[TI-H] Re: TiDrive (Was PIXpander & Stuff)


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[TI-H] Re: TiDrive (Was PIXpander & Stuff)




I just want to clarify that my EEPROM expander is complete. And contrary
to what Krevinek said below, EEPROM 's are non-volatile (they do hold
their data without power), thus ELECTRICALLY ERASABLE Programmable Read
Only Memory; and they hold their data for up to 10 years (40 years with
the ATMEL EEPROM's I use) or more according to manufacturers. The factor
that determines the EEPROM's longevity in a particular application is
the number of erase/write cycles, and again according to manufacturers
this is anywhere from 10000 to 1 million! (depending on temp, etc.),
more than enough for this application (it would last a few years at
least). And in relation to being modular, an 8 pin IC on a small PCB is
a lot smaller to carry around than a PSX Memory card (although who cares
... really).

Although, I agree that the pixpander would be great for those of you
that own a Playstation. As you might have guessed, I don't, and the main
aim of my project was to investigate a cheap (EEPROM << PSX Memory card;
in Australia anyway) alternative.

Thanx for the constructive input, I may just find some time to finish
some of my projects now.




-----Original Message-----
From: ti-hardware-bounce@lists.ticalc.org
[mailto:ti-hardware-bounce@lists.ticalc.org] On Behalf Of Krevinek
Sent: Monday, 29 April 2002 12:41 PM
To: ti-hardware@lists.ticalc.org
Subject: [TI-H] Re: TiDrive (Was PIXpander & Stuff)



On Saturday, April 27, 2002, at 07:07 PM, Tim Comport wrote:

>
> If anybody is interested, I have a working expander which utilizes any
2
> pin (data and clock) serial eeprom. Although I am currently using a
> BASIC Stamp 2 (which is rather expensive for such a project), I am
> currently learning assembly for the PIC so I can use one of these
> instead. I will soon post my plans on my website at
> http://members.lycos.co.uk/thetechplace (early details are already
> there)

Woo, YAEE (Yet Another EEPROM Expander).

This is good news, as current development is always welcome. When you 
get to the assembly stage, I am willing to help out with a protocol spec

for dealing with the memory chip in blocks so that a TI-based object 
manager can utilize a basic filesystem on the expander, as well as other

expanders using the same protocol.

One of the reasons why the interest around the PSX Expander came about 
is that it is modular, and unlike an EEPROM, you have a supposedly 
unlimited number of writes on SRAM-based memory cards (They don't need 
power to keep data, but it does degrade over a period of about 3+ months

IIRC). Plus with the ability to store things on multiple cards and 
multipage cards, I can easily carry around a couple MBs of data for any 
calc in my pocket.

Still, good luck on your project, since it might offer an alternative 
for someone not wanting an Expander2, but not wanting a PSX-based 
expander either.










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