STA326
7.3 Serial Data Interface
The STA326 serial audio input was designed to interface with standard digital audio components and to
accept a number of serial data formats. The STA326 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 11. General Serial Input and Output Formats
I2S
Left
Right
LRCLK
SCLK
MSB
LSB
MSB
LSB
MSB
SDATA
Left Justified
Left
Right
LRCLK
SCLK
SDATA
MSB
LSB
MSB
LSB
MSB
Right Justified
Left
Right
LRCLK
SCLK
SDATA
MSB
LSB
MSB
LSB
MSB
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 STA326 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
SAIFB
Format
MSB-First
LSB-First
0
1
Note: Serial input and output formats are specified distinctly.
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