CS4281 Datasheet, PDF (29/36 Pages) Cirrus Logic – CrystalClear PCI Audio interface

CS4281
CrystalClear™ PCI Audio Interface
MIDIIN - MIDI Data Input
This is the serial input pin for the internal MIDI port. An internal 20 kΩ pull-up resistor will
pull MIDIIN to CVDD.
MIDIOUT - MIDI Data Output
This is the serial output pin for the internal MIDI port.
CVDD[2:1] - Core Power Supply
Core power pins. These pins must be connected to a nominal +3.3 Volts.
CGND[3:1] - Core Ground Supply
Core digital ground reference pins.
Serial Codec Interface
ABITCLK - AC-Link Bit Clock, Input
Master timing clock for serial audio data. This pin is an input which drives the timing for the
AC-Link interface, along with providing the source clock for the CS4281.
ASYNC - AC-Link Frame Sync, Output
Framing clock for serial audio data. This pin is an output which indicates the 48 kHz framing
for the AC-Link. High during slot 0 and low for slots 1 through 12. Also used to induce a
warm reset of the AC-Link when its down.
ASDOUT - AC-Link Data Out, Output
CS4281 serial data out. Provides a register interface and playback audio data path to both the
Primary and Secondary Codecs.
ARST# - AC-Link Reset, Output, Active Low
AC-Link and Codec reset pin. This pin is the logical OR of the PCI reset pin RST# and the
software controlled RSTN bit in the SPMC register. When low, forces all Codecs attached to
the AC Link into a cold reset state.
ASDIN - Primary Codec Data In, Input
Primary Codec’s serial data input to the CS4281 for register reads and capture audio data
streams. This pin is powered from the VAUX power pin to support wake-up events that drive
PME#.
ASDIN2/GPIO1 - Secondary Codec Data In, Input / General Purpose I/O Pin 1
Secondary Codec’s serial data input to the CS4281 or general purpose input, selected via the
Serial Power Management Control (SPMC) register. This pin is powered from the VAUX
power pin to support wake-up events that drive PME#. As a general purpose I/O pin, it
supports extended capability and PME# (powered from VAUX). If this pin is not used, it
should have an external resistor of 50 kΩ or greater attached to ground (not power).
CIRRUS LOGIC PRODUCT DATA SHEET
DS308PP4
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