MC912DG128ACPVE Datasheet, PDF (84/478 Pages) Freescale Semiconductor, Inc – Upward compatible with M68HC11 instruction set

Operating Modes
Freescale Semiconductor, Inc.
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 the
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.
EME — Emulate Port E
In single-chip mode PORTE and DDRE are always in the map
regardless of the state of this bit.
0 = PORTE and DDRE are in the memory map.
1 = If in an expanded mode, PORTE and DDRE are removed from
the internal memory map. Removing the 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.
5.4 Background Debug Mode
Background debug mode (BDM) is an auxiliary operating mode that is
used for system development. BDM is implemented in on-chip hardware
and provides a full set of debug operations. Some BDM commands can
be executed while the CPU is operating normally. Other BDM
commands are firmware based, and require the BDM firmware to be
enabled and active for execution.
In special single-chip mode, BDM is enabled and active immediately out
of reset. BDM is available in all other operating modes, but must be
enabled before it can be activated. BDM should not be used in special
peripheral mode because of potential bus conflicts.
Technical Data
84
MC68HC912DT128A — Rev 4.0
Operating Modes
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