Accessing the TRNG on STM32U575I-EV Eval Board

[ST64]

Can the internal TRNG peripheral of the STM32U5MCU be accessed on the STM32U575I-EV eval board?

[TDK]

You can access the RNG peripheral, which in some publications is called the TRNG. There is no separate TRNG peripheral.

[ST64]

Thank you for the response.   I realized the TRNG peripheral is integral to the STM32U5.   How do I configure and use it?

Looking for clues, the spec sheet for the eval board does not mention the TRNG feature.   The user manual for the eval board makes no mention of the TRNG..   The schematics for the eval board do not show the TRNG peripheral or where its needed input signals might be obtained -- the brief documentation on the HASH and TRNG peripherals make mention of AHB_CLK and an RNG_CLK that have to be configured for the TRNG to work.   Eval board program examples also do cover the TRNG.  I have looked elsewhere, such as for the NUCLEO board.   Example firmware show a couple of GPIO assignments then installing jumpers to assigned pins on the breakout header on the NUCLEO board to get the peripheral up and running.

[STOne-32]

Hi @ST64 ,

You can checkout the reference manual here STM32U5 Series Arm<Sup>®</Sup>-based 32-bit MCUs - Reference manual   , starting from Page 1895, Section 48 True random number generator (RNG) on how to configure and also the architecture.   @CMYL may help you for certifications matter if required .

Cheers,

STOne-32.

[Frantz LEFRERE]

hello @ST64 

in addition of @STOne-32 's info , TRNG could be used thanks HAL and you have code example in the STM32CubeU5
https://www.st.com/en/embedded-software/stm32cubeu5.html

STM32Cube_FW_U5_V1.4.0\Projects\NUCLEO-U575ZI-Q\Examples\RNG

Best regards,

Frantz 

[CMYL]

Hello @ST64 

Thanks Frantz and @STOne-32.

The examples suggested by Frantz show how to extract True random data using HAL.

In addition, if your request is NIST or AIS-31 certification, please refer to the AN4230. It explains the certification process and howto evaluate the entropy using NIST Test suites. Introduction to random number generation validation using the NIST statistical test suite for STM32 MCUs and MPUs - Application note

Note: The STM32U585/575 Series are already NIST TRNG certified (True RNG, Entropy source validation). It is published by NIST in this link Cryptographic Module Validation Program | CSRC (nist.gov) , customer can rely on this certification for his product development. 

Best Regards