Overview, Three-wire serial input/output audio port – Cirrus Logic CS8422 User Manual
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DS692F2
CS8422
4. OVERVIEW
The CS8422 is a 24-bit, high performance, monolithic CMOS stereo asynchronous sample rate converter with inte-
grated digital audio interface receiver that decodes audio data according to EIAJ CP1201, IEC-60958, AES3, and
S/PDIF interface standards.
Audio data is input through either a 3-wire serial audio port or the AES3-compatible digital interface receiver. Audio
data is output through one of two 3-wire serial audio output ports. The serial audio ports are capable of 24, 20, 18,
or 16-bit word lengths. Data in to the digital interface receiver can be up to 24-bit. Input and output data can be com-
pletely asynchronous, synchronous to an external data clock through XTI, or synchronous to the master clock re-
covered from the incoming S/PDIF or AES3 data.
CS8422 can be controlled either in Software Mode or in a stand-alone Hardware Mode. In Software Mode, the user
can control the device through either a SPI or I²C control port.
Target applications include digital recording systems (DVD-R/RW, CD-R/RW, PVR, DAT, MD, and VTR), digital mix-
ing consoles, high quality D/A, effects processors, and computer audio systems.
and
show typical connections to the CS8422.
5. THREE-WIRE SERIAL INPUT/OUTPUT AUDIO PORT
The CS8422 provides two independent 3-wire serial audio output ports, and a 3-wire serial audio input (only avail-
able in Software Mode). The interface format should be chosen to suit the attached device either through the control
port in Software Mode, or through the MS_SEL and SAOF pins in Hardware Mode. The following parameters are
adjustable:
Hardware Mode
•
Master or slave mode operation
•
Master-mode MCLK-to-OLRCK (OLRCK1 and OLRCK2) ratios: 128, 256, and 512
•
Audio data resolution of 16, 20, or 24-bits
•
Left-Justified, I²S, or Right-Justified serial data formats
•
Multi-channel TDM serial audio format (Serial Audio Output 1 only)
Software Mode
•
Master or slave mode operation
•
Master-mode MCLK-to-ILRCK and MCLK-to-OLRCK (OLRCK1 and OLRCK2) ratios: 64, 128, 192, 256,
384, 512, 768, and 1024
•
Audio data resolution of 16, 18, 20, or 24-bits
•
Left-Justified, I²S, or Right-Justified serial data formats
•
Multi-channel TDM serial audio format
•
AES3 Direct Output format
,
, and
show the standard input/output formats available. The TDM serial audio format is de-
scribed in
. For more information about serial audio formats, refer to the Cirrus Logic ap-
plications note AN282, “The 2-Channel Serial Audio Interface: A Tutorial”, available at