views

When should I write to EEPROM?

I built a simple project using an arduino to control a I2C digital potentiometer being controlled by a remote control via a IR Detector. The purpose is to be able to control the input signal of a ...
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5answers
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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 ...
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3answers
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Looking for 4 bit memory option

I'm building a small and simple 4-bit CPU and I'm looking for an IC to store the program opcodes. I've considered using eeproms although they seem too large for my purpose, being in the kilobyte ...
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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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Casting integer to character

I am using PIC18f microcontroller. I have to write a 16 bit integer variables (2 bytes) which was cast into two character variable i.e to write each byte in a consecutive adrressess of EEPROM. By ...
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PIC microcontroller and different EEPROM sizes?

What is the significance of how big the EEPROM is for a microcontroller. I'm trying to select another PIC (first one I chose - PIC16LF1827 - didn't have enough RAM for the application I needed it for) ...
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1answer
973 views

27512 pinout and PCB layout

I'm trying to design PCB traces for a 27512 EPROM chip. But its pinout for the higher half of the address bus seems completely illogical to me and I cannot imagine how should I lay out my traces for ...
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279 views

EEPROM Write Limit [duplicate]

Just curious as to why do non volatile memories like EEPROM in an AVR have a write limit ? Also is this limit per location/adress in the memory or on the memory as a whole ?
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151 views

EEPROM address definitions and delay

I am using 24LC256 EEPROM which have addresses from 0x0000-0x7fff. But I would like to predefine certain address from EEPROM to specific tasks, like from 0-100 for task-1 and so on. Does predefining ...
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1k views

usb drive EEPROM IC how is memory read-only blocked and unblocked?

I notice ofteen free give-away usb thumb drive come with a certain memory space locked and unwritable so that a 4 GB flash drive for instance has 1GB of advert which cannot be format. Given that thumb ...
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587 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 ...
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Program a 27c512 eeprom?

I have a W27C512 chip in my sights. This will be my first time using a programmable rom. I need to know how to convert any form of human-readable code into either HEX or BIN format. Here are the ...
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624 views

Programming an EPROM using 8085 kit

I need to program an EPROM/EEPROM with the code for an 8085. I do not have a programmer. I can't buy one. But I have access to an 8085 kit. Can I use it to program the EPROM/EEPROM via an interface? ...
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657 views

Play PCM stored in EEPROM without microcontroller

Is it possible to connect digital-to-audio converter with a EEPROM storing PCM data to play that data with a speaker? I am interested in a solution that does not employ any kind of microcontroller. ...
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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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2k views

eeprom data corruption during power failure

I recently found a problem with eeprom of a PIC16F877A which is used to control the speed of a dc motor. The drive is supposed to work on the last set speed even if the power fails. But the problem is ...
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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 ...
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514 views

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

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 ...
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1answer
86 views

Floating EEPROM (28c64A) pins an option?

I am building an eeprom programmer for the 28C64A (dip package) with my old basic stamp ii "homework" board (lost my arduino in the move). I have the first four address and data pins, as well as W E ...
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381 views

Working principle of floating gate tunneling oxide

Floating gate tunneling oxide (FLOTOX) is used in electrically alterable rom. Tunneling of charge takes place through tunneling oxide into the floating gate. What is the working principle of this? How ...
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1answer
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How to store array of values in EEPROM of ATmega16 and then read it in sequence

I have this program in which I can store a single value in EEPROM. Can I store an array of values in EEPROM? How? ...
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Decoding ADC pin labels

I'm about to buy a parallel ADC to connect to an EPROM in a analog-digital circuit. I've found some potential ADCs but am having trouble deciding if the ADC and EPROM are compatible. A bistable ...
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2answers
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Estimating EEPROM read time

This is a question in relation to USB transmissions crash my software GUI. I posted this question separately so that I could clarify my question separate from the other one. I have the same ...
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3answers
6k views

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 ...
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1answer
459 views

Dot Matrix IC message board [closed]

I'm trying to make a dot matrix message board -type thing work, The dot matrix IC's are the DL-57 Alpha Numeric Dot Matrix Display [Data Sheet] : https://drive.google.com/file/d/...
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1answer
8k 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 ...
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481 views

