Retrieve Access Address from the SoftDevice

[daniel_hill]

Is there any way to get the currently used access address from the softdevice? I have an application that needs to know what access address is being used. I can sort of get it every once in a while by retrieving the NRF_RADIO->BASE0 and prefix registers, but they rarely contain data. Is this accessible via some API call or other method?

 Thanks

[daniel_hill]

The address I am trying to get is not the mac address. It is the on-air access address (part of the ble preamble). To set it in raw radio mode, I use the NRF_RADIO->BASE0 and PREFIX0 registers. I can retrieve it exactly once during the first RSSI update after a new connection starts, but never after that point (they read 0x00).

[Håkon Alseth]

Sorry for misunderstanding. The access address is sent in the CONNECT_REQ packet from the master to the slave (ie: unique for each connection), and there is no API to fetch this address on the slave side. Why do you need the access address?

[daniel_hill]

Yes, I know what it is and how it's used. I want to retrieve it on the master side (nrf52 dk running as a central on S132). The registers for BAS0 and PREFIX0 that I am reading are unfortunately zeroed by the SD after each RX or TX. I was hoping there was some api to get the address being utilized for the current connection set. As I said, I can get it once during the first rssi update from the BASE0 and PREFIX0 registers, but all subsequent reads in following rssi updates or other events give values of 0x00 for both registers. 

[Håkon Alseth]

The Softdevice will reset the radio peripheral for each connection event, to ensure that it starts from a known state, so you will not be able to read out the radio content at all times.

[daniel_hill]

Is there any specific time that I can read it out? Using radio notifications or something? Is there no API to access the stored connection parameters (hop rate, access address, and crc_init) for each connection that the SD is maintaining?

[Håkon Alseth]

I am sorry, there is no APIs for accessing the data you're asking for.

[daniel_hill]

Ok. Just for future use if someone must do what I am working on, it is possible to search the sd ram using gdb and locate the memory addresses. Then create pointers to read the data out for use in the app.