Chapter 3 Memory Mapping Control (S12XMMCV4)
MC9S12XE-Family Reference Manual , Rev. 1.19
200
Freescale Semiconductor
EROMON and ROMON control the visibility of the Flash in the memory map for CPU or BDM (not for
XGATE). Both local and global memory maps are affected.
2
EROMON
Enables emulated Flash or ROM memory in the memory map
Write: Never
This bit is used in some modes to define the placement of the Emulated Flash or ROM (Refer to
0 Disables the emulated Flash or ROM in the memory map.
1 Enables the emulated Flash or ROM in the memory map.
1
ROMHM
FLASH or ROM only in higher Half of Memory Map
Write: Once in normal and emulation modes and anytime in special modes
0 The fixed page of Flash or ROM can be accessed in the lower half of the memory map. Accesses to
0x4000–0x7FFF will be mapped to 0x7F_4000-0x7F_7FFF in the global memory space.
1 Disables access to the Flash or ROM in the lower half of the memory map.These physical locations of the
Flash or ROM can still be accessed through the program page window. Accesses to 0x4000–0x7FFF will be
mapped to 0x14_4000-0x14_7FFF in the global memory space (external access).
0
ROMON
Enable FLASH or ROM in the memory map
Write: Once in normal and emulation modes and anytime in special modes.
This bit is used in some modes to define the placement of the ROM (Refer to
)
0 Disables the Flash or ROM from the memory map.
1 Enables the Flash or ROM in the memory map.
Table 3-12. Data Sources when CPU or BDM is Accessing Flash Area
Chip Modes
ROMON
EROMON
DATA SOURCE
(1)
1. Internal Flash means Flash resources inside the MCU are read/written.
Emulation memory means resources inside the emulator are read/written (PRU registers, flash
replacement, RAM, EEPROM and register space are always considered internal).
External application means resources residing outside the MCU are read/written.
Stretch
(2)
2. The external access stretch mechanism is part of the EBI module (refer to EBI Block Guide for details).
Normal Single Chip
X
X
Internal Flash
N
Special Single Chip
Emulation Single Chip
X
0
Emulation Memory
N
X
1
Internal Flash
Normal Expanded
0
X
External Application
Y
1
X
Internal Flash
N
Emulation Expanded
0
X
External Application
Y
1
0
Emulation Memory
N
1
1
Internal Flash
Special Test
0
X
External Application
N
1
X
Internal Flash
Table 3-11. MMCCTL1 Field Descriptions (continued)
Field
Description
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