Microchip has an application note on attaching SRAM to a PIC16CXX (TB011).
This application note shows a circuit in which 2x256K(32Kx8) chips are
hooked up using a 16-bit address bus multiplexed with an 8-bit data bus
(total of 19 pins).

There is also an application note on connecting external memory to a
PIC17xxx via it's inbuilt bus (TB005).

The opnly limitation is the size of address bus you can manage. Obviously
you can get a very large bus with lots of multiplexing but this adds
components and complexity (both to circuit and to code). I'm also not sure
about whether timing would become an issue with more chips.

However, it is certainly possible to hook up at least 256K to almost any PIC
with an efficient use of pins.

Hope that helps,
Tom.
----- Original Message -----
From: Brian Gracia <bgracia@RTRIPP.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, July 22, 1999 2:08 PM
Subject: SIMM Memory and Pics


> Hello,
>
> I have been following the thread on large storage needed for someones
> project.  Could a SIMM module be hooked up (256K) to a pic.  I could
> dedicate a pic to read/write to this module if necessary.
>
> Has anyone ever done this?  Any web sites with articles/projects like
this?
>
> TIA,
> Brian Gracia