SDK15.2 fds write operation problem

[Jray]

Hi Nordic,

    A problem was found with the SDK15.2 write operation. If the write size is equal to 12000 bytes, the system will return an invalid operation length error.

But this write length is uint32_t .

If you change the write length to 6000 bytes, you can write successfully.So what is the cause of this?

Looking forward to your reply!

[Einar Thorsrud]

Hi,

You are attempting to write a larger record than allowed. From fds_record_write() API doc: "The length of the data must not exceed FDS_VIRTUAL_PAGE_SIZE words minus 14 bytes".

[Jray]

Hi Einar,

Thanks for your reply!

Do you mean that the maximum cannot exceed 2048*4-14 bytes? if FDS_VIRTUAL_PAGE_SIZE = 2048.

[Einar Thorsrud]

Hi,

The line I pasted from the documentation is unclear because it mixes words and bytes, and in fact it is not entirely correct either. In practice, the maximum number of words you can write is FDS_VIRTUAL_PAGE_SIZE - 6, which would be 2042 words in this case (8168 bytes). See this thread for details.

[Jray]

Ok, Thanks Einar !