Hi, i am writing regarding the STMF040B, - Which is the data retention of the device? - If I reprogram the STMF040B what will be the “new�? data retention? Will “restart�? the countdown or will continue with the old one? Thank you for help

[Tesla DeLorean]

What is the STMF040B ? Is it a discontinued product?

The FLASH in STM32 devices is normally rated at 10K cycles, retention tends to be a function of temperature and wear level of cells. 7-30 years depending on situation. Typically based on the last erase/program cycle, but multi-factor.

What does the Data Sheet say?

[SRaim.1]

thank you for your answer

this is what datasheet reports, 20 years, actually my flash memory has been programmed in 1999, so i would like to know if with the re-programming of the device my flash will have data retention for other 20 years or it will lose data in few days.

[Peter BENSCH]

You are currently talking about the M29F040B flash memory, which was spun off with the entire business unit in 2007 to the company Numonyx, which in turn was subsequently taken over by Micron, but Micron has also discontinued this ancient 5V technology.

Although there is no longer any documentation for these very old devices, it can be said that the 20-year data retention is a minimum value. With normal, not too strongly changing ambient temperatures, one can usually assume much longer periods for data retention - the flash does not suddenly forget its entire content after 20 years and one day.

Temperature cycles can cause the gate charge of the flash transistors that carry the bit information to decrease (you can think of this as a "drop" in the charge level). Reprogramming may be able to compensate for this effect. If you have the possibility of deleting the component and programming it again, you are welcome to do so. Of course, no one can give a guarantee for another 20 years.

Good luck!

Regards

/Peter

[Tesla DeLorean]

I would read it and archive a copy, in several forms.

Perhaps burn the content into a newer part, or several, depending on the equipment this might be better or worse than the original / contemporaneous tools.

I would expect these devices to have a significant usable life-span, especially if written once and left alone.

Perhaps program a replacement part, put it in an envelope within the product with a note to your future self, or the person who replaces you.

In 10 or 20 years the availability of the part, and the means/skill to replace and reprogram it will be diminished.