nRF52840 SDK16 - Advertising Device's Address (MAC address)

[Nikosant03]

Hi everyone,

When I am scanning the advertising packets of nRF52840 peripheral, I see that Device's address is type of Random Static. 

1. The Static Random Address is a randomly generated address and is preprogrammed before the device is shipped? 

2. If the user do not change the device address, it will remain the same until the end of life time of the product or it is possible to change in a random time?

In general I want the central to be connected only with a specific peripheral. What is the safest way of doing that? Is it by reading the MAC address?

Thanks in advance

Nick

[haakonsh]

1. The Static Random Address is a randomly generated address and is preprogrammed before the device is shipped?

 It is in fact the DEVICEADDR[n], randomly generated and stored in FICR in production. It is used by the SDK by default, but you can use your own randomly generated address as well. 

 

2. If the user do not change the device address, it will remain the same until the end of life time of the product or it is possible to change in a random time?

 You can change it, but be careful of what dependencies you create on your product ecosystem. If your devices, or someone else's device who interface with your device, use the BLE address as the filter during scanning it might cause you trouble if you change your BLE address. You can ofc filter on device name, UUIDs, manufacturer ID, etc. 

You can also change from Random Static to a Random Private address if you want. There's nothing in the spec that prevents you, but it will require that you re-start the SoftDevice/terminate any ongoing connections. 

[Nikosant03]

Thank you from your responce Haakonsh

haakonsh said:

It is in fact the DEVICEADDR[n], randomly generated and stored in FICR in production

Is there any case the device address asigned during production to be changed radomly by the SDK/soft device or it remains the same during the life cycle of the product? I want to ensure that the MAC address won't change during the life cycle of the product.

[haakonsh]

Nothing in FICR will change during the lifetime of the product. Our examples use the address in FICR, if you do not explicitly use another address you won't have to worry about. 

[Nikosant03]

Thank you for your support haakonsh!!