STA323W

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7.3 Serial Data Interface

The STA323W serial audio input was designed to interface with standard digital audio components and to

accept a number of serial data formats. The STA323W always acts as a slave when receiving audio input

from standard digital audio components. Serial data for two channels is provided using 3 input pins: left/

right clock LRCKI (pin 33), serial clock BICKI (pin 31), and serial data 1 & 2 SDI12 (pin 32).

The SAI register (Configuration Register B - 01h, Bits D3-D0) and the SAIFB register (Configuration Reg-

ister B - 01h, Bit D4) are used to specify the serial data format. The default serial data format is I2S, MSB-

First. Available formats are shown in Figure 11 and the tables that follow.

Figure 12. General Serial Input and Output Formats

For example, SAI=1110 and SAIFB=1 would specify Right-Justified 16-bit data, LSB-First.

Table 10 below lists the serial audio input formats supported by STA323W as related to BICKI = 32/48/

64fs, where the sampling rate fs = 32/44.1/48/88.2/96/176.4/192 kHz.

Table 9. First Bit Selection Table

Note: Serial input and output formats are specified distinctly.

SAIFB

Format

0

MSB-First

1

LSB-First

I

Left Justified

LRCLK

Left

Right

SCLK

SDATA

LSB

MSB

LSB

MSB

MSB

LRCLK

Left

Right

SCLK

SDATA

LSB

MSB

LSB

MSB

MSB

Right Justified

LRCLK

Left

Right

SCLK

SDATA

LSB

MSB

LSB

MSB

MSB