Intel Desktop Board DG31PR Technical Product Specification

1.6.3.2 Serial ATA Interfaces

The ICH7’s Serial ATA controller offers four independent Serial ATA ports with a

theoretical maximum transfer rate of 3 Gbits/sec per port. One device can be installed

on each port for a maximum of four Serial ATA devices. A point-to-point interface is

used for host to device connections, unlike Parallel ATA IDE which supports a

master/slave configuration and two devices per channel.

For compatibility, the underlying Serial ATA functionality is transparent to the

operating system. The Serial ATA controller can operate in both legacy and native

modes. In legacy mode, standard IDE I/O and IRQ resources are assigned (IRQ 14

and 15). In Native mode, standard PCI Conventional bus resource steering is used.

Native mode is the preferred mode for configurations using the Windows* XP

operating system.



NOTE

Many Serial ATA drives use new low-voltage power connectors and require adaptors or

power supplies equipped with low-voltage power connectors.

For more information, see:

http://www.serialata.org/

For information about Refer to

The location of the Serial ATA IDE connectors

Figure 10, page 44

1.7 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.