Write to FLASH inside BLE event

[schef]

Hello, i have read if not all posts about writing to FLASH while using BLE. But could not find the desirable method.

What i would like to do is to write to flash from characteristic write as it comes. The problem is that sd_flash_write is asynchronous.

So i have to block the device until the write has finished or else the writen data may get corrupted. The only way to know that the sd_flash_write had finished is to wait for NRF_EVT_FLASH_OPERATION_SUCCESS inside sys_evt_handler.

But as some other post mentioned if you call the flash command inside the ble event you don't get the response.

One way to get the response is to store the data somewhere, make a flag which is looked up in the main context. But that means that i am limited to the array size i am storing data in.

Isn't there a way to write directly synchronous from the BLE event or at least to somehow block the further execution untill i get the event?

I'm using nrf52832 with sdk 12.2

Thanks

[Hung Bui]

• Sorry I didn't get you at the beginning. Yes, you are correct. This is due to the nature that flash operation will block all CPU activity, so we need to let the softdevice control when to execute flash. And yes, then you will need to wait for NRF_EVT_FLASH_OPERATION_SUCCESS inside sys_evt_handler. And if you put a loop inside the interrupt handler to wait, you will not receive the NRF_EVT_FLASH_OPERATION_SUCCESS event because you still inside the interrupt handler with same priority level.

• The local variable with large data you need to store, does it have to be in the BLE event handler ? If it's in the APP Low event handler then it's possible to wait for the event there because APP Low has lower priority than the BLE event.