Jason, others,
Dallas make an iButton part with 64k bits N.V. ram,
horrendously expensive, 1 signal wire. parts also have a "turbo mode"
but this still has some limitatations.

code is DS1996

regards Graham Daniel

Dennis Plunkett wrote:
>
> At 08:02 PM 6/05/98 -0700, you wrote:
> >Does anyone know of a serial static RAM I could use for additional PIC
> >data memory?  I am attempting to alter a pre-existing design that uses
> >93C66 EEPROMs, so something with the same pinout and bit-banging scheme
> >would be nice, although not absolutely necessary.  I don't care whether
> >the SRAM is volatile or not.
> >
> >The only firm requirements are three pin interface, minimum 64 bytes RAM
> >per chip (bigger is better), and no write cycle limitations like those
> >associated with EEPROM and FLASH.
> >
> >Bonuses would be:
> >     256 bytes per chip
> >     nonvolatile
> >     8 pin package with pinout similar to 93C66 EEPROM
> >
> >I have searched extensively already, and all that I've found are some
> >XICOR non-volatile SRAMs that aren't large enough, and a variety of
> >parallel parts (including the Dallas RAMPort).  It seems like something
> >like this should exist.  Am I missing something obvious?
> >
> >Oh, I also spoke with a Microchip tech support guy who told me he's had
> >the same problem and was also unable to find a solution.
> >
> >Any help would be greatly appreciated!
> >
> >Jason Harris
> >
> >
>
> If I remember correctly, Philips had an I2C SRAM or around 256 bytes. Your
> other option is shift registers, or perhaps another PIC
>
> Dennis