MC68HC908KX8 Datasheet, PDF (144/310 Pages) Motorola, Inc – Microcontrollers

Configuration Register (CONFIG)
9.3 Functional Description
The configuration registers are used in the initialization of various
options and can be written once after each reset. All of the configuration
register bits are cleared during reset. Since the various options affect the
operation of the microcontroller unit (MCU), it is recommended that
these registers be written immediately after reset. The configuration
registers are located at $001E and $001F. For compatibility, a write to a
read-only memory (ROM) version of the MCU at this location will have
no effect. The configuration register may be read at anytime.
NOTE:
The CONFIG module is known as an MOR (mask option register) on a
ROM device. On a ROM device, the options are fixed at the time of
device fabrication and are neither writable nor changeable by the user.
On a FLASH device, the CONFIG registers are special registers
containing one-time writable latches after each reset. Upon a reset, the
CONFIG registers default to predetermined settings as shown in
Figure 9-1 and Figure 9-2.
Address:
Read:
Write:
Reset:
$001E
Bit 7
R
6
5
4
3
0
EXT-
EXT-
EXT-
XTALEN SLOW CLKEN
2
1
Bit 0
0
OSCENIN- SCIBD-
STOP
SRC
0
0
0
0
0
0
0
0
= Unimplemented
R
= Reserved
Figure 9-1. Configuration Register 2 (CONFIG2)
Address: $001F
Bit 7
6
5
4
3
2
1
Read:
COPRS
LVISTOP LVIRSTD LVIPWRD LVI5OR3⁽¹⁾ SSREC
Write:
STOP
Reset: 0
0
0
0
0
0
0
Other Resets: 0
0
0
0
U
0
0
1. The LVI5OR3 bit is cleared only by a power-on reset (POR).
= Unimplemented
U = Unaffected
Figure 9-2. Configuration Register 1 (CONFIG1)
Bit 0
COPD
0
0
Technical Data
144
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
Configuration Register (CONFIG)
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