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?

-- 
Regards, Joerg

http://www.analogconsultants.com/

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On Fri, 13 Jun 2008 15:42:27 -0700, Joerg
<n...@removethispacbell.net> 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.

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.  ;)

Jon

Joerg wrote:

> What is you experience with respect to flash errors on uC that are 
> exposed to elevated temperatures as most outdoors applications are?

  Our boxes never see direct sun exposure on the semis, but they're encased in 
an aluminium box, then in a black plastic 'pelican' waterproof case.  Here in 
Australia, it gets quite warmish over summer, and we routinely see the insides 
at 50C (122F) or more (as far as the measurement of the internal temp sensor 
goes anyway).

  Our flash chips are quite ancient, and although they don't hold any critical 
information, it's critical enough that you're going to notice if it chucks a 
wobbly.

  Although we get some with corrupt flash data, it's relatively rare.
-- 
Linux Registered User # 302622
<http://counter.li.org>;

Joerg 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?
> 
One of my clients makes products that regularly go above 80C, and that 
has never been an issue to my knowledge (all the service guys I used to 
hang with have either left or been promoted, so I don't have that 
immediate knowledge one gets by being service's life line).  Certainly 
the to-do if it were recognized would have bubbled down to me.

OTOH, all the parts are very carefully selected to work over the 
industrial temperature range; if your mailbox thingie is designed with 
commercial temp range parts all bets are off (and it may be something 
else that's happening, too).

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Jonathan Kirwan wrote:
> On Fri, 13 Jun 2008 15:42:27 -0700, Joerg
> <n...@removethispacbell.net> 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 :-(


> 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.

-- 
Regards, Joerg

http://www.analogconsultants.com/

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John Tserkezis wrote:
> Joerg wrote:
> 
>> What is you experience with respect to flash errors on uC that are 
>> exposed to elevated temperatures as most outdoors applications are?
> 
>  Our boxes never see direct sun exposure on the semis, but they're 
> encased in an aluminium box, then in a black plastic 'pelican' 
> waterproof case.  Here in Australia, it gets quite warmish over summer, 
> and we routinely see the insides at 50C (122F) or more (as far as the 
> measurement of the internal temp sensor goes anyway).
> 

50C is easy, we even get that as an ambient temperature around here. But 
in summer stuff inside of enclosures can easily reach 80C or more. Worst 
case for 10h/day all summer.


>  Our flash chips are quite ancient, and although they don't hold any 
> critical information, it's critical enough that you're going to notice 
> if it chucks a wobbly.


Chucks a wobbly, cool. Learned a new expression!

> 
>  Although we get some with corrupt flash data, it's relatively rare.


Depends on what "relatively rare" means ;-)

-- 
Regards, Joerg

http://www.analogconsultants.com/

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Use another domain or send PM.

Tim Wescott wrote:
> Joerg 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?
>>
> One of my clients makes products that regularly go above 80C, and that 
> has never been an issue to my knowledge (all the service guys I used to 
> hang with have either left or been promoted, so I don't have that 
> immediate knowledge one gets by being service's life line).  Certainly 
> the to-do if it were recognized would have bubbled down to me.
> 

Well, in my case it kind of has bubbled down to me now ;-)


> OTOH, all the parts are very carefully selected to work over the 
> industrial temperature range; if your mailbox thingie is designed with 
> commercial temp range parts all bets are off (and it may be something 
> else that's happening, too).
> 

It's not just this mailbox but also some MSP430 apps at a client. They 
predate my involvement there and we are pretty much stuck with that for 
a while. We are seeing a distinct pattern where those inside smaller 
boxes fail more often than those in larger and more airy enclosures. 
This stuff is used in the south where summers are quite toasty.

-- 
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

Joerg wrote:
> Tim Wescott wrote:
>> Joerg 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?
>>>
>> One of my clients makes products that regularly go above 80C, and that 
>> has never been an issue to my knowledge (all the service guys I used 
>> to hang with have either left or been promoted, so I don't have that 
>> immediate knowledge one gets by being service's life line).  Certainly 
>> the to-do if it were recognized would have bubbled down to me.
>>
> 
> Well, in my case it kind of has bubbled down to me now ;-)
> 
> 
>> OTOH, all the parts are very carefully selected to work over the 
>> industrial temperature range; if your mailbox thingie is designed with 
>> commercial temp range parts all bets are off (and it may be something 
>> else that's happening, too).
>>
> 
> It's not just this mailbox but also some MSP430 apps at a client. They 
> predate my involvement there and we are pretty much stuck with that for 
> a while. We are seeing a distinct pattern where those inside smaller 
> boxes fail more often than those in larger and more airy enclosures. 
> This stuff is used in the south where summers are quite toasty.
> 
Have you tried cooking them on purpose?  Even if you don't have a "real" 
environmental chamber, you can do a lot with an insulated box and a heat 
gun (including catching the lab on fire (ask me how I know!), but that 
usually entertains the technicians).

I'd toss some in an oven for an extended high-temperature test, to see 
where they failed.

I'd also check the heat rise against ambient in both small and large 
enclosures.

