2 System Board

The Input/Output Controller Hub 2 (82801BA)

Timer/Counter Block The timer/counter block contains three counters that are equivalent in function to those found in one 82C54 programmable interval counter/timer. These three counters are combined to provide the system timer function, and speaker tone. The 14.318 MHz oscillator input provides the clock source for these three counters.

Advanced Programmable Interrupt Controller

Real Time Clock

Enhanced Power

Management

Incorporated in the ICH2, the APIC can be used in either single-processor or multi-processor systems, while the standard interrupt controller supports only single-processor systems.

The RTC is 146818A-compatible, with 256 bytes of CMOS. The RTC performs two key functions: keeping track of the time of day and storing system data.

The RTC operates on a 32.768 kHz crystal and a separate 3V lithium battery that provides up to 7 years of protection for an unplugged system. It also supports two lockable memory ranges. By setting bits in the configuration space, two 8-byte ranges can be locked to read and write accesses. This prevents unauthorized reading of passwords or other security information. Another feature is a date alarm allowing for a schedule wake-up event up to 30 days in advance.

The ICH2’s power management functions include enhanced clock control, local and global monitoring support for 14 individual devices, and various low-power (suspend) states. A hardware-based thermal management circuit permits software-independent entry points for low-power states.

The ICH2 includes full support for the Advanced Configuration and Power Interface (ACPI) specifications.

Crystal CS4299 Integrated PCI Audio

Based on the earlier Crystal audio controller, the CS4299 extends these features to include, among many other enhancements, PC’98 and PC’99 compliancy for multimedia desktops requiring high quality audio.

Features of the CS4299 include:

•AC’97 2.1 compatibility

•Industry leading mixed signal technology

•20-bit stereo digital-to-analog converter and 18-bit analog-to-digital converter

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