re: [oc] EEPROM Programmers using FPGAs? now its EPROM vsFLASH ti me

["Zhichong Chen (Beijing)" <ZhichongChen@viatech.com.cn>]

hi,Dani:

you are right. In order to preventing frequent erasing the FLASH block or
total FLASH chip we can
use SRAM as write-cache which will effectivelly extend the lifetime of
FLASH.
However, the access times limitation must be remembered.

chen.

===
Am Dienstag, 8. Januar 2002 13.25 schrieben Sie:
> It's very easy to use FLASH.
> Martin has explained the speed of FLASH,but the one thing should be
> carefully treated using FLASH, which is
> it's life time.As you know FLASH has write access times limitation, when a
> position in FLASH have been rewriten
> up to 100,000 times it will be crashed that means you will lost your data
> which stored in this position.So you need
> schedule the writing access very soomthly to extend the total FLASH RAM
> lifetime.
>
;-) Well if Paul would erase his eprom for 20 minutes each time. We has 4 
years of work ;-)
There are also other types that last longer, but your right, we want to use 
jffs and we write tiny logs all the time. With such a setting the number of 
erase cycles of the chip is limited to 100'000 times. It is not that you can

only write 100'000 times at the chip. You can write 1's down to 0's and if 
you filled up the chip, then you have to erase it again. That number of 
cycles is limited to 100'000.

Dani

> sincerely
> chen
>
> Hi Paul,
> <snip>
>
> >How easy is it to use FLASH? As easy as SRAM? What sort of access speeds
> >do you get from them? And how much do typical units cost?
>
> It's as easy to read as SRAM, 80-120ns access times are typical.  Writing
> is accomplished by sending (writing) a series of commands and data to the
> device, for erasing pages of memory and then writing the data values and
> write protecting and so-on.  AMD have good datasheets on their devices.
> Dunno about prices, I tend to scrounge samples most of the time at the
> moment :-)
>
> Cheers,
> Martin
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