92hd98 Integrated Device Technology, 92hd98 Datasheet - Page 29

• Manufacturer Part Number: 92hd98
• Description: Datasheet
• Manufacturer: Integrated Device Technology

92HD98
SINGLE CHIP PC AUDIO SYSTEM, CODEC+MONO SPEAKER AMPLIFIER+CAPLESS HP+LDO
IDT CONFIDENTIAL
©2009 INTEGRATED DEVICE TECHNOLOGY, INC.
Beep activity monitoring is provided when the analog beep path is enabled and the CODEC or ampli-
fier is in a low power state (D3).
The Analog PC Beep input is sampled for 500us every 1ms. If the beep input is high or low
(>200mVpp) for at least 37% of that time, it is considered active. If it is active for less than 7.5% of
that time, it is possibly inactive. If no activity is detected for 64ms (128ms, 256ms and 512ms also
selectable for the idle threshold), then beep is considered inactive.
Phase 1: analog beep auto-routing phase in the period after application of DVDD, before the first ris-
ing edge of link reset.
Once Analog PCbeep is detected(BEEP_PRESENCE=1) after 64ms delays (after POR (power on
reset)), 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.
Phase 2: When not in phase 1
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
A flow chart of Analog PC Beep is below.
A. If analog beep function is disabled by driver.
B. If analog beep function is enabled by driver.
Analog beep auto-detect will also be disabled.
Figure 8. Analog PC Beep Active
29
V 0.91 10/10
92HD98