Freescale Semiconductor, Inc.
Operating Modes
Internal Resource Mapping
EBSWAI — External Bus Module Stop in Wait Control
This bit controls access to the external bus interface when in wait
mode. The module will delay before shutting down in wait mode to
allow for final bus activity to complete.
0 = External bus and registers continue functioning during wait
mode.
1 = External bus is shut down during wait mode.
Normal modes: write anytime; special modes: write never. Read
anytime.
EMK — Emulate Port K
In single-chip mode PORTK and DDRK are always in the map
regardless of the state of this bit.
0 = Port K and DDRK registers are in the memory map. Memory
expansion emulation is disabled and all pins are general
purpose I/O.
1 = In expanded or peripheral mode, PORTK and DDRK are
removed from the internal memory map. Removing these
registers from the map allows the user to emulate the function
of these registers externally.
Normal modes: write once; special modes: write anytime EXCEPT
the first time. Read anytime.
5.5 Internal Resource Mapping
The internal register block, RAM, 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
MC68HC912DG128 — Rev 3.0
Technical Data
Operating Modes
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