MC68HC912DG128 Datasheet, PDF (76/452 Pages) Motorola, Inc – Microcontrollers

Operating Modes
Freescale Semiconductor, Inc.
Table 5-1. Mode Selection
BKGD MODB MODA
1
0
0
1
0
1
1
1
0
1
1
1
0
0
0
0
0
1
0
1
0
0
1
1
Mode
Normal Single Chip
Normal Expanded Narrow
Reserved (Forced to
Peripheral)
Normal Expanded Wide
Special Single Chip
Special Expanded Narrow
Special Peripheral
Special Expanded Wide
Port A
G.P. I/O
ADDR/DATA
—
ADDR/DATA
G.P. I/O
ADDR/DATA
ADDR/DATA
ADDR/DATA
Port B
G.P. I/O
ADDR
—
ADDR/DATA
G.P. I/O
ADDR
ADDR/DATA
ADDR/DATA
There are two basic types of operating modes:
Normal modes — some registers and bits are protected
against accidental changes.
Special modes — allow greater access to protected control
registers and bits for special purposes such as testing and
emulation.
For operation above 105°C, the MC68HC912DG128 (M temperature
range product only) is limited to single chip modes of operation.
A system development and debug feature, background debug mode
(BDM), is available in all modes. In special single-chip mode, BDM is
active immediately after reset.
5.3.1 Normal Operating Modes
These modes provide three operating configurations. Background
debugging is available in all three modes, but must first be enabled for
some operations by means of a BDM background command, then
activated.
Technical Data
76
MC68HC912DG128 — Rev 3.0
Operating Modes
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