92HD66B IDT [Integrated Device Technology], 92HD66B Datasheet - Page 31

• Manufacturer Part Number: 92HD66B
• Description: FOUR CHANNEL HD AUDIO CODECS
• Manufacturer: IDT [Integrated Device Technology]

92HD66B
FOUR CHANNEL HD AUDIO CODECS WITH DUAL CAPLESS HEADPHONE AMPLIFIERS
©2011 INTEGRATED DEVICE TECHNOLOGY, INC.
2.21. Digital PC-Beep
main clock is typically 810KHZ. The threshold_high is 150 cycles (~37%) and the threshold_low is
30 cycles (~7.5%).
If BEEP_PRESENCE=1, it will be cleared until counter is lower than threshold in 1ms window and it
repeat for N times. N(1 is for 1ms) can be programmable to one among 64ms, 64ms*2, 64ms*4 and
64ms*8.
2.20.1.3. Logic control
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Once analog PCbeep is detected(BEEP_PRESENCE=1), analog pc_beep will be enabled
If in D0-D2, enabled simply means muting or un-muting beep to avoid hearing system noise on the
beep input pin but it is acceptable to turn off port amplifiers if not currently used by DACs, mixer, or
beep to save power.
If in D3, enabled means that the necessary amplifiers are turned on so that the beep signal may be
heard on all ports configured as outputs (see analog pc-beep description section above)
All needed amplifiers are enabled until BEEP_PRESENCE=0 for longer than the idle threshold
This block uses an 8-bit divider value to generate the PC beep from the 48kHz HD Audio Sync
pulse. The digital PC_Beep block generates the beep tone on all Pin Complexes that are currently
configured as outputs. The HD Audio spec states that the beep tone frequency = (48kHz HD Audio
SYNC rate) / (4*Divider), producing tones from 47 Hz to 12 kHz (logarithmic scale). Other audio
sources are disabled when digital PC_Beep is active.
It should be noted that digital PC Beep is disabled if the divider = 00h.
Phase 1: analog beep auto-routing phase in the period after digital POR, before the first rising
edge of link reset.
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Phase 2: When not in phase 1
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Once Analog PCbeep is detected(BEEP_PRESENCE=1) after 64ms delays (after POR), the
Amplifier will be turned on(port_pwd=0, port_output_en=1, there is a timing between these
two signals) and analog_beep_en=1. If BEEP_PRESENCE=0 for longer than the threshold
time, the amplifiers will be turned off to save power and prevent unwanted system noise
from being heard.
If analog beep function is disabled by driver. Analog beep auto-detect will also be disabled.
If analog beep function is enabled by driver.
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92HD66B