92HD99B Datasheet, PDF (31/225 Pages) Integrated Device Technology – SINGLE CHIP PC AUDIO SYSTEM

92HD99
SINGLE CHIP PC AUDIO SYSTEM, CODEC+SPEAKER AMPLIFIER+CAPLESS HP+LDO
2.24. Aux Audio Support
The CODEC supports an auxiliary audio mode where analog audio is supported by default after
power is supplied with the HD Audio bus disabled. In this mode, an analog input is routed to one of
several output ports depending on jack presence detection.
In addition to shutting of the CODEC BTL and headphone amplifiers when the dock output jack is
used, the BTL amplifier will be disabled when the headphone jacks are used, and the headphone
amplifiers will be disabled when not in use.
2.24.1. General conditions in Aux Audio Mode:
HD Audio Link is off (RST# is 0, active, and BitClk is 0, inactive. CODEC does not need to monitor
BitClk to enter/exit this mode but must not depend on BitClk to operate.) (Part will enter Aux Audio
Mode immediately on application of power if Aux Audio Mode is enabled as default.)
OR
HD Audio CODEC function group power state is set to D3cold and Aux Audio Mode is enabled.
(Device enters immediately on transition to D3cold and remains in Aux mode until a double AFG
reset event is received or until the next rising edge of RST#)
• HD Audio CODEC analog and digital supplies are active.
• Port A connects to the system microphone jack.
• Port B connects to the system headphone jack.
• Port C is not used
• Port D connects to the internal speakers.
• Port E is connected to the dock Line Out jack/AUX Audio out (it is an output port)
• Port F is connected to the dock Mic Input jack/AUX Audio In (it is an input port)
• The digital microphone clock is generated by the CODEC. The DMIC data is converted to PCM
and sent to the Aux Audio Module through the Aux Out port.
• The System microphone jack (Port A) is available to the auxiliary audio subsystem. Vref_Out will
be enabled when the system Mic is plugged in.
• EAPD is used to control the power state of the mixer, BTL amplifier, and headphone amplifiers.
The amplifiers are off if EAPD is held low.
• Internal circuitry will delay enabling (change power state, un-mute, etc.) the output amplifiers a
sufficient amount of time after the application of power or EAPD=1 to prevent pops.
• Internal circuitry will orchestrate power down (EAPD = 0) to prevent pops.
• EAPD must be forced low before removing power.
• No special Dock signal present for the CODEC. Only port presence detect for the dock Line Out
(port E) is used.
• ECR15b operation does not presents a problem. The CODEC will not enter Aux Audio mode
unless the function group power state is set to D3cold prior to putting the HD Audio interface into
reset (controller D3.)To prevent undesirable behavior (pops, etc.) the bus must not be placed
into reset with the clock stopped unless EAPD is forced low or D3cold has been set. The Enable
bit in the Aux Audio vendor specific verb is provided so firmware or other software can disable
Aux Audio support. The default value of this bit is determined by a bond option and may be
determined by reading the device ID. This bit only returns to its default value when a power on
reset event is generated or when programmed to that value by software.
IDT™ CONFIDENTIAL
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©2009 INTEGRATED DEVICE TECHNOLOGY, INC.
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92HD99