ST STM32L4 5 Series Reference Manual page 807

RM0351
27 True Random Number Generator (RNG)
27.1 Introduction
The RNG is a true random number generator that continuously provides 32-bit entropy
samples, based on an analog noise source. It can be used by the application as a live
entropy source to build a NIST compliant Deterministic Random Bit Generator (DRBG).
The RNG true random number generator has been validated according to the German
AIS-31 standard.
27.2 RNG main features
•
The RNG delivers 32-bit true random numbers, produced by an analog entropy source
post-processed with linear-feedback shift registers (LFSR).
•
It is validated according to the AIS-31 pre-defined class PTG.2 evaluation methodology,
which is part of the German Common Criteria (CC) scheme.
•
It produces one 32-bit random samples every 42 RNG clock cycles (dedicated clock).
• It allows embedded continuous basic health tests with associated error management
–
• It can be disabled to reduce power consumption.
•
It has an AMBA AHB slave peripheral, accessible through 32-bit word single accesses
only (else an AHB bus error is generated). Warning! any write not equal to 32 bits might
corrupt the register content.
27.3 RNG functional description
27.3.1 RNG block diagram
Figure 188
Includes too low sampling clock detection and repetition count tests.
shows the RNG block diagram.
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