MC68HC908JW32_09 Datasheet, PDF (41/232 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Chapter 3
Configuration Registers (CONFIG)
3.1 Introduction
This section describes the configuration registers, CONFIG1 and CONFIG2. The configuration registers
enable or disable these options:
• Computer operating properly module (COP)
• COP timeout period (262,128 or 8176 CGMRCLK cycles)
• Low-voltage inhibit (LVI) module power
• LVI module reset
• LVI module in stop mode
• LVI module voltage trip point selection
• STOP instruction
• Stop mode recovery time (32 CGMXCLK cycles or 4096 CGMXCLK cycles)
• Oscillator during stop mode
Addr.
Register Name
Bit 7
6
5
4
3
Read:
$001D
Configuration Register 2
(CONFIG2)
Write:
Reset: 0
STOP_ STOP_RC
XCLKEN CLKEN
0
0
0
0
$001F
Read:
Configuration Register 1
(CONFIG1)^†
Write:
COPRS
LVISTOP LVIRSTD LVIPWRD
Reset: 0
0
0
0
0
† One-time writable register after each reset.
= Unimplemented
2
1
Bit 0
R
VREG33D URSTD
0
0
0
SSREC STOP COPD
0
0
0
Figure 3-1. CONFIG Registers Summary
3.2 Functional Description
The configuration registers are used in the initialization of various options. The configuration register
(CONFIG1) can be written once after each reset but CONFIG2 register can perform multiple write. 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.
MC68HC908JW32 Data Sheet, Rev. 6
Freescale Semiconductor
41