Datasheet

Configuration Registers (CONFIG)
Technical Data MC68HC908LJ12 — Rev. 2.1
72 Configuration Registers (CONFIG) Freescale Semiconductor
5.3 Functional Description
The configuration registers are used in the initialization of various
options. The configuration registers 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 MCU, it is recommended that
these registers be written immediately after reset. The configuration
registers are located at $001D and $001F. The configuration registers
may be read at anytime.
NOTE: The options except LVISEL[1:0] are one-time writable by the user after
each reset. The LVISEL[1:0] bits are one-time writable by the user only
after each POR (power-on reset). The CONFIG registers are not in the
FLASH memory but 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 5-2 and Figure 5-3.
Addr.Register Name Bit 7654321Bit 0
$001D
Configuration Register 2
(CONFIG2)
†
Read: 0
STOP_
IRCDIS
STOP_
XCLKEN
DIV2CLK PCEH PCEL LVISEL1 LVISEL0
Write:
Reset:0000000
††
0
††
$001F
Configuration Register 1
(CONFIG1)
†
Read:
COPRS LVISTOP LVIRSTD LVIPWRD
0
SSREC STOP COPD
Write:
Reset:00010000
† One-time writable register after each reset.
†† Reset by POR only.
= Unimplemented
Figure 5-1. CONFIG Registers Summary