Lpc2000

Thanks for all the suggestions, a little bit more information might 
help after reading some of the posts.

I am reading in an 8-bit int into an array (10000 ints long) and I 
was wanting to update the array one entry at a time as I went along. 
Anyway I can see this is not going to work due to the previous 
comments.

Therefore external memory seems to be the way to go. I would prefer 
non-powered memory as my project is already running off two power 
supplies, 3.3V, 5V.
I only need to write this one array, or parts of, to the memory. Its 
the only part of the program I am interested in keeping. Then I need 
the program to be able to referance that array. Either read each 
individual entry or just read the entire array into RAM when 
requested whichever the most appropriate.
As for the different types of external memory and how you use them I 
have no idea about the different types and the use of I2C and SPI. 
Never used these functions or external memory for any microp.

This is for my final year project at university and I have only been 
using this board for a few months and only on this project. All my 
previous experiance has been with 8051/2s.

I will search for information on the different type of external 
memory, FRAM seems like it could be the best.

Any extra information would be very helpful.

Thanks,

FG

--- In lpc2000@yahoogroups.com, Robert Adsett <subscriptions@a...> 
wrote:
> At 08:42 PM 11/23/04 +0000, you wrote:
> >I take 10000 readings a seconds... therefore writing time for each
> >int has to be <0.1ms, hopefully <0.05ms.
> 
> Well flash won't do it, too slow and as Gus pointed out it wears 
out too 
> quickly.
> 
> A couple of options
> 
> - Don't store everything, either detect power down and just save 
then or 
> save periodically at a slower rate.
> - Use an external non-volatile memory.  Three I can think of that 
might 
> meet you speed and endurance requirements
>      + eeprom backed SRAM (Xicor I think), Acts as sram until 
power down 
> and then writes the RAM contents to ee
>      + battery backed SRAM (A number of suppliers of integrated 
(tophat) 
> and support chips)
>      + FRAM (Ramtron)
> 
> That all assumes you are doing this continually.  The original 
post implies 
> that but it's not entirely clear.  If this is some sort of 
calibration 
> setup then the obvious thing to do is collect the data and store 
it as 
> separate steps.
> 
> The real keys to this is how often do you need to do it and how 
much are 
> you storing, not how long does it take.  The how long feeds into 
other, 
> more subtle, considerations like how long must you have power 
after it has 
> been switched off.
> 
> Robert
> 
> " 'Freedom' has no meaning of itself.  There are always 
restrictions,
> be they legal, genetic, or physical.  If you don't believe me, try 
to
> chew a radio signal. "
> 
>                          Kelvin Throop, III