Algorithm for finding next data in eeprom [closed]

I have an EEPROM and I'm storing data in it, from address 0x00 to 0xff. I have to scan the EEPROM regularly for non zero values. ...
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1answer
827 views

How to effectively tackle long page write in EEPROM

I'm using C18 compiler and 24LC256 EEPROM. I would like to know how to handle Rollover case in terms of large EEPROM write.I'm writing a Routine that writes 120 Bytes every half an hour and i would ...
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Conditions for page write in EEPROM

I have learned about page write operations from App notes and data sheets of EEPROM chips.But i want to clear certain doubts. I have an EEPROM chip which got 32KB and 64B Page Size. 1.Can i Write ...
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1answer
127 views

Microchip, memory measured in IEC?

It doesn't say on the data-sheet, but I'm curious where i can find if Microchip uses IEC or SI as standard for there memory sizes. For example: http://ww1.microchip.com/downloads/en/DeviceDoc/...
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Advice on suitable SRAM

I'm kind of new to all this and the choices out there is kind of overwhelming when it comes to selecting a SRAM package and Flash eprom to go with a 10 Mhz Z80180. I'm looking for a 128 KB SRAM and a ...
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Memory Problems

I've been having some problems with memory ICs, specifically Flash and EEPROM. I've had some experience with the 7400 series for some time...logic gates are pretty straightforward. Input something, ...
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1answer
8k views

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 ...
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1answer
576 views

I2C delay needed and c18

I am using I2C and I have earlier posted doubts about I2C here. I am using PIC controllers and using their compiler C18. I used their libraries to build a function to write data in EEPROM via I2C, and ...
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5k views

CRC for eeprom data check

I wanted to check redundancy in eeprom and crosscheck the data for any errors occurred or not and I ended up reading CRC code. I found it useful but have some doubts that need clarity. My objective ...
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EEPROM data check

I am communicating with an EEPROM chip with micro controller. I am writing certain data in to specific addresses in EEPROM and needs to check the data occasionally. But I have no idea other than ...
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1answer
2k views

Writing data on EEPROM or Flash memory of the PIC18F47J53

So I am using the 18F47J53 in Hitech PICC18-PRO compiler with MPLAB-X IDE, and for some reason there happens to be absolutely no support for the reading/writing function to either the flash or the ...
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402 views

25AA320A EEPROM byte write and page write

I need to write data into my external EEPROM 25AA320A using Attiny2313. I know how to write one byte at a time. For example, spieeprom_write (200, 7); with 200 being the starting address on EEPROM, ...
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487 views

Programming an 82S23

I have to program an 82S23. There is surprisingly little documentation on how to do this. There are datasheets that will tell you how to read it, but not burn. I built one following these ...
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1answer
563 views

How do I determine what microcontroller is the right one for my project? [closed]

I have just started developing a tiny GPS trackingdevice that (eventually) will be able to log positioning-data on demand - via SMS commands and/or via a smartphone-application. The device should be ...
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458 views

PIC : EEPROM not write properly to 0xFF in PIC18F67K22 controller

I am writing values from 0x50 to 0x3ff in EEPROM of pic18f67k22. Whenever eeprom is getting full, I am writing 0xFF and then after write my data from 0x50 location. but some time eeprom is not write ...
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Can I replace an AT28c17 with a CAT28c65B without changing my software?

The AT28c17 is a 16k e2prom while the CAT28c65B is 64K bit e2prom and both are in a 32 pin PLLC package. They have 10 adresss lines with the only difference being the AT28c17 has A0-A10 adress lines ...
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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-...
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289 views

USB device with a serial number and 3 LEDs

I'm looking for a way to build a USB key. I have a bit of experience with the Arduino, however for this project that seems to be a bit of overkill. The key should contain a unique serial number (...
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1answer
3k views

Problem with I2C EEPROM communication

I have a STM32L MCU connected to M24LR64E, an I2C EEPROM. Previously i had this setup working but then i changed some things (layout, firmware) and somehow i screwed the I2C and it is not working now. ...

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