MC68HC908GT16_07 Datasheet, PDF (57/292 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 4
Configuration Register (CONFIG)
4.1 Introduction
This section describes the configuration registers, CONFIG1 and CONFIG2. The configuration registers
enable or disable these options:
• Stop mode recovery time (32 CGMXCLK cycles or 4096 CGMXCLK cycles)
• COP timeout period (262,128 or 8176 COPCLK cycles)
• STOP instruction
• Computer operating properly module (COP)
• Low-voltage inhibit (LVI) module control and voltage trip point selection
• Enable/disable the oscillator (OSC) during stop mode
• External clock, external crystal, or ICG clock source
4.2 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 microcontroller unit (MCU), it is recommended that these
registers be written immediately after reset. The configuration registers are located at $001E and $001F
and may be read at anytime.
NOTE
On a Flash device, the options except LVI5OR3 are one-time writable by
the user after each reset. The LVI5OR3 bit is 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 4-1 and Figure 4-2.
MC68HC908GT16 • MC68HC908GT8 • MC68HC08GT16 Data Sheet, Rev. 5.0
Freescale Semiconductor
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