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System Control Module (SCM)
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
13-6
Freescale Semiconductor
The SRAM modules are configured through the RAMBAR shown in
.
•
RAMBAR specifies the base address of the SRAM.
•
All undefined bits are reserved. These bits are ignored during writes to the RAMBAR and return
zeros when read.
•
The back door enable bit, RAMBAR[BDE], is cleared at reset, disabling the module access to the
SRAM.
NOTE
The RAMBAR default value of 0x0000_0000 is invalid. The RAMBAR
located in the processor’s CPU space must be initialized with the valid bit
set before the CPU (or modules) can access the on-chip SRAM (see
Chapter 11, “Static RAM (SRAM),”
for more information.
For details on the processor's view of the local SRAM memories, see
13.5.3
Core Reset Status Register (CRSR)
The CRSR contains a bit that indicates the reset source to the CPU. When the EXT bit (bit 7) reads as 1,
an external device driving RSTI has caused the most recent reset. The CRSR is updated by the control logic
when the reset is complete. Only one bit is set at a time in the CRSR. The register reflects the cause of the
most recent reset. To clear a bit, a logic 1 must be written to the bit location; writing a zero has no effect.
Unused bits are reserved and should not be written.
NOTE
The reset status register (RSR) in the reset controller module provides
indication of all reset sources except the core watchdog timer (see
Chapter 10, “Reset Controller Module”
).
IPSBAR
Offset: 0x0010 (CRSR)
Access: read/write
7
6
5
4
3
2
1
0
R
EXT
0
0
0
0
0
0
0
W
Reset:
See Note
0
0
0
0
0
0
0
Note: The reset value of EXT depend on the last reset source. All other bits are initialized to zero.
Figure 13-3. Core Reset Status Register (CRSR)
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