CS4297
CrystalClear™ SoundFusion™ Audio Codec ’97
volume level. All analog volume controls, except
PC_BEEP, implement controlled volume steps at
nominally 1.5 dB per step. PC_BEEP uses 3 dB
fers from the AC’97 Specification in a a few minor
ways. The following list captures the specification
deviations and the implementation decisions made
steps. The analog inputs allow a mixing range of to resolve ambiguities.
+12 dB of signal gain to -34.5 dB of signal attenu-
1. The rising edge of RESET# must occur at least
1.5 ms after the digital power supply DVdd reaches
90% of maximum value.
ation. The analog output volume controls allow
from 0 dB to -94.5 dB of attenuation. The
PC_BEEP input volume control allows from 0 dB
to -45 dB of attenuation.
2. The digital input voltage threshold levels are
specified as percentages of the Vdd digital power
AC’97 IMPLEMENTATION
supply and are TTL level compatible. Min V =
ih
0.4 x Vdd, Max V = 0.16 x Vdd.
The CS4297 implements an AC’97 compliant de-
sign as defined in the Intel Audio Codec 97 Speci-
fication Version 1.03. Due to certain design trade-
offs and implementation decisions, the CS4297 dif-
il
3. The delay between setting the PR4 bit to power-
ing down the AC-Link interface is implemented as
16.24 µs.
Figure 1. Mixer Diagram
DS242F5
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