Datasheet

Operating Modes and Resource Mapping
Technical Data MC68HC912D60A — Rev. 3.1
72 Operating Modes and Resource Mapping Freescale Semiconductor
The states of the BKGD, MODB, and MODA pins are latched into these
bits on the rising edge of the reset signal.
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 MC68HC912D60A (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.
Table 5-1. Mode Selection
BKGD MODB MODA Mode Port A Port B
1 0 0 Normal Single Chip G.P. I/O G.P. I/O
1 0 1 Normal Expanded Narrow ADDR/DATA ADDR
110
Reserved (Forced to
Peripheral)
——
1 1 1 Normal Expanded Wide ADDR/DATA ADDR/DATA
0 0 0 Special Single Chip G.P. I/O G.P. I/O
0 0 1 Special Expanded Narrow ADDR/DATA ADDR
0 1 0 Special Peripheral ADDR/DATA ADDR/DATA
0 1 1 Special Expanded Wide ADDR/DATA ADDR/DATA