Super simple eeprom - Page 1
Forum section: electronics / beginners

author: antenna
author_rank: Frequent Contributor
timestamp: March 09, 2024, 09:59:00 pm
content: I need a very simple memory chip that doesn't use addressing or header stuff, basically a 512 to 1024 bit (or more is ok, I can leave it blank) shift register with non-volatile memory that can be programmed once and repeat the same output stream each time it is triggered. I can give it a clock and trigger, but I just want it to repeat a very specific serial logic sequence each trigger pulse or power cycle. Any suggestions?Thanks!Edit: It needs to be tiny and low power, so arduino type solutions are out.

author: wraper
author_rank: Unknown
timestamp: March 09, 2024, 10:10:55 pm
content: Just use a cheapest MCU.

author: WattsThat
author_rank: Frequent Contributor
timestamp: March 10, 2024, 12:44:42 am
content: A bare ATtiny-10 is $0.44 and consumes 200ua in active mode. 1.8 to 5.5v supply. That’s not usable?

author: antenna
author_rank: Frequent Contributor
timestamp: March 10, 2024, 02:20:43 am
content: I didn't realize they came that small, that will work! Thanks! I was tempted to pull an audio chip out of one of the dog buttons and trying to make that work but this neat little micro should work too.Thanks!

author: bingo600
author_rank: Super Contributor
timestamp: March 11, 2024, 05:38:17 pm
content: This might come in handy for tiny-10 programminghttps://junkplusarduino.blogspot.com/p/attiny10-resources.htmlhttps://make.kosakalab.com/make/electronic-work/arduino_tpi_en/https://kevincuzner.com/2020/11/08/avr-tpi-programming-with-usbasp-for-dummies/https://www.buildcircuit.com/usbasp-firmware-update-guide/

author: AndyBeez
author_rank: Frequent Contributor
timestamp: March 11, 2024, 08:09:52 pm
content: Might not be a fit for your application, but be aware of a family of 3 pin serial EEPROMs which are deployed for configuration and identification. Usually termed 1-wire EEPROMs. For example a 1K device in a transistor TO92 package. Maxim DS2431https://www.enrgtech.co.uk/product/eeprom/ET18612841/DS2431-

author: antenna
author_rank: Frequent Contributor
timestamp: March 12, 2024, 12:47:36 am
content: Quote from: AndyBeez on March 11, 2024, 08:09:52 pmI saw those, but not sure about the header data or if they automatically output the contents directly on power up. One of the reasons for this is for transmitter identification. I figured if I had a 10Hz clock oscillator I could program in a call sign as binary and use the output of the chip for OOKing a TX, so that is one of the reasons I didn't want it to need addressing or startup data. I was hoping to run this on a 3v button cell and have it last a while, but if I need to have a micro to tell the eeprom what to output, then I may as well have the micro do it. I was just hoping for a simpler, program once, solution. I get everyones desire to connect a laptop and upload code, it is easy, but even that is far too much for the simple tasks I require it to do.

author: antenna
author_rank: Frequent Contributor
timestamp: March 12, 2024, 12:53:07 am
content: The ideal chip would have a clock pin, a write enable pin, a serial in/out pin, and power pins. If the write enable is high, it accepts data, if not, it simply outputs the programmed string every time it receives power (or a trigger on another pin). No header, no address stuff, just the string in memory.

author: Andy Chee
author_rank: Super Contributor
timestamp: March 12, 2024, 02:02:22 am
content: I would think even an ancient 12F675 microcontroller is capable of your application. It has a 128-byte data EEPROM for storing your string. It has an internal oscillator for running the processor. It has a handful of I/O pins for you to program as input triggers/enables and data output.The microprocessor code is simple; when it detects a pin going high, it dumps the EEPROM contents out another pin! And you could probably include a RS232 interface to re-program the EEPROM contents on-the-fly.There are certainly more capable microcontrollers that would fit the bill.

author: Andree Henkel
author_rank: Regular Contributor
timestamp: March 12, 2024, 09:13:20 am
content: The most easy to interface in firmware is SPInumber of pins of interface to µController1: single wire -> 2: I2C -> 3: SPIdifficulty of firmwareSPI -> I2C -> singlewire

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: March 16, 2024, 12:35:31 pm
content: Signetics made something in the 70s very similar to what you are asking about. It is a simple one bit shift register with up 1024 bit storage locations. Clock in the bit stream and continue clocking to recirculate endlessly. I have a couple that are 256 bit x 2 for a total of 512 bit storage. The downside is that they are volatile memory. If you can keep a power source on them they might work for you. The part number I have is. Signetics 2527V in 8-pin DIP. The 2533V is 1024 bit.