Real-Time Clock Subsystem; Legacy I/O Controller - Intel D425KT Technical Product Specification

Intel Desktop Board D425KT and Intel Desktop Board D425KTW Technical Product
Specification
1.6

Real-Time Clock Subsystem

A coin-cell battery (CR2032) powers the real-time clock and CMOS memory. When the
computer is not plugged into a wall socket, the battery has an estimated life of three
years. When the computer is plugged in, the standby current from the power supply
extends the life of the battery. The clock is accurate to ± 13 minutes/year at 25 ºC
with 3.3 VSB applied.
NOTE
If the battery and AC power fail, custom defaults, if previously saved, will be loaded
into CMOS RAM at power-on.
When the voltage drops below a certain level, the BIOS Setup program settings stored
in CMOS RAM (for example, the date and time) might not be accurate. Replace the
battery with an equivalent one. Figure 1 on page 13 shows the location of the battery.
1.7

Legacy I/O Controller

The Legacy I/O Controller provides the following features:
One serial port header
•
One serial port connector on the back panel
•
One parallel port connector with Extended Capabilities Port (ECP) and Enhanced
•
Parallel Port (EPP) support
Serial IRQ interface compatible with serialized IRQ support for PCI Conventional
•
bus systems
• PS/2-style keyboard and mouse ports
Intelligent power management, including a programmable wake-up event interface
•
• PCI Conventional bus power management support
The BIOS Setup program provides configuration options for the Legacy I/O controller.
For information about
The location of the serial port header
The serial port header signal mapping
22
Refer to
Figure 10, page 41
Table 11, on page 43