Comments on: Parts: SPI EEPROM (25AA/25LC)

By: Ian Lesnet

Ian Lesnet — Thu, 02 Jul 2009 18:06:40 +0000

We used XON/XOFF software flow control with a 'dribble' buffer in the JTAG programmer code.

By: Todd

Todd — Thu, 02 Jul 2009 17:29:54 +0000

@killerspud – You would need to stream the file to your microcontroller, using a receive buffer to hold the incoming data while you write it to the eeprom.

Think of it like a sink. The faucet is the PC sending the file to the microcontroller. The basin is the buffer. The drain would then be the eeprom. If the faucet/PC pours water/data in to the basin/buffer faster than the drain/eeprom takes it out, the basin/buffer will over flow, and some of the water/data wont make it to the drain/eeprom.

Just make the PC send the data slower than the micro can write to the eeprom.

By: Ian Lesnet

Ian Lesnet — Wed, 01 Jul 2009 06:53:11 +0000

@matt – Fantastic idea, we’ll find some BIOS chips to play with.

@gcl – Yup, Maxim makes an I2C->1-wire converter chip, and other adapters. 1-wire, I2C, and other buses are common inside a PC. 1-wire parts are often used for their unique 64bit serial number.

I’m not sure of many places where you can get those signals outside of the PC without some sort of external bus adapter. I know there’s an I2C connection for DDC in DVI connectors and some VGA cards.

@killerspud – EEPROM programming from a file is on our development roadmap. It’s a needed feature. We’ll just recycle the code we used for the JTAG XSVF uploader.

By: KillerSpud

KillerSpud — Wed, 01 Jul 2009 04:32:07 +0000

Are there any provisions for uploading files to EEPROMs? A common reason to use these memory chips is when your uC’s onboard memory can’t handle what you want it to do (I.E. sound or picture files). But then you run into the problem of how to get your files onto that chip, so you have to invest either time or money in a separate device just to burn your memory.

I personally don’t know a thing about common file transfer protocols (xmodem, kermit, etc.) so I don’t know what to do (and I’ve got a pile of other projects to work on).

By: gcl

gcl — Wed, 01 Jul 2009 00:05:00 +0000

Okay, I believe Maxim makes hardware that translates from one protocol to the other.

Incidentally the One-Wire one is actively developed for by Linux users, including myself.

By: Matt

Matt — Tue, 30 Jun 2009 22:27:29 +0000

What about using this with the SPI parts used for BIOS? It could be useful in un-bricking mainboards with a bad flash.

By: Ian Lesnet

Ian Lesnet — Tue, 30 Jun 2009 20:48:58 +0000

The ’3EEPROM’ test board in the picture has a 1-wire EEPROM, I2C EEPROM, and SPI EEPROM. We use it to test these protocol libraries before releasing new firmware.

By: luke

luke — Tue, 30 Jun 2009 19:33:24 +0000

Is there a good site or book out there that can help me start to understand electronics? I have played with them ever since I was a kid and I would like to know more. Where do I begin?

By: Mark barnes

Mark barnes — Tue, 30 Jun 2009 19:10:12 +0000

hackaday have bus pirates on the brain??