MCF548x Reference Manual, Rev. 3
22-46 Freescale Semiconductor

22.11 RNG Execution Unit (RNG)

The RNG is an execution unit capable of generating 32-bit random numbers. It is designed to comply with
the FIPS-140 standard for randomness and non-determinism. A linear feedback shift register (LSFR) and
cellular automata shift register (CASR) are operated in parallel to generate pseudo-random data.

22.11.1 RNG Register Map

The registers used in the RNG are documented primarily for debug and target mode operations. If the
requires the use of the RNG when acting as an initiator, accessing these registers directly is unnecessary.
The device drivers and the on-chip controller will abstract register level access from the user.
The single RNG contains the following registers:
Reset control register
Status register
Interrupt status register
Interrupt control register

22.11.2 RNG Reset Control Register (RNGRCR)

This register, shown in Figure 22-33, contains three reset options specific to the RNG.
Figure 22-33. RNG Reset Control Register (RNGRCR)
Table 22-30 describes RNG reset control register fields.
16 DSE Data Size Error. An inconsistent value was written to the MDEU data size register:
0 Data size error enabled
1 Data size error disabled
15-0 Reserved, should be cleared.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R00000RIMISR00000000
W
Reset0000000000000000
1514131211109876543210
R0000000000000000
W
Reset0000000000000000
Reg
Addr
MBAR + 0x2E018
Table 22-29. MDIMR Field Descriptions (Continued)
Bits Name Description