Where does the MAC address come from?

[Dan Danknick]

My project has moved off the devboard and onto prototype PCBAs. I notice that they all seem to have unique MAC IDs on the air! I'm not complaining (one less thing to worry about) but where does that MAC ID come from? Is it serialized in the nRF51822 chips or does nRFgo Studio somehow come up with one when I burn the Soft Device in?

Thank you, Dan

[Carles]

Hi there,

The Bluetooth address is a random number stored in a special register in flash during chip manufacturing. The SoftDevice loads this number and sets it as the default address every time it's enabled.

Regards,

Carles

[Ole Morten]

The registers in question are NRF_FICR->DEVICEADDR[0] and [1]. :-)

[koniho]

Since the MAC address is random, is there not a uniqueness guarantee? Is the MAC address editable?