Real-Time Clock Subsystem; Legacy I/O Controller; Serial Port - Intel BLKDQ35JO Specification

1.8

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 12 shows the location of the battery.
1.9

Legacy I/O Controller

The I/O controller provides the following features:
• One serial port header
• Serial IRQ interface compatible with serialized IRQ support for PCI systems
• Intelligent power management, including a programmable wake-up event interface
• PCI power management support
The BIOS Setup program provides configuration options for the I/O controller.
1.9.1

Serial Port

The board has one serial port header located on the component side of the board. The
serial port supports data transfers at speeds up to 115.2 kbits/sec with BIOS support.
For information about
The location of the serial port header
The signal names of the serial port header
Product Description
Refer to
Figure 11, page 45
Table 16, page 47
23