Chapter 3 Memory Mapping Control (S12XMMCV4)
MC9S12XE-Family Reference Manual Rev. 1.19
Freescale Semiconductor
189
•
Simultaneous accesses to different resources
1
(internal, external, and peripherals) (see
)
•
Resolution of target bus access collision
•
MCU operation mode control
•
MCU security control
•
Separate memory map schemes for each master CPU, BDM and XGATE
•
ROM control bits to enable the on-chip FLASH or ROM selection
•
Port replacement registers access control
•
Generation of system reset when CPU accesses an unimplemented address (i.e., an address which
does not belong to any of the on-chip modules) in single-chip modes
3.1.3
S12X Memory Mapping
The S12X architecture implements a number of memory mapping schemes including
•
a CPU 8 MByte global map, defined using a global page (GPAGE) register and dedicated 23-bit
address load/store instructions.
•
a BDM 8 MByte global map, defined using a global page (BDMGPR) register and dedicated 23-
bit address load/store instructions.
•
a (CPU or BDM) 64 KByte local map, defined using specific resource page (RPAGE, EPAGE and
PPAGE) registers and the default instruction set. The 64 KBytes visible at any instant can be
considered as the local map accessed by the 16-bit (CPU or BDM) address.
•
The XGATE 64 Kbyte local map.
The MMC module performs translation of the different memory mapping schemes to the specific global
(physical) memory implementation.
3.1.4
Modes of Operation
This subsection lists and briefly describes all operating modes supported by the MMC.
3.1.4.1
Power Saving Modes
•
Run mode
MMC is functional during normal run mode.
•
Wait mode
MMC is functional during wait mode.
•
Stop mode
MMC is inactive during stop mode.
3.1.4.2
Functional Modes
•
Single chip modes
In normal and special single chip mode the internal memory is used. External bus is not active.
1. Resources are also called targets.
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:
S12XE
products
in
208
MAPBGA
packages
