why are the random addresses the some?

Question

hi everyone.now i am developing a project with nrf51822.i am using the PCA10000 dongle to see some information of advertising packages. i moved out and pluged in the PCA10001 many times,but the random address are the some.why?general speaking,they should be different.

Carles · Accepted Answer

Hi there, 
 By default the SD used the "Static Random" address type as defined by the Specification in GAP 10.8.1.
This means that it is a random number but static: i.e. it does not change at all, it is actually stored in flash in a special register called the FICR and loaded from there every time the SD is initialized. 
 You sound like you require a random private (non-resolvable) address, which is designed to change periodically. To do this, simply generate your own random number and use: 
 sd_ble_gap_address_set() 
 to set it. 
 Regards, 
 Carles