fds write data before sleep

[JohnathanLyu]

Hi community,

Try use FDS to write some data before sleep.

Following example and test is work.

But I try write data before into

sd_power_system_off();

and it not work. Then I try create app_timer count down with idle time come. Not work too.

How do I write data before into sleep mode?

[Jørgen Holmefjord]

Hi,

Could you explain in more details what is not working? Is the data not written to flash, is an error code returned, etc.? This is copyed from the documentation:

Initialization, like all other operations in FDS that involve writing or erasing flash memory, is an asynchronous operation. Completion of the operation is reported to the application through a callback.

Before going to sleep, you should wait for the event in the event handler corresponding to the last FDS operation. The relevant events are defined in fds_evt_id_t.

If you make a call to fds_record_write(), you should wait for the FDS_EVT_WRITE event before going to sleep.

Best regards,

Jørgen

[JohnathanLyu]

Hi Jørgen,

I can compile well and flash to board is fine.

But when run to idle prepare to sleep is hang in there. I put the fds_record_write() into sleep_mode_enter() to write data.

I could get work if I put fds_record_write() in main(). But I try to make write data before sleep to update last data.

I also try to put fds_record_write() data app_timer_create() to count down every seconds to write. But it just stop there.

[JohnathanLyu]

Hi Jorgen ,

Look like I wait FDS_EVT_WRITE to triger flag to exit while loop not set flag up. So it seem stuck in loop forever. But If I put fds_record_write() then while wait complete in main() it's work fine.

[Jørgen Holmefjord]

It might be a priority issue. If you try to write to FDS from an interrupt context with same or higher priority than FDS, the flag will never get set. Why can't you do the write from main before going to sleep?

[JohnathanLyu]

In my case I will use ADC read value and do some math. Board not be always on, so I try to record before sleep. Make sure last data when next time wake will remember last state and don't care is have power.

Is any suggestion let me record before sleep?