FDS update returns or changes some part of data randomly.

RE: FDS update returns or changes some part of data randomly.

Einar Thorsrud — Thu, 26 Sep 2019 08:29:10 GMT

Hi,

[quote user="Bharath Gopal"]If it is so, why does it fail only some time? I am using a global buffer every time and the address is always same.[/quote]

I cannot explain that. Can you double-check?

[quote user="Bharath Gopal"]If it is a address alignment issue, how to make sure that the buffer is word aligned?[/quote]

This is only an issue if you are using non-4 byte data types, or for instance structs with some members that are not 4 bytes. Then depending on the packing of the struct, the data may not be aligned. See this post for how to fix it in that case. If that does not help, please share some code showing the data structure you are trying to write to flash and how you write it.

RE: FDS update returns or changes some part of data randomly.

Bharath Gopal — Thu, 26 Sep 2019 06:52:33 GMT

If it is so, why does it fail only some time? I am using a global buffer every time and the address is always same.

If it is a address alignment issue, how to make sure that the buffer is word aligned?

RE: FDS update returns or changes some part of data randomly.

Einar Thorsrud — Wed, 25 Sep 2019 13:29:14 GMT

Hi,

This means that you are providing a pointer to an address that is not a multiple of 4. This is invalid since all flash operations must be word-aligned, and the flash words are 4 byte-sized.

RE: FDS update returns or changes some part of data randomly.

Bharath Gopal — Wed, 25 Sep 2019 10:10:15 GMT

Thanks for the update Einar.

I am calling write function from UART interrupt on receiving some commands. Also, the update pending write is called from FDS_EVT handler.

When I check for the return code inside FDS_EVT handler, it returns code 3 (FDS_ERR_UNALIGNED_ADDR).

What does this error mean?

Thank you,

Bharath

RE: FDS update returns or changes some part of data randomly.

Einar Thorsrud — Wed, 25 Sep 2019 08:24:03 GMT

Hi Bharath,

Good to hear you fixed the initial issue.

[quote user="Bharath Gopal"]At some point when the fds_gc gets called, the callback function calls "FDS_EVT_GC" & I call my write pending function to write back the pending data. But the callback never gets called for update complete after this .[/quote]

It is difficult to say anything specific without seeing your code. But another typical issue when people test FDS is problems with interrupt priorities. Do you by any chance call the write function from the event handler (or a function that is called from there or in another interrupt context)? If so, and if you also wait for the event in a loop, then you will have a deadlock. This is all just guesses though. Please share and explain your code if it does not fit so that I can see what you are actually doing.

RE: FDS update returns or changes some part of data randomly.

Bharath Gopal — Tue, 24 Sep 2019 14:04:28 GMT

Hi Einar Thorsrud,

Thanks for your reply.

I added a variable to check if the write/update is complete in the fds_evnt_callback switch cases. Every time, the variable becomes true and I write data, it succeeds.

At some point when the fds_gc gets called, the callback function calls "FDS_EVT_GC" & I call my write pending function to write back the pending data. But the callback never gets called for update complete after this .

Thank you,

Bharath

RE: FDS update returns or changes some part of data randomly.

Einar Thorsrud — Tue, 24 Sep 2019 11:31:04 GMT

Hi Bharath,

It sounds like you may be reading back the data before the updated record has actually been written. Have you remembered to wait for the event indicating that the flash write operation has completed (succeeded or failed)? This is the FDS_EVT_UPDATE for a record update, or the FDS_EVT_WRITE event when writing a new record.

Einar