Re: Flash retention in uC at higher temps, experience?

On Fri, 13 Jun 2008 16:23:42 -0700, Joerg
<notthisjoergsch@[EMAIL PROTECTED]
> wrote:

>Jonathan Kirwan wrote:
>> On Fri, 13 Jun 2008 15:42:27 -0700, Joerg
>> <notthisjoergsch@[EMAIL PROTECTED]
> wrote:
>> 
>>> Hello All,
>>>
>>> After some problems a client saw I was treated to my own dose of what
is 
>>> likely flash loss: The uC in our mailbox door has become erratic. I 
>>> installed it about three months ago and half of the day it receives a 
>>> good pelting from the sun. First it began not recognizing some keys, 
>>> then it started doing weird stuff like lock cycling. Things it wasn't 
>>> meant to ever do. Batteries, contacts and such look ok, reset didn't 
>>> help, so that's not it.
>>>
>>> TI has an app note about the topic:
>>> http://focus.ti.com/lit/an/slaa392/slaa392.pdf
>>>
>>> Figure 1 looks scary above the 80C range. Later they presented another

>>> test with a different bake cycle which makes things look better but
who 
>>> knows.
>>>
>>> What is you experience with respect to flash errors on uC that are 
>>> exposed to elevated temperatures as most outdoors applications are?
>> 
>> I only have some small experience here with the MSP430.  It seems to
>> operate at 140C at 3V and 3.3V for the several-hour long tests I've
>> done.  But some bad experiences in storing data into the flash at that
>> temp and even at 3.3V and higher.  But I didn't need the darn thing to
>> survive all that long, either.
>
>Wow, problems within hours at 140C? Not cool :-(

No.  No problems, at all.  Just that I didn't run them for more than
about 5 hours at a time.  Same one ran for weeks, though, at periodic
elevated temperatures.  I was just collecting data from a rotating hot
surface and wanted to just stick the whole contraption there while it
stored a few bits of data into RAM.  The battery was the problem.

>> I haven't read, for understanding, the data sheet you mentioned.  I
>> just downloaded it, though, and thanks for pointing it up.  I think it
>> wasn't around when I looked a few years back and I'm glad that you
>> pointed it up for me.
>> 
>> Your obvious solution is to move north about a thousand miles.  ;)
>
>My wife would absolutely not do that.

Oregon is absolutely beautiful!  I've got pileated woodpeckers, 4
kinds of squirrels including a flying squirrel (nocturnal), peafowl,
chickens, guinea hens, turkeys and so on -- tall 60-80 year old firs,
two kinds of ferns, rhododendrons that bloom in succession around the
place, and it looks like a lush rain-forest national forest when you
walk the paths on the property.  Lots of acres, 5000 sq ft home, 1/4
mile driveway to the house, view of the mountains, 5 minutes to a
hospital and 20 minutes to the PDX international air****t, a 17 mile
well-maintained walking and horse trail that goes from 1/2 mile away
from my home to the Willamette River in ****tland, and it cost me $330k
in 2002.  Prices are still low, too.  Next door has been on the block
for 2 years, is a million dollar home (tax appraisal price) with about
4500 sq ft and 5 acres, and is being offered at $599k now.  I'm told
they'd accept under $500k.  Neighbors are wonderful, too.

3' of fantastic soils, 45" of rain a year nice and evenly distributed
all year 'round in a constant drizzle, and everything grows where you
throw the seed, no digging needed.  What could be better?  ;)

Jon