nRF52: Write/erase flash cycles confusion

[ThierryQ]

Hi,

I have a small question regarding flash write/erase cycles and I was unable to find a clear answer.

I can see in NRF52 specs:

• Flash write/erase cycles: 10 000.
• Amount of writes allowed in a block between erase: 181

I would like to know if 10000 is related to write + erase or only erase.

I means, if I have below scenario:

• erase page1
• write page1 (10bytes)
• write page1 (+10bytes)

How many flash cycle I will consume ? 1 or 3 ?

Thank you,

Thierry.

[Hung Bui]

@Thierry: Our confirmation is that one cycle includes one erase and one write. So 10000 erase/write cycle mean you can do 10000 erase and 10000 write.

[vit bernatik]

I do not understand your answer. The write is by 4B. The smallest block that can be erased has 0x200 B. So in order to fill it after erase you would need erase + 128 times write. I'm quite sure that these 128 times of write won't count as 128 "endurance cycles". To my understanding erase + 128 times write is one endurance cycle. The question is how it is counted when you write to same word. In datasheet nRF52832_PS_v1.1 is written that Amount of writes allowed in a block between erase is up to 181. So I assume one endurance cycle is even more -> 1 erase + 181 writes. And of course you can not write more times without erase. As I understand if you write more you risk that some of "1" that you did not try to clear can be cleared unintentionally.