mc68hc912bc32 Freescale Semiconductor, Inc, mc68hc912bc32 Datasheet - Page 78

• Manufacturer Part Number: mc68hc912bc32
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Operating Modes and Resource Mapping
5.4 Mode and Resource Mapping Registers
This section describes the mode and resource mapping registers.
5.4.1 Mode Register
The mode register (MODE) controls the MCU operating mode and various configuration options. This
register is not in the map in peripheral mode.
Read: Anytime
Write: Varies from bit to bit
SMODN, MODB, MODA — Mode Select Special, B, and A Bits
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These bits show the current operating mode and reflect the status of the BKGD, MODB, and MODA
input pins at the rising edge of reset.
SMODN can be written only if SMODN = 0 (in special modes) but the first write is ignored; MODB,
MODA may be written once if SMODN = 1; anytime if SMODN = 0, except that special peripheral and
reserved modes cannot be selected.
Normal expanded narrow:
Special expanded narrow:
Special expanded wide:
Normal expanded wide:
Special single-chip:
Normal single-chip:
Reset states:
Peripheral:
Address: $000B
Read:
Write:
SMODN
Precedence
Bit 7
1
1
0
0
0
1
0
1
2
3
4
5
6
Figure 5-1. Mode Register (MODE)
M68HC12B Family Data Sheet, Rev. 9.1
Table 5-2. Mapping Precedence
MODB
6
0
1
0
1
1
0
0
MODA
5
1
1
1
1
0
0
0
FLASH EEPROM/ROM
ESTR
BDM ROM (if active)
4
1
1
1
1
1
1
1
External memory
Register space
Resource
EEPROM
RAM
IVIS
3
0
0
1
1
1
0
1
EBSWAI
2
0
0
0
0
0
0
0
Freescale Semiconductor
1
0
0
0
0
0
0
0
0
EME
Bit 0
0
0
1
1
1
0
1