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WM8569

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PP Rev 1.1 December 2005

23

DAC DIGITAL AUDIO INTERFACE CONTROL REGISTER

Interface format is selected via the DACFMT[1:0] register bits:

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0000011

Interface Control

1:0

DACFMT

[1:0]

00

Interface Format Select:

00 : Right justified mode

01: Left justified mode

10: I

11: DSP mode A orB

In left justified, right justified or I

If this bit is set high, the expected polarity of DACLRC will be the opposite of that shown Figure 11,

Figure 12 and Figure 13. Note that if this feature is used as a means of swapping the left and right

channels, a 1 sample phase difference will be introduced. In DSP modes, the DACLRP register bit is

used to select between modes A and B.

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

In left/right/I

DACLRC Polarity (normal)

0 : Normal DACLRC polarity

1: Inverted DACLRC polarity

0000011

Interface Control

2

DACLRP

0

In DSP Mode:

0 : Mode A

1: Mode B

By default, DACLRC and DIN are sampled on the rising edge of DACBCLK and should ideally

change on the falling edge. Data sources that change DACLRC and DIN on the rising edge of

DACBCLK can be supported by setting the DACBCP register bit. Setting DACBCP to 1 inverts the

polarity of DACBCLK to the inverse of that shown in Figure 11 to Figure 17.

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0000011

Interface Control

3

DACBCP

0

DACBCLK Polarity (DSP Modes):

0: Normal BCLK polarity

1: Inverted BCLK polarity

The DACIWL[1:0] bits are used to control the input word length.

REGISTER ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0000011

Interface Control

5:4

DACIWL

[1:0]

00

Input Word Length:

00 : 16 bit data

01: 20 bit data

10: 24 bit data

11: 32 bit data

Note: 32-bit right justified mode is not supported.

In all modes, the data is signed 2's complement. The digital filters always input 24-bit data. If the

DAC is programmed to receive 16 or 20 bit data, the WM8569 pads the unused LSBs with zeros. If

the DAC is programmed into 32 bit mode, the 8 LSBs are ignored.

Note: In 24 bit I

minimum of 24 BCLKs and low for a minimum of 24 BCLKs.

A number of options are available to control how data from the Digital Audio Interface is applied to

the DAC channels.