WM8716

Production Data

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PD, Rev 4.2,August 2008

12

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.

HARDWARE CONTROL MODES

When the MODE pin is held ‘low’ the following hardware modes of operation are available. In

Hardware differential mode or 8X mode some of these modes/control words are altered or

unavailable.

DE-EMPHASIS CONTROL

MDDM1

PIN 27

MCDMO

PIN 26

DE-EMPHASIS

L

L

Off

L

H

48kHz

H

L

44.1kHz

H

H

32kHz

Table 2 De-Emphasis Control

AUDIO INPUT FORMAT

CSBIIS

PIN 28

CSBIWO

PIN 23

DATA FORMAT

L

L

16 bit normal right justified

L

H

20 bit normal right justified

H

L

H

H

Table 3 Audio Input Format

SOFT MUTE

MUTEB

PIN 25

FUNCTION

L

Mute On (no output)

Z

Automute

H

Mute Off (normal operation)

Table 4 Soft Mute

A logic low on the MUTEB pin will cause the attenuation to ramp to infinite attenuation at a rate of

128/fs seconds per 0.5dB step. Setting MUTEB high will cause the attenuation to ramp back to its

previous value.

Leaving MUTEB undriven allows operation of the automute circuit in both hardware and software

modes. On receiving 1024 consecutive zero value audio samples, the analogue stage output mute is

asserted. This may be overdriven from the MUTEB pin to disable the automute function, or output as

a weak (10kohm) output signal.