Flash resource for ESP8285

[dn_1983]

Hello.

I didn't find official information, what is resource of ESP8266 flash memory, how many cycles can I re-write it?

Thank you.

[Sprite]

Depends on the module (as the ESP8266 does not have built-in flash) but generally 10.000 to 100.000 times is standard for SPI flash chips. Note that this is per sector, and wear-leveling techniques as used by nvs, spiffs, littlefs etc extend this number at the cost of requiring more space.

[dn_1983]

(as the ESP8266 does not have built-in flash)

Sorry, I wrote wrong information.
I use ESP8285 chip, which has internal flash memory.

Could you please share information for this chip?

[dn_1983]

One more question.
How much time does it take to write one sector (in ms) for ESP8285?

P.S. Could you please rename this topic from "Flash resource for ESP8266" to "Flash resource for ESP8285"?

Thank you.

[Sprite]

Sorry, if the datasheet doesn't state it, it's technically unspecified. I imagine the specs are similar to the ESP32, though, which states >100000 erase cycles but not specifies a write duration.

[dn_1983]

I would like to share my researches.

Firstly, I've done measurements with help of oscilloscope.
Operation of writing consists of two stages: erase sector(obligatory) and then write sector.
Erasing one sector takes about 48ms, while writing takes just 2.2ms.

After this, I decided to write one sector as many times as possible.
I did it in a cycle, and it achieved 170 000 times.
And internal flash memory was still alive.

Amazing results, I expected worse.

But, time intervals have increased.

Erasing one sector become about 200ms - 240ms, while writing become 4ms.

Hope this information will be useful.

[MicroController]

I did it in a cycle, and it achieved 170 000 times.
And internal flash memory was still alive.

Amazing results, I expected worse.

Just a note: With flash memory, "alive" is relative. After that many writes, the storage bits may have degraded somewhat and not meet the original specs anymore. "Data retention", for example, may be spec'd at 10 years, but after exceeding the specified maximum number of erase/write cycles, it could in theory go down a lot, e.g. to a month or a week.

However, the specs are usually guarantees for worst-case scenarios, i.e. cycling at the permissible limits of supply voltage and temperature, so in 'friendly' conditions there may actually be much more 'juice' in a chip than guaranteed by the manufacturer.

[dn_1983]

Just a note: With flash memory, "alive" is relative.

You are right, thanks for the clarification.