AV2188

June 2, 2000

6-20

DIGITAL AUDIO SERIAL INTERFACE

The digital serial interface consists of 3 serial input pins, SD1, SD2, and SD3, one serial output pin, SDOUT, one

serial clock input pin, SC, and one left/right indicator input pin, SF. The data are 2’s complement MSB first

numbers. The AV2188 supports four resolutiont, which are selected either by setting the FMT[1] and FMT[0] pins

or by programming the control register CREG0[5:4] via the I

resolution. .

The SD3, SD2 and SD1 can be either 24-bit or 32-bit per frame as well as left justified, right justified or I2S. The

SDOUT only support left justified and I2S format. The AV1488 counts the number of BCK per frame to determine

whether the input is 24 or 32 bits format.

Table (1): Audio Serial Data Input Format

Format

CREG0[5]

CREG0[4]

SD1, SD2, and SD3

SDOUT

0

0

0

24-bit

24-bit

1

0

1

20-bit

2

1

0

18-bit

3

1

1

16-bit

Table (1): Audio Serial Data Input Modes

Mode

CREG0[7]

0REG0[6]

SD1, SD2, and SD3

SDOUT

0

0

0

Right Justified

Left Justified

10

1

I2S

I2S

2

1

0

Left Justified

Left Justified

3

1

1

Invalid