mc68hc912bd32 Freescale Semiconductor, Inc, mc68hc912bd32 Datasheet - Page 52

• Manufacturer Part Number: mc68hc912bd32
• Description: 16-bit Device Composed Of Standard On-chip Peripherals
• Manufacturer: Freescale Semiconductor, Inc

Operating Modes and Resource Mapping
MC68HC912BD32 Rev 1.0
IVIS — Internal Visibility
EBSWAI — External Bus Module Stop in Wait Control
EME — Emulate Port E
Normal modes: write once; Special modes: write anytime, read
anytime.
This bit determines whether internal ADDR/DATA, R/W, and LSTRB
signals can be seen on the bus during accesses to internal locations.
In special expanded narrow mode, it is possible to configure the MCU
to show internal accesses on an external 16-bit bus. The IVIS control
bit must be set to 1. When the system is configured this way, visible
internal accesses are shown as if the MCU was configured for
expanded wide mode but normal external accesses operate as if the
bus was in narrow mode. In normal expanded narrow mode, internal
visibility is not allowed and IVIS is ignored.
Normal modes: write once; Special modes: write anytime EXCEPT
the first time. Read anytime.
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.
Removing the registers from the map allows the user to emulate the
function of these registers externally. In single-chip mode PORTE and
DDRE are always in the map regardless of the state of this bit.
Normal modes: write once; special modes: write anytime EXCEPT
the first time. Read anytime.
Freescale Semiconductor, Inc.
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0 = No visibility of internal bus operations on external bus
1 = Internal bus operations are visible on external bus
0 = External bus and registers continue functioning during Wait
1 = External bus is shut down during Wait mode.
0 = PORTE and DDRE are in the memory map.
1 = PORTE and DDRE are removed from the internal memory map
Operating Modes and Resource Mapping
mode.
(expanded mode).
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6-mode