System Board
Input/output Controller Hub 2 (82801BA)
Chapter 2
48
Advanced Programmable Interrupt Controller
You can use the APIC, which is incorporated in the ICH2, in either single-processor or
multiprocessor systems, whereas the standard interrupt controller supports only
single-processor systems.
Real Time Clock
The RTC is 146818A-compatible, with 256 bytes of CMOS. The RTC performs two key
functions:
• Keeps track of the time
• Stores system data
The RTC operates on a 32.768KHz crystal and a separate 3V lithium battery that
provides up to seven years of protection for an unplugged system. The RTC also supports
two lockable memory ranges. By setting bits in the configuration space, you can lock two
8-byte ranges to read and write accesses. This procedure prevents unauthorized reading
of passwords or other security information. Another feature is a date alarm that allows
for a schedule wake-up event as much as 30 days in advance.
Enhanced Power Management
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 that require 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
• High-quality pseudo-differential CD input
• Mono microphone input
• Analog line-level stereo inputs for LINE IN
• Stereo line-level output
• Compliance with Microsoft’s PC’98 and PC’99 audio performance requirements
