Cirrus Logic CS8421 - Manual (Page 6)

6 DS641F6
CS8421
Pin Name # Pin Description
XTO 1 Crystal Out (Output) - Crystal output for Master clock. See “Master Clock” on page 20 .
XTI 2
Crystal/Oscillator In (Input) - Crystal or digital clock input for Master clock. See “Master Clock”
on page 20 .
VD 3 Digital Power (Input) - Digital core power supply. Typically +2.5 V.
GND 4 Ground (Input) - Ground for I/O and core logic.
RST 5
Reset (Input) - When RST is low, the CS8421 enters a low-power mode and all internal states are
reset. On initial power-up, RST must be held low until the power supply is stable and all input
clocks are stable in frequency and phase.
BYPASS 6
Sample Rate Converter Bypass (Input) - When BYPASS is high, the sample rate converter will
be bypassed, and any data input through the serial audio input port will be directly output on the
serial audio output port. When BYPASS is low, the sample rate converter will operate normally.
ILRCK 7
Serial Audio Input Left/Right Clock (Input/Output) - Word-rate clock for the audio data on the
SDIN pin.
ISCLK 8 Serial Audio Bit Clock (Input/Output) - Serial-bit clock for audio data on the SDIN pin.
SDIN 9 Serial Audio Input Data Port (Input) - Audio data serial input pin.
MCLK_OUT 10
Master Clock Output (Output) - Buffered and level-shifted output for Master clock. If MCLK_OUT
is not required, this pin should be pulled high through a 47 k
 resistor to turn the output off. See
“Master Clock” on page 20 .
TDM_IN 11
Serial Audio TDM Input (Input) - Time Division Multiplexing serial audio data input. Grounded
when not used. See
“Time Division Multiplexing (TDM) Mode” on page 21 .
SDOUT 12
Serial Audio Output Data Port (Output) - Audio data serial output pin. Optionally, this pin may be
pulled low through a 47-k
 resistor, but must not be pulled high.
OSCLK 13 Serial Audio Bit Clock (Input/Output) - Serial-bit clock for audio data on the SDOUT pin.
OLRCK 14
Serial Audio Input Left/Right Clock (Input/Output) - Word-rate clock for the audio data on the
SDOUT pin.
MS_SEL 15
Master/Slave Select (Input) - Used to select Master or Slave for the input and output serial audio
ports at startup and reset. See
Table 1 on page 18 for settings.
GND 16 Ground (Input) - Ground for I/O and core logic.
VL 17 Logic Power (Input) - Input/Output power supply. Typically +3.3 V or +5.0 V.
SAOF 18
Serial Audio Output Format Select (Input) - Used to select the serial audio output format at
startup and reset. See
Table 3 on page 18 for format settings.
SAIF 19
Serial Audio Input Format Select (Input) - Used to select the serial audio input format at startup
and reset. See
Table 2 on page 18 for format settings.
SRC_UNLOCK 20
SRC Unlock Indicator (Output) - Indicates when the SRC is unlocked. See “SRC Locking and
Varispeed” on page 19 .