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what exactly do I need softdevice_sys_evt_handler for?

Hi

I am using SDK12 with NRF51822,

So far I haven’t initialized the sys_evt_handler (softdevice_sys_evt_handler_set(sys_evt_dispatch)) And my program works fine,

Ive seen a thread mentioning that it is used for NVMC,

but I have used sd_flash_write successfully to write to flash, what will I gain from using this handler when writing to flash or in general?

I would like to get some more understanding about this issue, what exactly are the events this meant to handle, what is its importance? Preferably with some examples.

Thanks!

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  • Hi,

    The Softdevice flash API is asynchronous meaning that the completion of the flash operation will be completed at some point after the program has returned from sd_flash_write(). So to know if a scheduled flash operation was successful or not, you need to monitor the system events through the registered sys event hander. A flash operation should either result in NRF_EVT_FLASH_OPERATION_SUCCESS or NRF_EVT_FLASH_OPERATION_ERROR if the Softdevice was somehow prevented from scheduling the task. 

    Our fds and fstorage modules builds on top of the sd flash API where the system events to notify the user whether a flash operation was completed successfully, or if it timed out.

    The main reason a scheduled flash operation can fail is if you have a lot of protocol activity, please refer to the Flash API section in the Softdevice specification here for more details: Flash memory API

  • Hey Vidar

    Are there more examples the might necessitate using the sys event handler? other than flash write?

    Thanks and have a great day

  • Generally yes. But it is possible to use the radio in allocated "timeslots" through the Softdevice's multiprotocol feature. Multiprotocol support

  • Hey Vidar, 

    A few more questions , 


    1. setting softdevice_sys_evt_handler - sys_evt_dispatch, disturbs RTT Jlink after a I preform a write to flash. why is that? I see it got there and printed the last log from there, the software still works but as I said my JLINK RTT viewer stops showing updates, closing and opening the RTT viewer does not help.

    2. I don't implement bonding currently, so I think I have no need for pstorage, in the example of implementation of sys_evt_dispatch that I saw there was 2 calls for : pstorage_sys_event_handler(sys_evt) and ble_advertising_on_sys_evt(sys_evt), do I need to call them in my application? (I also don't use multi protocol)

    Thanks!

  • Hi,

    1. RTT should not be directly impacted by flash operations. Are you able to debug the application to see if NRF_LOG_PROCESS gets called after you've enabled the sys_event_handler?

    2. No, if you only use sd_flash_* API's you don't. You can just check the event ID in the dispatcher to see if it was NRF_EVT_FLASH_OPERATION_SUCCESS or NRF_EVT_FLASH_OPERATION_ERROR.

    if (sys_evt == NRF_EVT_FLASH_OPERATION_SUCCESS )

    { ..}

    else if (sys_evt == NRF_EVT_FLASH_OPERATION_SUCCESS)

    {..} // flash operation failed. Retry later?

  • Hey,

    1. It is getting called after enabling the handler, it stops working only after the handler is actually called, I can see that everything else is working via other interfaces including the ble.

    2. Yes, that's exactly what I wanted to do. but as I said, it disturbs the entire logging process.

    Thanks for your help.

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