Intel DG33BU Real-Time Clock Subsystem, Legacy I/O Controller, Serial Port Interface

Product Description

1.8Real-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.

1.9Legacy 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

•PS/2-style mouse and keyboard interfaces

•Interface for one 1.44 MB or 2.88 MB diskette drive

•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.

1.9.1Serial Port Interface

The serial port header is 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	Refer to
The location of the serial port header	Figure 10, page 42
The serial port header signal mapping	Table 13, page 44

1.9.2Diskette Drive Interface

The I/O controller supports one diskette drive. Use the BIOS Setup program to configure the diskette drive interface.

For information about	Refer to
The location of the diskette drive connector	Figure 10, page 42

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