Parts: SPI EEPROM (25AA/25LC)

June 30, 2009 by Ian 11 Comments

3EEPROM-SPI

Microchip’s 25AA/25LC EEPROMs are data storage chips with a simple 3-wire interface. The 25AA/LC is an SPI version of the common 24AA/LC I2C EEPROM. It comes in capacities of 128bytes to 128kilobytes. We looked at the smallest, the 128byte 25AA010A.

There are Bus Pirate demonstrations for most types of serial EEPROMs. Check out our previous 1-wire (DS2431) and I2C (24LC1025) EEPROM posts.

Continue below to see our test circuit and a demonstration of the 25AA010 EEPROM. We used the Bus Pirate to play with this chip from our PC. For a limited time you can get your own Bus Pirate, fully assembled and shipped worldwide, for only $30.

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Guitar Hero Macro Board

May 3, 2009 by Eliot 13 Comments

guitarheromacro

Doesn’t look like the Guitar Hero hacks will be slowing up any time soon. In this recent installment, [Thunderhammer3000] built a board to record Guitar Hero “songs”. It is wired inline with with the fret buttons and strum bar and records each of the key presses. Songs can be recorded at slow speed in practice mode and replayed at full speed. The board is Arduino compatible and has two optoisolator chips for collecting the button presses plus a small EEPROM for storage. The board fits easily inside the guitar body.

25C3: Solar-powering Your Gear

December 27, 2008 by Eliot 10 Comments

solar

The 25th Chaos Communication Congress is underway in Berlin. One of the first talks we dropped in on was [script]’s Solar-powering your Geek Gear. While there are quite a few portable solar products on the market, we haven’t seen much in the way of real world experience until now.

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Parts: 1K 1-Wire EEPROM (DS2431)

December 24, 2008 by Ian 26 Comments

1keeprom-450

The Maxim DS2431 1K EEPROM is 1-Wire device that adds storage to a project using a single microcontroller pin. We previously interfaced a 1-wire thermometer, but this EEPROM is slightly different because it draws power directly from the 1-Wire bus. Grab the datasheet (PDF) and follow along while we read and write this simple 1-Wire memory.

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Tripmate Gps Data Logger

January 26, 2007 by Will O'Brien 7 Comments

This one is fitting – I was just checking out Suunto’s sweet gps data logging watches today. [Steve Cholewiak] sent in his diy GPS data logger. It uses an old DeLorme tripmate – these were serial gps units that ran off of internal batteries. A PIC controller reads the NMEA sentences from the tripmate. Then it stores the track data to an EEPROM. The same serial connection is used to retrieve the data later on. [Steve] did a great job writing this up, the circuit is pretty simple and he’s provided all the information you need to build your own.

Five Dollar Eprom Programmer

November 8, 2006 by Will O'Brien 23 Comments

A couple years ago I spent a good week wiring up a fairly complex EPROM programmer so I could burn a prom for my jeeps EFI system. Today I ran across this $5 version. ~~build~~ built by Jay Kominek He uses shift registers to handle the addressing and IO lines, all driven directly by the parallel port. There’s no way to escape the number of pins that have to be wired up, but the schematic itself is pretty simple.
[By the way, arcade supply shops are a great source for cheap UV erase EPROMS.]

[Update: I’d forgotten about the voltage change (3 vs 5 if I remember) needed to write UV EPROMS vs EEPROMS. With a little mod, you can certainly use this for EPROMS as well.]