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STM32L4X6 RNG validation on 80MHz AHB

ADudk
Associate

Hello,

I require RNG's functionality for one of my commercial projects. Reading through the reference manual, it is mentioned that ST has validated RNG's performance for the following clock configurations:

RNG clock: rng_clk 48MHz, rng_clk = 400kHz

AHB clock: rng_hclk = 60MHz

Now my part is configured to 80MHz for AHB.

I am definitely no expert on RNGs, but how is the AHB clock related to functionality and entropy quality of the RNG? Looking at block diagram, all of RNG's functionality related to sampling, post-processing, analog noise interface is controlled using RNG dedicated clock.

So my questions are:

How is entropy quality related to AHB clock?

Do I need to re-validate the RNG if I want to use it at 80MHz AHB clock?

Why is it validated at a frequency of 60MHz if it is a 80MHz part?

Any other comments/suggestions related RNG, validation, NIST etc are welcome!

Thank you!

1 REPLY 1
STOne-32
ST Employee

Dear gentleman,

There is no impact of AHB Clock ( digital Sampling Frequency) . Entropy quality depends only on the RNG clock . Entropy level is better when RNG clock is the lowest.

Cheers,

STOne-32.