DFU Peripheral to Central?

[Arepa]

Hi all

Is possible have DFU in the peripheral side to update a Central app program? Is there example doing it?

I have a Peripheral (custom board nRF52 dongle) connected to a PC, and I want to update the application program in the Central side (remote battery powered) using DFU.

Is possible to do a DFU Periphera-to-Central role instead of Central-to-Peripheral?

Thanks

[Hung Bui]

Hi Arepa,

Does it have to be the remote device running in central mode when you are doing DFU ?

We currently don't have an example for that.

But please be noted that the S132 is capable of running in both central and peripheral. So there is an option that you run your device in central mode, then you send a command from the peripheral connected PC that the remote device switch to bootloader and starts as a peripheral. You then can also switch the peripheral into central mode to do DFU update.

With this solution you only need to make the DFU master part which run on the PC. (We don't have this part yet). Alternatives are you can update using a phone or from PC via nrfutil tool (if you run the dongle with connectivity firmware).

If you really have to keep the remote device in central role, then you need to implement your own bootloader. You can reuse many parts from the default bootloader, you can set up a GATT server on the central side and receive image to that server. Only difference here is the DFU master advertise, the DFU target connects instead of the other way around.

[Hung Bui]

I would need to have a little more information about your peripheral. How many peripheral do you have ? How often do you need to connect and exchange data between the peers ?

Staying in RX mode for one second consume way more data than advertising in one second, even with shortest advertising interval.

Note that when advertising, the peripheral doesn't send data all the time, the minimum normal advertising interval is 20ms and the device only stay up about 4ms to send data before it sleeps the rest of the time (16ms). As in the power calculator tool, you can easily find the average current consumption is only about 400uA compare to 7-8mA when staying in RX mode constantly.