MC68HC912BD32CFU10 FREESCALE [Freescale Semiconductor, Inc], MC68HC912BD32CFU10 Datasheet - Page 53

• Manufacturer Part Number: MC68HC912BD32CFU10
• Description: Advance Information
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Internal Resource Mapping
Register Block
Mapping
7-mode
The internal register block, RAM, Flash EEPROM and EEPROM have
default locations within the 64K byte standard address space but may be
reassigned to other locations during program execution by setting bits in
mapping registers INITRG, INITRM, and INITEE. During normal
operating modes these registers can be written once. It is advisable to
explicitly establish these resource locations during the initialization
phase of program execution, even if default values are chosen, in order
to protect the registers from inadvertent modification later.
Writes to the mapping registers go into effect between the cycle that
follows the write and the cycle after that. To assure that there are no
unintended operations, a write to one of these registers should be
followed with a NOP instruction.
If conflicts occur when mapping resources, the register block will take
precedence over the other resources; RAM, Flash EEPROM, or
EEPROM addresses occupied by the register block will not be available
for storage. When active, BDM ROM takes precedence over other
resources although a conflict between BDM ROM and register space is
not possible.
All address space not utilized by internal resources is by default external
memory.
After reset the 512 byte register block resides at location $0000 but can
be reassigned to any 2K byte boundary within the standard 64K byte
address space. Mapping of internal registers is controlled by five bits in
Freescale Semiconductor, Inc.
For More Information On This Product,
Operating Modes and Resource Mapping
Go to: www.freescale.com
Table 11
Precedence
Table 11 Mapping Precedence
1
2
3
4
5
6
shows resource mapping precedence.
BDM ROM (if active)
External Memory
Flash EEPROM
Register Space
Operating Modes and Resource Mapping
Resource
EEPROM
RAM
MC68HC912BD32 Rev 1.0
Internal Resource Mapping