
MC68HC908QY/QT Family Data Sheet, Rev. 6
Freescale Semiconductor
53
Chapter 5
Configuration Register (CONFIG)
5.1 Introduction
This section describes the configuration registers (CONFIG1 and CONFIG2). The configuration registers
enable or disable the following options:
Stop mode recovery time (32
× BUSCLKX4 cycles or
4096
× BUSCLKX4 cycles)
STOP instruction
Computer operating properly module (COP)
COP reset period (COPRS): 8176
× BUSCLKX4 or 262,128 × BUSCLKX4
Low-voltage inhibit (LVI) enable and trip voltage selection
OSC option selection
IRQ pin
RST pin
Auto wakeup timeout period
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. Most 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 this register
be written immediately after reset. The configuration registers are located at $001E and $001F, and may
be read at anytime.
NOTE
The CONFIG registers are one-time writable by the user after each reset.
Upon a reset, the CONFIG registers default to predetermined settings as
Address: $001E
Bit 7
6
54
32
1
Bit 0
Read:
IRQPUD
IRQEN
R
OSCOPT1
OSCOPT0
R
RSTEN
Write:
Reset:
000
0
00
U
POR:
000
0
000
R
= Reserved
U = Unaffected
Figure 5-1. Configuration Register 2 (CONFIG2)