How long to advertise for correct DFU?

[jtredez]

Hi,

I use buttonless DFU with the secure bootloader.

When I push a button my application advertise in fast mode with an interval of 40ms and for 5s. After it return to slow mode with advertising interval of 10s and infinitely duration.

I use nRF Toolbox to perform the DFU. I push the device button to advertise in fast mode and perform the DFU. With a timeout of 5s it's very difficult to perform the DFU, so I change it to 10s, now it's better but not in all case.

What fast mode timout do you recommend to secure a good DFU?

Best regards

[Bjørn Kvaale]

With a timeout of 5s it's very difficult to perform the DFU, so I change it to 10s, now it's better but not in all case.

 Could you please explain what you mean by this statement? Why does it not work great in all situations?

It is not a good idea to have an advertising interval of 10 seconds, as it could be very difficult for the phone to connect to this. Are you using sdk 12.3?

[jtredez]

I use SDK 12.3.0.

Fast mode: I advertise at 40ms for 5s or 10s

Slow mode: I advertise at 10s for infinite

When I perform the DFU I am in fast mode, so I advertise at 40ms for 10s. But apparently 10s is not sufficient to establish each time the DFU process (write the DFU caracteristic + reboot to the bootloader + establish the connection with the bootloader + restart with advertising at DFUTarg + start the DFU)

[Bjørn Kvaale]

Hi,

Very sorry for the delayed response. What kind of errors are you receiving when you keep the fast mode timeout at 10 seconds? It is important to remember that the timeout will expire once you have established a connection between the smartphone & the peripheral you want to do the dfu on.

Kind Regards,

Bjørn

[jtredez]

Hi,

Unfortunately I have not managed to reproduce the error (maybe it is not). I have flashed 10 time the device without an error, exept a timemout durring the connection because it's return into slow mode.

Thank you for your time.