SEEPROM Amtel AT24C512B

moxhamj

New Member
I'm sure it can be.

I'm interested in this one http://www.futurlec.com/Memory/AT45DB041D-SU.shtml

Only $1.40 and 512 kilobytes of flash ram. Does need a 3V supply though. 3 lines. 2 to drive (they can handle 5V). One to read (which would need a 3 to 5V converter, though you could picaxe that with a readadc and not need the converter). I've got some in the shed but haven't tested them yet.
 

hippy

Ex-Staff (retired)
The AT24C512B is simply I2C Eeprom (64Kx8) and should be drop-in replacement for any other Eeprom. There are also larger devices but check requirements of the A2, A1 and A0 lines and check operating voltages.

The AT45DB041D looks usable with the PICAXE ( the 3V3 ouputs should be compatible with PICAXE Digital Inputs ) but will be more complicated to control and the paged nature may not make that useful for random access ( less than a page at a time ) writing.

I'd recommend using I2C Eeprom in most cases because I2C is so well documented and easy to use, with the PICAXE having the necessary commands built-in.
 

MFB

Senior Member
When the topic of interfacing Atmel Dataflash to the PICAXE was raised some months ago, I posted the following link to a detailed description of how to achieve this with the Parallax BS2. www.emesystems.com/BS2flash.htm

These are SPI devices, which is not a problem for the BS2. However, from what I remember, people seem to be having problems trying to use the new X1 hardware SPI feature at around this time and no one took up the challenge of interfacing Dataflash to the PICAXE.

Time for me to bang on again about REV-ED missing a marketing opportunity, by producing an application note that would make the PICAXE a serious choice for data logging applications. I know that the apologists will say there are limited resources but this could be overcome by forming strategic alliances. In the same way that Parallax have done with educational establishments (eg. StampPlot).
 

westaust55

Moderator
Anyone used one of these, looks quite interesting to expand memory/logging capacity

SEEPROM (Serial Electrically Erasable Programmable ROM) and connect it to PICAxe with only 2 lines.

http://www.atmel.com/dyn/resources/prod_documents/doc5297.pdf
As hippy says an i2c EEPROM.
The AT24C512B is compatible with the microchip 24LC/512 and 24FC512
http://ww1.microchip.com/downloads/en/DeviceDoc/21754J.pdf
down to the memory arangement and 128 byte page structure and page write buffer.
 

hippy

Ex-Staff (retired)
Time for me to bang on again about REV-ED missing a marketing opportunity, by producing an application note that would make the PICAXE a serious choice for data logging applications. I know that the apologists will say there are limited resources but this could be overcome by forming strategic alliances.
I guess I'd come under the classification of apologist although I'd say it was less about fanatically defending Rev-Ed's position or decisions than explaining why that may be as it is.

Firstly, I agree Rev-Ed are missing a marketing opportunity and I can point to many such missed opportunities. My first contact with Rev-Ed was because I felt there was a major opportunity to be had in opening themselves up to hobbyists though I am not going to claim to have single-handedly brought the PICAXE to a wider audience and I really don't know what their plans were at that time or how I influenced them. Like everyone with an opinion on PICAXE I can see opportunities which Rev-Ed have not taken, and like everyone else who sees a brilliant opportunity that isn't taken it is to me regrettable.

On the other hand, Rev-Ed are in control of their own destiny and it's a matter for them to decide which direction to go in, what is most profitable and makes most business sense, short term and long term. What I or others see as a missed opportunity may be that by definition but all companies ( even individuals ) have to judge whether it is a worthwhile opportunity to take or not. They need the business case for what they do. A genuinely missed opportunity is one which could be taken, is possible to be taken, would be more beneficial than some other choice, and would make sense to pursue.

Key to influencing Rev-Ed is producing a business case, a simple "you are missing an opportunity" or suggesting a means to deliver something, is not always enough in itself. Such a business case must also address arguments against as well as for the opportunity.

We may all in fact be missing an opportunity; and that is in filling in the gaps where we think Rev-Ed are lacking rather than just asking they be filled.
 

Mycroft2152

Senior Member
I guess I'd come under the classification of apologist although I'd say it was less about fanatically defending Rev-Ed's position or decisions than explaining why that may be as it is.
.
Hippy,

I wouldn't classify your comments as apologetic but rather an explanation of "the facts of life" in the business world.

One company's missed opportunity is another company's phonomenally successful next product.

Myc
 

westaust55

Moderator
An interesting article Manuka (Stan).

Serial EEPROM has been around for a while as indicated and even Rev Ed's PICAXE boards such as the AXE022, AXE110 and AXE111 have sockets to take i2c type serial EEPROMS.
 

MFB

Senior Member
Serial EEPROM are certainly the way to go if you only need 128Kbytes per package and I am currently using four Microchip 24FC1025 to obtain a total of 512Kbytes on a single I2C bus. However, if you need more EEPROM storage you have to add some form of bus multiplexing and more IC packages.

The potential advantage of the Dataflash devices is that you can store up to 8Mbytes of data in a single 8-pin package costing only a few GBP (which compares very favourably with the size and cost of an SD card interface, for example). A combination of surface mount 40X1 and Dataflash chip could result in a pretty compact and low power data logger.

All we need now is a smart person to show the rest of us how to interface the PICAXE hardware SPI bus to Dataflash!
 
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