Information Technology Reference
In-Depth Information
Figure 5.8
Interrupts usage shows PS/2 port mouse
5.1.12 Power management
PIIX3 has extensive power management capability permitting a system to operate in a low
power state without being powered down. In a typical desktop PC there are two states -
power on and power off. Leaving a system powered on when not in use wastes power. PIIX3
provides a fast on/off feature that creates a third state called fast off. When in the fast off
state, the system consumes less power than the power on state.
The PIIX3's power management function is based on two modes:
•
System management mode (SMM).
•
Advanced power management (APM).
Software (called SMM code) controls the transitions between the power on state and the fast
off state. PIIX3 invokes this software by generating an SMI (system management interrupt)
to the CPU (asserting the
SMI
signal). The SMM code places the system in either the power
on state or the fast off state.
5.1.13 Graphics subsystem
The 430HX incorporates the S3 ViRGE graphics device with 2 MB of graphics memory,
which has:
•
High performance 64-bit 2D/3D graphics engine.
•
RAMDAC/clock synthesiser capable of pixel rates of 135 MHz.
•
S3 streams processor, enabling the device to convert YUV formatted video data to RGB
format.
•
3D features including flat shading and texture mapping support.
•
Fast linear addressing scheme.
•
VESA (Video Electronics Standards Association) capability.
