Real-Time Clock Subsystem; Legacy I/O Controller - Intel BOXD2700DC Specification

Intel Desktop Board D2700DC 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:
• Serial IRQ interface compatible with serialized IRQ support for Conventional
PCI bus systems
• Intelligent power management, including a programmable wake-up event
interface
• Conventional PCI bus power management support
The BIOS Setup program provides configuration options for the Legacy I/O controller.
For information about
The location of the headers
22
Refer to
Figure 11, page 41