Hd Audio Link Bus; Audio Codec - HP Compaq dc7600 MT Technical Reference Manual

Input/Output Interfaces
5.8.3 HD Audio Codec
The HD Audio Codec provides pulse code modulation (PCM) coding and decoding of audio
information as well as the selection and/or mixing of analog channels. As shown in Figure 5-13,
analog audio from an external microphone, tape, or internal CD can be selected and, if to be
recorded (saved) onto a disk drive, routed through an analog-to-digital converter (ADC). The
resulting left and right PCM record data are muxed into a time-division-multiplexed (TDM) data
stream (SD IN signal) that is routed to the audio controller. Playback (PB) audio takes the reverse
path from the audio controller to the audio codec as SD OUT data and is decoded and either
routed through an equalizer or applied directly to the digital-to-analog converter (DAC). The
codec supports simultaneous record and playback of stereo (left and right) audio. The sampling
rate used by the Sample Rate Controllers (SRC) may be set independently for the ADCs and the
DAC. The integrated analog mixer provides the computer control-console functionality handling
multiple audio inputs.
Mic Audio In
CD Audio In
Line Audio In
PC Beep In
Line Audio
Out
HP Audio
Out
NOTE:
The audio codec includes two ADCs. However, only one is
typcially used.
All audio lines represent both left and right channel information.
Figure 5-13. ALC260 HD Audio Codec Functional Block Diagram
All functions are controlled through index-addressed registers of the codec.
5-32
REC
Mux
Gain
REC
Mux
Gain
Mux/Gain
PB
Gain
PB
Gain
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Audio
Format
ADC
Audio In
w/SRC
ADC Audio In
w/SRC
HD
Audio
Interface
DAC
Audio Out
w/SRC
Technical Reference Guide
SDI
RST#
HD Audio
Link Bus
BCLK
to/from
Audio
Controller
SYNC
SDO