bt_set_static_random_bd_addr not random enough

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cross mob
Anonymous
Not applicable

Hello,

The random addresses generated by bt_set_static_random_bd_addr are not random enough. When doing my production tests (7boards at a time), I always have duplicates (within just 7 boards).

Any suggestion?

If not, is it legit to *distribute* devices programmed with the address generated by the SDK : "20736A1****"? Or in this case do I need to register a Comapny ID to the BT council? (I want to avoid this)

Kind regards,

Arthur

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1 Solution
JacobT_81
Employee
Employee
250 replies posted 100 replies posted 50 replies posted

I dug into this one a little bit and I found that our random number generator is a HW block introducing actual entropy into the API. Not pseudo-random as I had said before.

Additionally, I found that you may prevent possible duplicate numbers by postponing your call to the random generator (set random addr) to as late a time as possible in your firmware. Issues could present if the HW RNG doesn't have enough time to warm up.

Jacob

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