My flash memory device A25L032 has 64 one time programmable bytes. It also has software and hardware protection modes for blocks, sectors as well as the whole chip.

What application do one time programmable bits have since flash is nonvolatile anyway and we also have protection modes for blocks and sectors.


1 Answer 1


Product serial number, among other things.

  • 3
    \$\begingroup\$ Just to expand, a short list of things that I've used them for: serial number, hardware IDs, checksum for the bootloader. One of the more surprising uses is that we ended up using them as "hard coded" information for IO pins for a shared code base between processors. That let us have a "generic" C architecture and then just some custom code to read in those values that then configured the port selections. They could be hard coded because the hardware is, of course, static \$\endgroup\$
    – b degnan
    Jun 11, 2016 at 21:46

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