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

Jonathan Kirwan wrote:
> 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.
> 


However, you said "But some bad experiences in storing data into the 
flash at that temp and even at 3.3V and higher."


>>> 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.
> 

That sure sounds mouth-watering. But my wife likes places where there is 
no winter (and now ours get colder every year ...) and I'd have a wee 
problem with the property tax rates up there. 2% or more is IMHO 
confiscatory. Oh, and I like proposition 13 (prop tax increase cap) in 
California because I do not trust politicians enough to toss them the 
keys to my bank account.


> 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?  ;)
> 

Ah, you shouldn't have written "drizzle", my wife would hate that kind 
of weather.

-- 
Regards, Joerg

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