Datasheet

MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
Freescale Semiconductor 91
Chapter 5
Configuration Register (CONFIG)
5.1 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 CGMXCLK 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
• Enable/disable an extra divide by 128 prescaler in timebase module
• Enable for scalable controller area network (MSCAN)
• Selectable clockout (MCLK) feature with divide by 1, 2, and 4 of the bus or crystal frequency
• Timebase clock select
5.2 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 MSCANEN and LVI5OR3 are
one-time writable by the user after each reset. These 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 5-1 and
Figure 5-2.