92HD65C Datasheet, PDF (19/268 Pages) Integrated Device Technology – SIX CHANNEL HD AUDIO CODECS

92HD65C
SIX CHANNEL HD AUDIO CODEC WITH DUAL CAPLESS HEADPHONE AMPLIFIERS
2.14. Vendor Specific Function Group Power States D4/D5
The codec introduces vendor specific power states. A vendor defined verb is added to the Audio
Function Group that combines multiple vendor specific power control bits into logical power states
for use by the audio driver. The 2 states defined offer lower power than the 5 existing states defined
in the HD Audio specification and HDA015-B. The Vendor Specific D4 state provides lower digital
power consumption relative to D3cold by disabling HD Audio link responses. Vendor specific D5 fur-
ther reduces power consumption on the digital supply by turning off GPIO drivers, and reduces ana-
log power consumption by turning off all analog circuitry except for reset circuits.
States D4/D5 are not entered until D3cold has been requested so are actually D3cold options rather
than true, independent, power states. Software can pre-program the D4 or D5 state as a re-definition
of how the part will behave when the D3cold power state is requested or software may enter D3cold,
then set the D4 or D5 before performing the power state get command. The preferred method is to
request D3cold, then select D4 or D5 as desired.This will reduce the severity of pops encountered
when entering D4 or D5.
Both power states require a link reset or removal of DVDD to exit.
The CODEC may pop when using these verbs and transition times to an active state (D1 or D0 for
example) may take several seconds.
2.15. Vendor Specific Function Group Power State “D5 Kill”
Vendor specific “D5 Kill” places the device in a low power, non responsive, state that is intended to
disable the CODEC when, for security reasons, it is desired that no audio playback or recording take
place.
State “D5 Kill” is not entered until D3cold has been requested. Software pre-programs both the D4
and D5 state request bits (D4 and D5 = 1) then request D3cold. After responding to the Function
Group Power State Get verb (needed to enter D3cold), the CODEC will no longer respond to any link
activity. The only way to exit this state is to remove power (Power on reset will set the power state to
D3.)
“D5 Kill” is identical to vendor specific D5 with the exception that the CODEC will only exit this state
when power is removed.
2.16. Low-voltage HDA Signaling
The codec is compatible with 3.3V HDA bus signaling.
2.17. Multi-channel capture
The capability to assign multiple ADC Converters to the same stream is supported to meet the
microphone array requirements of Vista and future operating systems. Single converter streams are
still supported this is done by assigning unique non zero Stream IDs to each converter. All capture
devices (ADCs 0 and 1) may be used to create a multi-channel input stream. There are no restric-
tions regarding digital microphones.
The ADC Converters can be associated with a single stream as long the sample rate and the bits per
sample are the same. The assignment of converter to channel is done using the “CnvtrID” widget
and is restricted to even values. The ADC converters will always put out a stereo sample and there-
fore require 2 channels per converter.
IDT CONFIDENTIAL
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92HD65C