CS4297 Datasheet, PDF (40/46 Pages) Cirrus Logic – CrystalClear SoundFusion Audio Codec 97

CS4297
CrystalClear™ SoundFusion™ Audio Codec ’97
SDATA_OUT - AC-link Serial Data Input Stream to AC’97, Input
This input signal transmits the control information and digital audio output streams to be sent
to the DACs. The data is clocked into the CS4297 on the falling edge of BIT_CLK. A series
terminating resistor of 47 Ω should be connected on this signal close to the device driving the
input.
SDATA_IN - AC-link Serial Data Output Stream from AC’97, Output
This output signal transmits the status information and digital audio input streams from the
ADCs. The data is clocked out of the CS4297 on the rising edge of BIT_CLK. (See the
Digital Hardware Description section). A series terminating resistor of 47 Ω should be
connected on this signal as close to the CS4297 as possible.
XTL_IN - Crystal Input
This pin accepts either a crystal, with the other pin attached to XTL_OUT, or an external
CMOS clock. XTL_IN must have a crystal or clock source attached for proper operation. The
crystal frequency must be 24.576 MHz and designed for fundamental mode, parallel resonance
operation.
XTL_OUT - Crystal Output
This pin is used for a crystal placed between this pin and XLT_IN. If an external clock is used
on XTL_IN, this pin must be left floating with no traces or components connected to it.
Analog I/O Pins
PC_BEEP - Analog Mono Source, Input
This signal is intended to be used as an internal PC BEEP connection to the audio subsystem.
This source is NOT input to the Stereo-to-Mono mixer. The maximum allowable input is
1 V_RMS (sinusoidal). This input is internally biased at the Vrefout voltage reference and
requires AC coupling to external circuitry. If this input is not used, it should be connected to
the Vrefout pin or AC coupled to Analog ground.
PHONE - Analog Mono Source, Input
This signal is intended to be used as a Voice Modem connection to the audio subsystem. This
source is NOT input to the Stereo-to-Mono mixer. The maximum allowable input is 1 V_RMS
(sinusoidal). This input is internally biased at the Vrefout voltage reference and requires AC
coupling to external circuitry. If this input is not used, it should be connected to the Vrefout pin
or AC coupled to Analog ground.
MIC1 - Analog Mono Source, Input
This analog input is monophonic source to the analog output mixer. It is intended to be used as
a desktop microphone connection to the audio subsystem. This input is MUX selectable to the
input mixer with the MIC2 input source. The maximum allowable input is 1 V_RMS (sinusoidal).
This input is internally biased at the Vrefout voltage reference and requires AC coupling to
external circuitry. If this input is not used, it should be AC coupled to Analog ground.
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