WM8720

Production Data

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PD Rev 4.0 February 2005

10

MODES OF OPERATION

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

by hard-wired pin control. Selection of software or hardware mode is via MODE pin. The following

functions may be controlled either via the serial control interface or by hard wiring of the

appropriate pins.

FUNCTION

OPTIONS

SOFTWARE CONTROL

DEFAULT VALUE

PIN 18: MODE = 0

HARDWARE CONTROL

BEHAVIOUR

PIN 18: MODE = 1

Input audio

data format

Normal format

I

I

I

Pin 4, 5: ML/ I

00 or 01 or 10

Pin 4, 5: ML/I

Input word length

16

18

20

24

IW[1:0] = 00 (default)

IW[1:0] = 11

IW[1:0] = 01

IW[1:0] = 10

Pin 4, 5: ML/I

Pin 4, 5: ML/I

(I

Pin 4, 5: ML/I

Pin 4, 5: ML/I

De-emphasis selection

On

Off

DE = 1

DE = 0 (default)

Pin 6: MD/DM = 1

Pin 6: MD/DM = 0

Mute

On

Off

MU = 1

MU = 0 (default)

Pin 17: MUTE = 1

Pin 17: MUTE = 0

Power down control

WM8720 on

WM8720 off

Available from Pin 1: PWDN

Pin 1: PWDN = 0

Pin 1: PWDN = 1

Input LRCIN polarity

Lch/Rch = High/low

Lch/Rch = Low/high

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,

default 0dB

Infinite zero detect

On

Off

IZD = 1

IZD = 0 (default)

Operation enable (OPE)

Enabled

Disabled

OPE = 0 (default)

OPE = 1

Automute function controlled

from MUTE pin

Low = not mute

Z = automute enable

High = muted

DAC output control

See Table 11

for all options

Default is PL[3:0] = 1001,

stereo mode

Not available in hardware mode

Table 3 Control Function Summary

HARDWARE CONTROL MODES

When the MODE pin is held high the following hardware modes of operation are available.

MUTE AND AUTOMUTE OPERATION

In both hardware and software modes pin 17 (MUTE) controls selection of mute directly, and can be

used to enable and disable the automute function, or as an output of the automuted signal.

IZD (Register Bit)

AUTOMUTED

(Internal Signal)

10k

Ω

ΩΩ

Ω

MU (Register Bit)

SOFTMUTE

(Internal Signal)

MUTE

PIN

Figure 6 Mute Circuit Operation