WM8756

Advance Information

AI Rev 1.3 October 2001

17

MODES OF OPERATION

Control of the various modes of operation for the WM8756 is either by software control over the serial interface, or by hard-

wired pin control. Selection of software or hardware mode is via the MODE pin. The following functions may be controlled

either via the serial control interface or by hard wiring of the appropriate pins.

Note : In DSD mode, the control interface is available but none of the functions will have any effect except the PDWN bit

because the DSD data by-passes the majority of the signal processing.

FUNCTION

OPTIONS

SOFTWARE CONTROL

DEFAULT VALUE

PIN 11: MODE = 0

HARDWARE CONTROL

BEHAVIOUR

PIN 11: MODE = 1

Input audio data format

Right justified

Left justified

I

DSP formats

FMT = 00 (default)

FMT = 01

FMT = 10

FMT = 11

Pin 16, 17: ML/I2S, MC/IWL = 00, 01 or 10

Not available in hardware mode

Pin 16, 17: ML/I2S, MC/IWL = 11

Not available in hardware mode

Input word length

16

20

24

32

IWL[1:0] = 00

IWL[1:0] = 01

IWL[1:0] = 10 (default)

IWL[1:0] = 11

Pin 16, 17: ML/I2S, MC/IWL = 00 (RJ)

Pin 16, 17: ML/I2S, MC/IWL = 01 (RJ)

Pin 16, 17: ML/I2S, MC/IWL = 10 (RJ)

Pin 16, 17: ML/I2S, MC/IWL = 11 (I

De-emphasis selection

On

Off

DEEMPH = 1

DEEMPH = 0 (Default)

Pin 18: MD/DM = 1

Pin 18: MD/DM = 0

Mute

On

Off

MUTE = 1

MUTE = 0 (default)

Pin 12: MUTE = 1

Pin 12: MUTE = 0

Input LRCIN polarity

Normal

Inverted

LRP = 0 (default)

LRP = 1

Not available in hardware mode,

default value set

Volume control

Lch, Rch

individually

Lch, Rch

common

ATC = 0; 0dB (default)

ATC = 1

Not available in hardware mode,

gain defaults to 0dB

Infinite zero detect

On

Off

IZD = 1

IZD = 0 (default)

Automute function controlled from MUTE pin

low = never mute

floating = automute enable

high = mute

Power down

Chip on

Chip off

PDWN = 0 (default)

PDWN = 1

Run SCKI

Stop SCKI

DAC output control

See Table 13

for all options

Default is PL[3:0] = 1001, stereo mode

Not available in hardware mode

Table 12 Control Function Summary