Random Number Generator (RNG)
6-2
Freescale Semiconductor
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
6.2
Memory Map/Register Definition
shows the address map for the RNG module. Detailed register descriptions are found in the
following section.
6.2.1
RNG Control Register (RNGCR)
Immediately following reset, the RNG begins generating entropy (random data) in its internal shift
registers. Random data is not pushed to the output FIFO until after the RNGCR[GO] bit is set. After this,
a random 32-bit word is pushed to RNGOUT every 256 cycles.
Table 6-1. RNG Block Memory Map
IPSBAR
Offset
Register
Width
(bits)
Access
Reset Value
Section/Page
0x1F_0000
RNG Control Register (RNGCR)
32
R/W
0x0000_0000
0x1F_0004
RNG Status Register (RNGSR)
32
R
0x0010_0000
0x1F_0008
RNG Entropy Register (RNGER)
32
W
0x0000_0000
0x1F_000C
RNG Output FIFO (RNGOUT)
32
R
0x0000_0000
IPSBAR
Offset:
0x1F_0000 (RNGCR)
Access: User read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
R 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
SLM
0
IM HA GO
W
CI
Reset 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 6-1. RNG Control Register (RNGCR)
Table 6-2. RNGCR Field Descriptions
Field
Description
31–5
Reserved, must be cleared.
4
SLM
Sleep mode. The RNGA can be placed in low power mode by setting this bit. When this bit is set, the oscillators are
disabled.Clearing this bit causes the RNGA to exit sleep mode. RNGOUT is not pushed while the RNGA is in sleep
mode.
0 RNGA is not in sleep mode.
1 RNGA is in sleep mode.
3
CI
Clear interrupt. Writing a 1 to this bit clears the error interrupt and RNGSR[EI]. This bit is self-clearing,
0 Do not clear error interrupt.
1 Clear error interrupt.
2
IM
Interrupt mask.
0 Error interrupt enabled.
1 Error interrupt masked.
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:MCF52234CVM60,
MCF52235CVM60
