The Microchip 24LC256 (& associated chips) family have fairly large
capacities & are pretty easy to interface to (2-wire interface);  See
specs down from http://www.microchip.com/0/Lit/Memory/index.htm, for the
larger chips see
http://www.microchip.com/0/Lit/Memory/IC/64to128/index.htm.

  The 24LC256 is a 32k byte (8-bit bytes) i.e. 256k bit part.  64-byte
page mode available.  It's available in DIP-08 or SOIC-08 packaging,
which is nice!  $3ish in quantity.

  For one project, the customer (second alpha tester) feels we need 1/2
megabyte of SEEProm, so we're looking at either that part, 16 in
parallel of 'em, which would take 3 PIC pins;  or alternately at the
Atmel DataFlash parts at
http://www.atmel.com/atmel/products/select15.htm, for the first manual
page of their 512k byte i.e. 4 Megabit part, see
http://www.atmel.com/atmel/postscript/first_page/doc0803a.gif; They go
from 2 megabits, up to 16 megabits on one 2.7V part (!)  Disadvantages I
can see so far over Microchip parts are size (soic-28 vs. -08, also in
TSOP-28 and PLCC-32 packages) and it's a bit harder to use, 2048
264-byte pages, not byte accesses;  advantages are it's fast! (10 MHz
max clock rate), & lots of data in one chip, don't have to run 16
24LC256's for the same storage, and cheaper ($10 for a half megabyte
instead of $50ish for 16, 24LC parts.)

  Atmel has regular Serial EEProms at
http://www.atmel.com/atmel/products/prod6.htm, also.  1k bit up to 256 k
bit, I haven't looked at those much, the Microchip parts may be a smidge
easier to use? but maybe these are more versatile?, don't know pricing
but imagine it's comparable.

  (Personally I still think we could get by with 2 24LC256'es, but, "The
customer's always right."  Ack!)

  Mark Willis, mwillis@nwlink.com

Arvi Karhumaki wrote:
>
> Does anybody know of a way to combine a PIC with a really large chunk of
> serial memory, much more than 8 kilobytes? Do you know what serial memory
> chips are available, and practical? EEPROM or FLASH would do, it's got to be
> non-volatile memory.
>
> Arvi Karhumaki                          EMail:  arvi@vistacom.fi
> Support Technician                      Phone:  +358-9-6226 2325
> Vista Communication Instruments