NXP Semiconductors K32 L2A Series, Reference Manual, Page: 1249 / 1379

Register Offset Description
TRNG0_ENTa 40h + (a × 4h) Word a
48.1.3.3.28.2 Function
The RNG TRNG can be programmed to generate an entropy value that is readable via the
SkyBlue bus. To do this, set the TRNG0_MCTL[TRNG_ACC] bit to 1. Once the entropy
value has been generated, the TRNG0_MCTL[ENT_VAL] bit will be set to 1. At this
point, TRNG0_ENT0 through TRNG0_ENT15 may be read to retrieve the 512-bit
entropy value. Note that once TRNG0_ENT15 is read, the entropy value will be cleared
and a new value will begin generation, so it is important that TRNG0_ENT15 be read
last. These registers are readable only when TRNG0_MCTL[PRGM] = 0 (Run Mode),
TRNG0_MCTL[TRNG_ACC] = 1 (TRNG access mode) and
TRNG0_MCTL[ENT_VAL] = 1. After at most one (1) bus clock cycle of reading a valid
TRNG0_ENT15 register value, reading any TRNG0_ENT0 through TRNG0_ENT15
register would return zeroes.
48.1.3.3.28.3 Diagram
Bits 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R ENT
W
Reset
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bits 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R ENT
W
Reset
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
48.1.3.3.28.4 Fields
Field Function
31-0
ENT
Entropy Value. Will be non-zero only if TRNG0_MCTL[PRGM] = 0 Run Mode) and
TRNG0_MCTL[ENT_VAL] = 1 (Entropy Valid). The most significant bits of the entropy are read from the
lowest offset, and the least significant bits are read from the highest offset. Note that reading the highest
offset also clears the entire entropy value, and starts a new entropy generation.
Chapter 48 SA-TRNG Standalone
K32 L2A Reference Manual, Rev. 2, 01/2020
NXP Semiconductors 1249