---------- Forwarded message ---------- Your message is being returned to
you unprocessed because it seems to have been already sent to the PICLIST
list. That is, a message with identical body (but possibly different
headers) has been posted to the list recently, either by you or by someone
else.

OK, I'll add the above text! That should trick it hey?  :-))

> > I'm working on a data aquisition project with a PIC uC involved.
> > Does anybody have an idea about if it's possible to attatch
> > 512 KBytes of NV- Data Memory to any pic controller and if how
> > then how ?? (this sounds stupid!)
> > I would be realy glad if somebody has any idea (If 512 is difficult,
> > then what about 256,128 or 64KBytes)
> >                 Ciao
> >                         Mikael

You could try daisy chaining two Cmos 4040 timers together controlled by
two signals. One clock, for address selection and one for reset to zero
address. By pulsing the clock, you increment the address, an old tried
and true method!

Get an off the shelf 8 bit wide static ram that will have its data lines
connected directly to 8 PIC lines. You then only need to control the
read, write and chip select of the Ram.

Battery backup can be provided by a simple diode/resistor network from any
variety of sources such as Ni-Cad, lithium or a large capacitor. February
95 Circuit Cellar magazine gives examples of doing simple battery backups.

Or you could use a Dallas Ram backup (smart socket) if cost isn't a big
factor.

The last time I purchased Static Rams, the 128K by 8 bit was the most cost
effective, but that was perhaps 18 months ago. This may have changed.
Perhaps you can get your 512K in one IC at a realistic price.

Don...

  Low Cost DIY PCB's for PICs & COM1/LPT1 PC I/O Interface Kits    ;!
  Don McKenzie. 29 Ellesmere Cres., Tullamarine. 3043 Australia    ;@
  Tel +61 3 9338 6286 Mobile  +61 19 939 799 donmck@tbsa.com.au    ;#
  Check My Promo Disk at http://rasi.lr.ttu.ee/~sis/mirror/don/    ;$
  Type: 'finger donmck@tbsa.com.au|more'  for more information.