CS4299 Datasheet, PDF (11/52 Pages) Cirrus Logic – CrystalClear SoundFusion Audio Codec 97

CS4299
Slot 2. Write operations are similar, with the regis-
ter index in Slot 1 and the write data in Slot 2 of a
SDATA_OUT frame. The function of each input
and output frame is detailed in Section 3, AC Link
Frame Definition. Individual register descriptions
are found in Section 4, Register Interface.
2.3 Sample Rate Converters
The Sample Rate Converters (SRCs) provide high
accuracy digital filters supporting sample frequen-
cies other than 48 kHz to be captured from the
CS4299 or played from the controller. AC ’97 re-
quires support for two audio rates (44.1 and
48kHz). In addition, the Intel^® I/O Controller Hub
(ICHx) specification requires support for five more
audio rates (8, 11.025, 16, 22.05, and 32). The
CS4299 supports all these rate, as shown in Table 7
on page 29.
2.4 Output Mixer
The CS4299 has two output mixers, illustrated in
Figure 8. The stereo output mixer sums together
the analog inputs to the CS4299, including the
PC_BEEP and PHONE signals, according to the
settings in the volume control registers. The stereo
output mix is sent to the LINE_OUT and
ALT_LINE_OUT pins on the CS4299. The mono
output mixer generates a monophonic sum of the
left and right channels from the stereo input mixer.
The mono output mix is sent to the MONO_OUT
output pin on the CS4299.
2.5 Input Mux
The input multiplexer controls which analog input
is sent to the ADCs. The output of the input mux is
converted to stereo 18-bit digital PCM data and
sent to the controller by means of the AC-link
SDATA_IN signal.
2.6 Volume Control
The CS4299 volume registers control analog input
levels to the input mixer and analog output levels,
including the master volume level, and the alternate
volume level. The PC_BEEP volume control uses
3 dB steps with a range of 0 dB to -45 dB attenua-
tion. All other analog volume controls use 1.5 dB
steps. The analog inputs have a mixing range of
+12 dB signal gain to -34.5 dB signal attenuation.
The analog output volume controls have from 0 dB
to -94.5 dB attenuation for LINE_OUT and from
0 dB to -46.5 dB attenuation for ALT_LINE_OUT
and MONO_OUT.
11