Question flash memory and retention files

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classicsamus87

Joined Oct 1, 2020
24
these images are from my board it is the same but i don't know how to flash this hardware and data retention stored unused for long periods
 

dl324

Joined Mar 30, 2015
11,926
these images are from my board it is the same but i don't know how to flash this hardware and data retention stored unused for long periods
Data retention is on the order of 10-20 years. Have you checked datasheets for the parts used?

NAND flash always require a controller that can recover from flipped bits because the bits are less robust and parts can ship with defective bits that are flagged so they're not used. NOR flash doesn't require error correction, but could benefit from it.

EDIT: corrected capitalization on flash.
 
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dl324

Joined Mar 30, 2015
11,926
this flash memory on the board is NOR flash? is data lost after 10 years inevitable?
I didn't bother to try to get part numbers from the pictures. NOR would be more reliable than NAND, particularly MLC. The 10 years isn't exact. Programmed cells will lose electrons over time. The rate depends on things like temperature and the quality of the gate oxide.
 

dl324

Joined Mar 30, 2015
11,926
after 20 years of storage data is inevitably lost from this NAND flash?
It's a NOR flash and 20 years isn't an exact retention period; it's the minimum.

NOR flash in inherently more reliable than MLC NAND flash. Multi-level cells store at least 2 bits of information in the same memory cell. This requires a specific amount charge to be deposited on the floating gate. The difference in states is only a few thousand electrons. Electron loss can change the value stored in the cell.
 
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