Manual
CS4299-BQ
11
tain the read data in its Slot 2. Write operations are
similar, with the register 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 Section3, ACLink Frame Definition. Individual
register descriptions are found in Section4, Regis-
ter Interface.
2.3 Sample Rate Converters
The Sample Rate Converters (SRCs) provide high
accuracy digital filters supporting sample frequen-
cies other than 48kHz 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 Table7
on page29.
2.4 Output Mixer
The CS4299-BQ has two output mixers, illustrated
in Figure8. The stereo output mixer sums together
the analog inputs to the CS4299-BQ, 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-BQ. 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-BQ.
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-BQ 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 con-
trol uses 3dB steps with a range of 0dB to -45dB
attenuation. All other analog volume controls use
1.5dB steps. The analog inputs have a mixing
range of +12dB signal gain to -34.5dB signal at-
tenuation. The analog output volume controls have
from 0dB to -94.5dB attenuation for LINE_OUT
and from 0dB to -46.5dB attenuation for
ALT_LINE_OUT and MONO_OUT.
DS319-BQPP2 11
CS4299-BQ