18
92HDW74C1
V 1.0 03/08
SIX CHANNEL HD AUDIO CODEC, PREMIUM WLP 3/4 COMPLIANT
92HDW74C1
SIX CHANNEL HD AUDIO CODEC, PREMIUM WLP 3/4 COMPLIANT
PC AUDIO
1.4.9.1.
AFG D0
The AFG D0 state is the active state for the device. All functions are active if their power state (if they
support power management at their node level) has been set to D0.
1.4.9.2.
AFG D1
D1 is a lower power mode where all converter widgets are disabled. Analog mixer and port functions
are active.
1.4.9.3.
AFG D2
The D2 state further reduces power by disabling the mixer and port functions. The port amplifiers
and internal references remain active to keep port coupling caps charged and the system ready for a
quick resume to either the D1 or D0 state.
1.4.9.4.
AFG D3
The D3-default state is available for HD Audio compliance. All converters are shut down. Port ampli-
fiers and references are active but in a low power state to prevent pops. Resume times may be
longer than those from D2, but still very fast to meet Intel low power goals.
The traditional use for D3 was as a transitional state before power was removed (D3 cold) before the
system entered into standby, hibernate, or shut-down. To conserve power, Intel now promotes using
D3 whenever there are no active streams or other activity that requires the part to consume full
power. The system remains in S0 during this time. When a stream request or user activity requires
Input Boost
On
Off
-
Analog mixer
On
Off
-
Mixer Volumes
On
Off
Analog PC_Beep
On
Off
Digital PC_Beep
On
-
Lo Amp
On
Low Drive2
Programmable
HP Amps
On
Low Drive2
Programmable
VAG amp
On
Low Drive3
Programmable
Port Sense
On
On4
Programmable
Reference Bias generator
On
Programmable5
Reference Bandgap core
On
Programmable5
HD Audio-Link
On
On6
-
1.No DAC or ADC streams are active. Analog mixing and loop thru are supported.
2.VAG is kept active when ports are disabled or in D2/D3. Ports may be powered down using vendor specific verbs.
3.VAG is always ramped up and down gradually, except in the case of a sudden power removal. VAG is active in D2/D3 but in
a low power state.
4. BITCLK must be active and both AVDD and DVDD must be available for Port Sense to operate.
5.Vendor specific bit for Ref Top controls VAG generator, Bandgap Reference, and Reference bias generator. Place part into
D3 and power down all ports (using vendor specific verbs) before powering down Ref Top.
6.Obviously not active if BITCLK is not running (Controller in D3).
Function
D0
D11
D2
D3
vendor specific
Table 7. Function state vs. AFG power state