92HD91 Datasheet, PDF (44/298 Pages) Integrated Device Technology – SINGLE CHIP PC AUDIO SYSTEM

92HD91
SINGLE CHIP PC AUDIO SYSTEM, CODEC+SPEAKER AMPLIFIER+CAPLESS HP+LDO
2.26.10. Class-D BTL Issues
While in Aux Audio mode the HD Audio bus clock (BitClk) is not available. The Class-D controller
requires a very high speed clock to operate and an internal clock must be provided. In Aux Audio
mode, the actual frequency used by the Class-D controller and its associated ADC will not be exact
since an external reference will not be available.The performance characteristics in Aux Audio Mode
will be degraded compared to the normal operating mode characteristics specified elsewhere in this
document.
2.26.11. Firmware/Software Requirements:
The reconfiguration outlined in this chapter is autonomous (without the help of firmware or OS
driver.)
This autonomous mode does not interfere with normal operation.
If it is desirable to stop the HD Audio bus while the CODEC is in D3 under OS control per DCN
HDA015-B, no action is required. The CODEC will not enter Aux Audio Mode unless placed in
D3cold.
2.27. Microphone Mute Input
Available on silicon revision WB and beyond.
The 92HD91 supports a microphone mute input. An external switch or other circuit may directly
mute the CODEC without relying on software control. This is a most helpful feature for allowing the
end user to conveniently enforce privacy since it bypasses the record gain/mute functions typically
controlled by software. While recording is muted, any active stream will receive digital silence.
IDT™ CONFIDENTIAL
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