K60P100M100SF2RM Datasheet, PDF (785/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Chapter 33 Random Number Generator (RNGB)
33.2.2 Seed Generation Mode
During seed generation, the RNGB adds entropy generated in the TRNG to the 256-bit
XKEY register. The PRNG algorithm executes 20,000 times sampling the entropy from
the TRNG to create an initial seed for random number generation. At the same time, the
TRNG runs simple statistical tests on its output.
When seed generation is complete, the TRNG reports the pass/fail result of the tests
through RNG_ESR. If the new seed passes the statistical tests, RNG_SR[SDN] is set,
signalling that the RNG is ready to compute secure pseudo-random data. The RNG then
transitions to random number generation mode.
33.2.3 Random Number Generation Mode
When seed generation mode completes and the output FIFO is empty, the RNG enters
this mode automatically. Random number generation mode quickly creates
computationally random data that is derived by the initial seed produced in seed
generation mode.
During random number generation, a new 160-bit random number is generated whenever
the five word output FIFO is empty. When the output FIFO contains data, the RNGB
automatically enters sleep mode, waiting for the data to be read. When the data is read,
the RNGB generates a new 160-bit word and goes back to sleep.
After generating 2²⁰ words of random data, the RNGB lets the user know that it requires
reseeding through RNG_SR and continues to generate random data until it is directed to
reseed. However, if auto-seeding is selected, the RNGB automatically completes seeding
whenever it is needed.
33.3 Memory Map/Register Definition
The following table shows the address map for the RNGB module. Detailed register
descriptions are found in the following sections.
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
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