S912XEG384J3VA Datasheet, PDF (200/1324 Pages) Freescale Semiconductor, Inc – MC9S12XEP100 Reference Manual Covers MC9S12XE Family

Chapter 3 Memory Mapping Control (S12XMMCV4)
Table 3-11. MMCCTL1 Field Descriptions (continued)
Field
Description
2
EROMON
1
ROMHM
0
ROMON
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 Table 3-12)
0 Disables the emulated Flash or ROM in the memory map.
1 Enables the emulated Flash or ROM in the memory map.
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).
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 Table 3-12)
0 Disables the Flash or ROM from the memory map.
1 Enables the Flash or ROM in the memory map.
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.
Table 3-12. Data Sources when CPU or BDM is Accessing Flash Area
Chip Modes
ROMON
EROMON
DATA SOURCE⁽¹⁾
Stretch⁽²⁾
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
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.
2. The external access stretch mechanism is part of the EBI module (refer to EBI Block Guide for details).
MC9S12XE-Family Reference Manual Rev. 1.25
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