57
2 System Board
The Input/Output Controller Hub (82801AA)
Audio Chip
Specifications
Devices on the SMBus
The SMBus is a subset of the I
2
C
bus. It is a two-wired serial bus which runs
at a maximum speed of 100 kHz. It is used to monitor some of the hardware
functions of the system board (such as voltage levels, temperature, fan
speed, memory presence and type), both at system boot and during normal
run-time. It is controlled by the SMBus controller located in the ICH. The
following devices are connected to the SMBus:
•
LCD status panel.
•
One Serial EEPROM MaxiLife (also includes backup values of CMOS
settings).
Feature
Description
Digitized Sounds
•
16-bit and 8-bit stereo sampling from 4 kHz to 48 kHz.
•
Hardware Full Duplex Conversion.
•
16-bit software-based real-time audio
compression/decompression system.
Music Synthesizer
•
Integrated OPL3 compatible music synthesizer.
Mixer
•
MPC-3 audio mixer.
•
Input mixing sources: microphone, LINE In,
CD Audio, AUX Audio, and digitized sounds.
•
Output mixing of all audio sources to the LINE Out or
integrated PC Workstation speaker.
•
Multiple source recording and Left/Right channels balance.
Line Input
•
Input impedance: 17k
Ω
(ohms).
•
Input range: 0 to 2.83 Vpp
Line Output
•
Stereo output of 100 mW per channel with headphone
speakers (impedance 32
Ω).
•
Output impedance: 570
Ω.
•
Output range: 0 to 2.83 Vpp.
Microphone Input
•
20 dB gain preamplifier. The boost can be muted with
software.
•
32-level programmable volume control.
•
Input impedance: 600
Ω.
•
Sensitivity: 30 mVpp to 283 mVpp.
Stereo Out Jack
•
Impedance: 32
Ω.
