I wonder how often I can flash an ATtiny85 before the EEPROM will give up.


Sometimes it is just on the first page of the datasheet:

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  • \$\begingroup\$ After the ten-thousanth time...you might ask how long it remains flashed before leaking bits. \$\endgroup\$
    – glen_geek
    Mar 18 at 16:46
  • \$\begingroup\$ How long do you think it will remain flashed before leaking bits? \$\endgroup\$ Mar 18 at 16:54
  • 1
    \$\begingroup\$ stackexchange has at least an 11-year memory: electronics.stackexchange.com/questions/16183/… \$\endgroup\$
    – glen_geek
    Mar 18 at 17:01

1 Answer 1


It reads on the first page of the data sheet.

EEPROM is specified for 100000 write/erase cycles.

It does not depend on how often you do it, no matter how fast or slow it still is 100000 write/erase cycles.

  • \$\begingroup\$ Oh so often, that I didn't expect! \$\endgroup\$ Mar 18 at 16:53
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    \$\begingroup\$ Some caveats apply. The EEPROM page size is 4 bytes so if you write four bytes all four memory locations are erased and written four times. Unless you mean the program flash. That's only 10000. \$\endgroup\$
    – Justme
    Mar 18 at 16:58
  • \$\begingroup\$ It seems that I might have meant the flash memory instead of the EEPROM. I use Arduino IDE to upload a simple sketch. To my shame, I don't know what the difference is yet. \$\endgroup\$ Mar 18 at 17:06
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    \$\begingroup\$ Then you mean the program memory flash. \$\endgroup\$
    – Justme
    Mar 18 at 17:08
  • \$\begingroup\$ Then even 10,000 cycles should be reasonable. I have mistakenly assumed the limit would be way more less (about 50-100 cycles) and so thought it would be risky to flash it too often during development before I finish my project. \$\endgroup\$ Mar 18 at 17:11

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