WM8778SEDSSLASHR datasheet(23/50 Pages) WOLFSON

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WM8778

PP Rev 1.7 June 2004

HARDWARE MODE

Hardware mode is selected by applying a midrail voltage to the MODE pin, or by leaving it floating.

The circuit detects this condition and enables hardware mode. This allows limited control of the

internal functions using the three inputs CE, CL and DI. The table below gives a summary of the use

of each pin in hardware mode.

PIN NAME

FUNCTION

DESCRIPTION

CE\I2S

Interface Mode select

0 : Right Justified

1 : I

CL\IWL

Interface Wordlength select

0 : 20 bit (RJ), 16 bit (I

2S)

1 : 24 bit

DI\DEEMPH

De-emphasis on/off

0 : De-emphasis disabled

1 : De-emphasis enabled

Table 12 Hardware Mode Functions

CONTROL INTERFACE REGISTERS

DIGITAL AUDIO INTERFACE CONTROL REGISTER

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

BIT

LABEL

DEFAULT

DESCRIPTION

R10 (0Ah)

0001010

DAC Interface Control

1:0

DACFMT

[1:0]

R11 (0Bh)

0001011

ADC Interface Control

1:0

ADCFMT

[1:0]

Interface format Select

00 : right justified mode

01: left justified mode

10: I

2S mode

11: DSP (early or late) mode

In left justified, right justified or I

2S modes, the LRP register bit controls the polarity of

ADCLRC/DACLRC. If this bit is set high, the expected polarity of ADCLRC/DACLRC will be the

opposite of that shown Figure 12, Figure 13, etc. 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 LRP register bit is used to select between early and late modes.

BIT

LABEL

DEFAULT

DESCRIPTION

R10 (0Ah)

0001010

DAC Interface Control

DACLRP

R11 (0Bh)

0001011

ADC Interface Control

ADCLRP

In left/right/ I

2S modes:

ADCLRC/DACLRC Polarity (normal)

0 : normal ADCLRC/DACLRC

polarity

1: inverted ADCLRC/DACLRC

polarity

In DSP mode:

0 : Early DSP mode

1: Late DSP mode

By default, ADCLRC, DACLRC and DIN are sampled on the rising edge of ADCBCLK and

DACBCLK

and should ideally change on the falling edge. Data sources that change

ADCLRC/DACLRC and DIN on the rising edge of ADCBCLK/DACBCLK can be supported by setting

the BCP register bit. Setting BCP to 1 inverts the polarity of BCLK to the inverse of that shown in

Figure 12, Figure 13, etc.

BIT

LABEL

DEFAULT

DESCRIPTION

R10 (0Ah)

0001010

DAC Interface Control

DACBCP

R11 (0Bh)

0001011

ADC Interface Control

ADCBCP

BCLK Polarity (DSP modes)

0 : normal BCLK polarity

1: inverted BCLK polarity

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