Hi Folks,

Many thanks to those who replied to my PIC/FLASH question.

Both Jim Paul <jamesp@INTERTEX.NET> and Andy Kunz
<support@MONTANADESIGN.COM> said they were happy with the Atmel FLASH part.

When I tried to get hold of some NexFlash parts in Australia, neither of
the distributors had even heard of the company (NexFlash).  The best answer
I got from them was to try an outlet in Taiwan. I can source NexFlash parts
from the US, but they're not cheap. On the other hand, the Atmel parts are
available as a stock item from a local electronics distributor at ~$12
($US7) for one-off quantities. Admittedly, its not quite as good as Jim's
price ($3-4 for the 5v parts), but its certainly a better starting point.

Antonio L Benci <Nino.Benci@SCI.MONASH.EDU.AU> pointed out that its
possible to power these parts from a port pin and switch them off when not
required, thereby reducing the power consumption. I've found this to be a
good technique in the past, and will probably use it to save power on the
A/D converters and the analog system. As Mike Keitz <mkeitz@JUNO.COM>
pointed out, powering down the FLASH parts causes the SRAM contents to be
lost. In my particular case this is a problem, since the devices are
sampling fairly slowly and may take hours (possibly days) to collect enough
data to fill a FLASH sector. Another issue is that if the FLASH is powered
down, the I/O lines (serial in, serial out, clock) can't be used to talk to
other devices (without exceeding the maximum rating of Vcc+0.5V for any
device pin). This may or may not be an issue, depending on how many port
pins I eventually need.

Peter Grey <martech@OZEMAIL.COM.AU> said that he uses 8 x 24LC256s to get 2
megabits storage for his logger. This is another possibility that I
considered. These parts allow bytes to be individually programmed (no
sector requirements) and so could be powered up/down and programmed as
required. If larger density serial flash memories were not available, I
might have chosen this option.

Once again, thanks everyone for your input. On balance, the ATMEL part
looks a little more attractive (especially with my difficulties obtaining
NexFlash supplies). I'll have to look carefully at my power budget once I
have a complete design.

Cheers,
- Stewart