Thanks Spehro, (and George too) for the suggestions.
I really didn't want to use serial memory as the processor
is very busy doing stuff and I can only spare a few
instructions to read or write a whole byte. I think I
have found a solution with a nifty circular buffer
using the PICs internal ram, so I may not need the
external memory after all. I think almost any product
can be made with one PIC and one transistor... ;o)
-Roman


Spehro Pefhany wrote:
>
> At 10:44 PM 7/5/02 +1000, you wrote:
> >I'm working on an idea for a robot navigation
> >system using a PIC, but I need approx 2000 bytes
> >or RAM. The ram only needs to be written/read
> >sequentially,

> How about using an SPI addressed FRAM? You'll get
> really fast access and the newer ones have quite long
> read/write life (but work it out). SPI access with
> sequential read is *very* fast, limited mostly
> by the maximum clock on the SPI port. Some can work
> at 20MHz.
>
> Here is one:
> http://www.ramtron.com/products/datasheets/FM25C160datasheet.pdf
> (5 MHz 2K bytes, 10^10 read/writes life)
>
> This 8K x 8 one has unlimited read/writes and operates at 20MHz,
> but only at 3V power:
> http://www.ramtron.com/products/datasheets/FM25CL64ds_r0.3.pdf

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