Reading just one bit wrong in the device address on FICR (NRF_FICR->DEVICEADDR[1])

[nemunoz]

Hi to everyone!

I've been testing the Bluetooth on the nRF52832 DK board with some of the examples and I have saved the mac address (obtained from my smartphone).

In other project I'm just tring to get this mac address from FICR (NRF_FICR->DEVICEADDR[1:0]). Every value fits with the saved mac excepts the bit 15 from DEVICEADDR[1].

I mean, in the phone I see the next mac:

FX:XX:XX:XX:XX:XX

And, If I use NRF_FICR->DEVICEADDR, I get:

7X:XX:XX:XX:XX:XX

(X are to hide my real mac, but every value are equal to each other). The only difference is the first bit, where this bit is 1 when I use the bluetooth with the phone and 0 if I read the internal register. The remaining bits are the same.

I know that bits [31:16] from DEVICEADDR[1] are not used, but the bit 15 is the first bit used and I don't know why I get this value changed!

Why is happening this?

Did I read the register wrong?

Thanks in advance!

[RK]

static BLE addresses on the air are required to have the top two bits set to 1. So when used for the MAC address the value read from the register is adjusted to conform to the standard by setting the top two bits to 1. The register is really just a base from which the address is derived.