Flash retention in uC at higher temps, experience?

applications must live in plastic boxes and there is always a

someone fires up a cell phone and the GSM ones can be

It could be a design with long supply wires (as antennas) and poor RF blocking caps close to uCPU.

Flash corruption due to EM field at 6 feet distance sounds a bit far fetched.

it practically means

Wow, looks like they are making progress. The last unit I used was 64K serial (I2C) from Ramtron and it was limited to 10^12 read/write cycles which came out as years at max I2C bus speed.

I love mram, however these things are sensitive to magnetic field, right? Still not exactly bullet proof.

I suggest you paint your box or faceplate a different color.

Your aim should be to avoid producing temperatures that are not neccessary in direct sunlight.

RL

(serial) it practically means

(I2C) from Ramtron

I2C bus speed.

First the Ramtron devices are FeRam not MRAM.

Second Ramtron has also been claiming unlimited writes for some time now. IIRC the limit was a function of axygen contamination. Apparently they solved that problem.

Robert

Not so easy on an existing product. But from experience it seems the temps weren't all that different between a black box and an off-white one. Maybe the off-white one crept up a little slower.

Yes, I did. I gather you want to do that.

My place is appraised at $850k (down there, I know that is just a shack but up here it's 5000 sq ft of quality, showy home and lots of acres of prime hilltop land) and my property taxes are $4400/year. Which is kind of high, I admit. It's the income taxes you'll probably hate. It's a graduated rate, but I think the top rate (which applies to most engineers, without even asking) is 9%. However, no sales tax.

I did that on purpose. I didn't want to make it seem too inviting. Actually, I've come to appreciate the constant press of low clouds overhead and the slippery feel of moist moss as you carefully walk across your one year old, rotting wooden deck.

Jon

and they also have a 140'C rated variant....

They do seem to be expanding use of Digikey.

Digikey shows 4,153 Infineon items, of which 275 are Microcontrollers, and of those 46 are XC8xx series.

-jg

Our family grows/raises most of the food we consume. It's nice knowing where it all comes from and how it was treated and prepared.

I don't have all that within walking distance. It's a 5 minute drive to the nearest hospital, for example, and 20 minutes drive to an international airport (PDX.) But we do have a grocery store (not a supermarket), a pub, a restaurant or two, and many, many parks all within easy walking distance of home.

Okay. I'm having fun. I hope you don't mind if I post a few links to pictures.

These pictures are from my own land, showing paths that proceed from my home into the wooded parts of my property:

That will give you a flavor for the flora.

Mt. Hood rises up from sea level to about 11,300' and is about 15 miles from my home. Here is how it looks from a lake that is very close to my home (in the summer):

This water fall (among literally more than a hundred within a short distance) is about a 15 minute drive from home.. over 600 feet:

The Columbia River flows by Mt. Hood's northern base. This viewpoint is actually closer to my home than the above falls -- about a 10 minute drive:

All of the above is in relatively easy bicycling distance.

In Oregon, it is illegal to own or fence or otherwise control coastal land. Some 400 miles of coastline is public land. The only state of the USA that does this, I think. In any case, here is one photo of what our coast partly looks like:

Jon

applications must live in plastic boxes and there is always a

someone fires up a cell phone and the GSM ones can be

It will not be a Direct Flash Cell effect, but more likely a Software crash, that jumps into a Flash Write routine.

This is one reason why many Automotive designs insist on a FLASH_ENABLE pin, so that a simple SW crash CANNOT cause un-recoverable damage.

We have some designs that will NOT use IAP Flash controllers, for exactly the same reason.

Adding IAP is a convenient feature, but it also can be a point of weakness.

-jg

Not quite: The latest Mar 2008 data for the FM25H20 2MBit FRAM, (40MHz) specs 10^14 Wd/Wr, (which I guess is per Byte?).

Most data application will be well under that, but it could start to bother an execute-from-flash design, sitting in a tight loop.

These parts have very Niche-prices, around 20x that of vanilla flash, so you really have to need their better features :)

-jg

I'm working with an 89lpc952 (Phillips/NXT) which comes preprogrammed with a bootloader in the top Flash sector. There's a flag that, when set, will cause execution to start there instead of the normal reset vector.

You're free to overwrite the bootloader with something else, so perhaps that facility could be used for one side of the flipflop?

Of course, the '952 also has IAP which I don't think can be disabled...

And it's well known that (western) Oregonians don't tan, they rust.

Interesting. Their lower density parts like FM25L512 quote unlimited read/write cycles. Maybe endurance issues have arisen again at finer geometries?

For small sizes the price premium over EE is small. I use them for the security of a faster write (the memory is vulnerable for a smaller window).

Robert

With all other variables constant, a reduced rate of rise means a lower end-point of thermal burden. Light colours are preferable where reflective surfaces are not possible.

Changing the material, or material grade to something that is not clear/opaque to infrared can also have an effect. A paint overcoat rather than internal pigment (~of plastic). Adding irregular surface finish or stippling/ridging may also have a beneficial effect.

Failing that, a sacrificial face-plate on the most exposed surfaces, decoupled physically from the case itself.

RL

;)

I just spent a nice day today at a fly-in for nitro and electric helicopter models. It was a nice day of about 64-67F and I spent about 5 hours in the 45-degree N latitude sun. Horrible sunburn I'm sitting here suffering from, right now! (I get 2nd degree burns in 15 minutes in LA, by the way. I need the cloud cover!)

Jon

It does looks terrific and with all the woodpeckers squirrles and whatnot it sounds like a paradise for the camera-hunter I have become lately. But what about winter? How long/harsh is it typically? (Not last winter, I guess we are all still expecting it to quite go away in mid June... :-) ).

Didi

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Original message:

Or they insist that flash-write routines simply don't exist in the application. A routine that's not physically present in the chip can't accidentally be run. Nice and simple, really.

They only get uploaded into the controller RAM at flash-update time.

Yep, I thought that was the real cause. I think Joerg pointed out GSM phones can be especially nasty with their pulsed carrier.

so that a simple SW crash CANNOT cause un-recoverable

I suspect the programmed fuses that should prevent writing over flash section may not always work. External pin is probably more reliable.

Ok, still two orders of magnitude improvement. The bad part is it applies to reading as well :(

The 64K I2C parts were 1-2 euro AFAIR. 4M freescale part is another story. I like them for speed and the fact they can't be destroyed by runaway software, at least in I2C variant.