RE: Why does Nordic increase the BLE MAC address by one, in DFU bootloader

Andreas — Fri, 12 Feb 2016 15:44:30 GMT

Thank you for your comments. This completely clarifys this question for me. Sorry, but I was just searching for the wrong tags/words. Because of this, I didnt found RKs link. BR

RE: Why does Nordic increase the BLE MAC address by one, in DFU bootloader

Vidar Berg — Fri, 12 Feb 2016 15:17:30 GMT

This is a way of forcing the central to perform a new service discovery and/or impede it from attempting to use any previous pairings that is not available to the bootloader (no "peer data"). Incrementing the address causes the central to see it as a new device.

One example of when you would want the device to "advertise openly": Device was paired with central when it was running in "application" mode, and bootloader dfu mode was entered by by using the bootloader button instead of buttonless entry with bond sharing/peer data. In this case the bootloader would not be able to send the required required service changed indication (Core spec. 4.1, vol 3, part G, section 2.5.2 ), and the central risk using the wrong attribute handles when it starts to write to the dfu control point on DFU start. Also, the pairing info will not be available to the bootloader when the button was used.

RE: Why does Nordic increase the BLE MAC address by one, in DFU bootloader

RK — Fri, 12 Feb 2016 15:16:27 GMT

devzone.nordicsemi.com/.../