If they get any solar load, I'd throw up my hands and call a mechanical 
engineer who's good with thermodynamics, but that's just because I 
(usually) know where my competence ends.

Some of the flash parts that I have seen used to success have been from 
TI, but they aren't TMS430s, and they _are_ industrial temperature range 
parts.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott wrote:
> Joerg wrote:
>> Tim Wescott wrote:
>>> Joerg 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?
>>>>
>>> One of my clients makes products that regularly go above 80C, and 
>>> that has never been an issue to my knowledge (all the service guys I 
>>> used to hang with have either left or been promoted, so I don't have 
>>> that immediate knowledge one gets by being service's life line).  
>>> Certainly the to-do if it were recognized would have bubbled down to me.
>>>
>>
>> Well, in my case it kind of has bubbled down to me now ;-)
>>
>>
>>> OTOH, all the parts are very carefully selected to work over the 
>>> industrial temperature range; if your mailbox thingie is designed 
>>> with commercial temp range parts all bets are off (and it may be 
>>> something else that's happening, too).
>>>
>>
>> It's not just this mailbox but also some MSP430 apps at a client. They 
>> predate my involvement there and we are pretty much stuck with that 
>> for a while. We are seeing a distinct pattern where those inside 
>> smaller boxes fail more often than those in larger and more airy 
>> enclosures. This stuff is used in the south where summers are quite 
>> toasty.
>>
> Have you tried cooking them on purpose?  Even if you don't have a "real" 
> environmental chamber, you can do a lot with an insulated box and a heat 
> gun (including catching the lab on fire (ask me how I know!), but that 
> usually entertains the technicians).
> 

That I haven't tried yet. A friend of mine (chemical engineer) did 
something similar. After an extended hospital stay he casually mentioned 
that his lab was now a black hole and that the door was gone.


> I'd toss some in an oven for an extended high-temperature test, to see 
> where they failed.
> 
> I'd also check the heat rise against ambient in both small and large 
> enclosures.
> 

That's what I suggested to the client, to place some USB temp loggers in 
there.


> If they get any solar load, I'd throw up my hands and call a mechanical 
> engineer who's good with thermodynamics, but that's just because I 
> (usually) know where my competence ends.
> 
> Some of the flash parts that I have seen used to success have been from 
> TI, but they aren't TMS430s, and they _are_ industrial temperature range 
> parts.
> 

I wish the MSP430 was available in automotive but it ain't. At least not 
according to the TI rep.

One could add some code so it re-flashes itself once in a while, that's 
another option here. However, the device cannot lose power during that 
brief period or it'll be really toast. So that would require large 
enough electrolytics and some pre-regulator voltage monitoring. The 
latter would require a relayout, bigger ECO and all that. Not a VP of 
Engineering's favorite path, usually.

-- 
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

Jamie wrote:
> Tim Wescott wrote:
> 
>> Joerg wrote:
>>
>>> Tim Wescott wrote:
>>>
>>>> Joerg 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?
>>>>>
>>>> One of my clients makes products that regularly go above 80C, and 
>>>> that has never been an issue to my knowledge (all the service guys I 
>>>> used to hang with have either left or been promoted, so I don't have 
>>>> that immediate knowledge one gets by being service's life line).  
>>>> Certainly the to-do if it were recognized would have bubbled down to 
>>>> me.
>>>>
>>>
>>> Well, in my case it kind of has bubbled down to me now ;-)
>>>
>>>
>>>> OTOH, all the parts are very carefully selected to work over the 
>>>> industrial temperature range; if your mailbox thingie is designed 
>>>> with commercial temp range parts all bets are off (and it may be 
>>>> something else that's happening, too).
>>>>
>>>
>>> It's not just this mailbox but also some MSP430 apps at a client. 
>>> They predate my involvement there and we are pretty much stuck with 
>>> that for a while. We are seeing a distinct pattern where those inside 
>>> smaller boxes fail more often than those in larger and more airy 
>>> enclosures. This stuff is used in the south where summers are quite 
>>> toasty.
>>>
>> Have you tried cooking them on purpose?  Even if you don't have a 
>> "real" environmental chamber, you can do a lot with an insulated box 
>> and a heat gun (including catching the lab on fire (ask me how I 
>> know!), but that usually entertains the technicians).
>>
>> I'd toss some in an oven for an extended high-temperature test, to see 
>> where they failed.
>>
>> I'd also check the heat rise against ambient in both small and large 
>> enclosures.
>>
>> If they get any solar load, I'd throw up my hands and call a 
>> mechanical engineer who's good with thermodynamics, but that's just 
>> because I (usually) know where my competence ends.
>>
>> Some of the flash parts that I have seen used to success have been 
>> from TI, but they aren't TMS430s, and they _are_ industrial 
>> temperature range parts.
>>
> I have found strong R.F. and EMF's in close proximity have caused the
> flash to get corrupted in PIC's. I'm sure it effects others.
> 

What do you mean by strong? VHF radio close by? Cell phone? If yes, do 
you remember how close?

-- 
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.