MC9S12DP256 C Flash Lifetime

[TimBolbrock]

I am programming a simple robot for research use using the MC9S12DP256C. The only specifications I can find indicate the flash lifetime as 10 cycles / 15 years. I also find vague information that you should be able to cycle the flash much more than 10 times, only losing the 15 year retention, but nothing that makes me feel sure enough to actually go and do it without confirming first. These robots would be reprogrammed often as research progresses or as they are used for different projects - I am providing the basic motion/communications/sensor platform for others to write applications for. Since the users will be in a position to reprogram the robot at any time data retention is not really an issue unless it gets down to something absurd like 2 hours. This would be at room temperature conditions. Am I correct in my idea that the flash can be reprogrammed hundreds-thousands of times without breaking down?

Thanks,

Tim

Message Edited by Tim Bolbrock on 2006-08-10 03:58 PM

[peg]

Hi Tim,

Not sure where you got 10 times from.

It is more like 10,000 times.

In reality you are far, far more likely to loose the chip from some other accident during this process than wearing it out from to much flashing.

Regards David

[TimBolbrock]

Section A.3.2 of 9S12DP256BDGV2.pdf in this file http://www.freescale.com/files/microcontrollers/doc/data_sheet/9S12DP256B.zip says 10 cycles/15 years for flash and 10,000 cycles/5 years for EEPROM. That is for the 256B, though, whereas I have the C but can't find any specs for that. It does seem very incongruously low to me, which is why I'm trying to find out if that's just the 15 year guarantee that's gone after 10 cycles or if I really should expect it to fail after 10-20 cycles.

--Tim

[Alban]

Tim, make sure you are using a better device, if you want to be certain.

9S12DPxB or C is different device from 9S12DPx.

The difference between the two being a change in the Non Volatile Memory technology to extend retention/endurance.

Make sure you do use a 9S12DPx device and not with a B or C if you want to extended memory life !

Cheers,
Alban.

Message Edited by Alban on 2006-08-11 11:26 AM

[SteveRussell]

The flash lifetime specifications seem to be very conservative, and based on programming and operation at worst case temperature extremes. 

Most of the current production HCS-12 parts are specified at 100 erase write cycles.

In practice, some people have reported several thousand erase write cycles on HCS-12 parts at room temperature with no signs of problems.

Some of the early MC9S12D series parts had errata associated with flash, so check the errata for your mask set. 

As long as you don't erase flash automatically at frequent intervals, and you're not operating at the ends of the temperature range, you shouldn't have to worry.