-- [ From: Peter L. Taylor * EMC.Ver #2.5.02 ] --


> >Does anyone know if there are any large (> 2KBytes) ram chips that
> >are serial addressable. I've seen that there are quite a few
> >EERAM chips, and quite a few 256 Byte chips.
> >
> >I have a data logging application that needs 8KB -32 KB of RAM.
> >
> >Thanks,
> >
> >Peter.
>
> Digi-Key (www.digikey.com) sells microchip and national serial eeproms
upto 16K
> bits (2K bytes). These devices are listed in the manufactures data books
as
> upto 64K bit versions.  Upto 8 devices can be daisy chained on the same
I/O.
> Best of all they are 8 pin dip or surface mount.
>
> download data specs from microchip.
>
> michael
>

National Semiconductor makes a 4M/8M bit serial flash ram part.  The part
numbers are: NM29A040/080.  The data sheet is one their web page (http://www
.natsemi.com/), or I could e-mail it to anyone interested.  The parts come
in a 28 pin SOIC or PLCC.  Only 6 pins are used;  the die must be really big
.

The only gotchas of this part are: 1)It is National Microwire compatible,
which isn't necessarily Microchip SPI compatible, 2)Before using the part
you have to read the upper block to find any bad blocks that shouldn't be
used.

If anyone figures out how to use the Microchip SSP port, in SPI mode, with
this part, please let me know.  As far as I can figure, the only way to
interface to it is use three port lines, and bypass the SSP module.

Peter Taylor
TransEra Corp.