28

DS566F1

CS4351

6.5.1

Digital Volume Control (VOL7:0) Bits 7-0

Default = 00h (0 dB)

Function:

The Digital Volume Control registers allow independent control of the signal levels in 1/2 dB increments

from 0 to -127.5 dB. Volume settings are decoded as shown in Table 9. The volume changes are imple-

mented as dictated by the Soft and Zero Cross bits in the Power and Muting Control register.

The actual attenuation is determined by taking the decimal value of the volume register and multiplying

by 6.02/12.

6.6

Ramp and Filter Control - Register 07h

6.6.1

Soft Ramp and Zero Cross Control (SZC1:0) Bits 7-6

Default = 10

Function:

Immediate Change

When Immediate Change is selected all level changes will take effect immediately in one step.

Zero Cross

Zero Cross Enable dictates that signal level changes, either by attenuation changes or muting, will occur

on a signal zero crossing to minimize audible artifacts. The requested level change will occur after a time-

out period between 512 and 1024 sample periods (10.7 ms to 21.3 ms at 48 kHz sample rate) if the signal

does not encounter a zero crossing. The zero cross function is independently monitored and implemented

for each channel.

Soft Ramp PCM

Soft Ramp allows level changes, both muting and attenuation, to be implemented by incrementally ramp-

ing, in 1/8 dB steps, from the current level to the new level at a rate of 1 dB per 8 left/right clock periods.

Binary Code

Decimal Value

Volume Setting

00000000

0

0 dB

00000001

1

-0.5 dB

00000110

6

-3.0 dB

11111111

255

-127.5 dB

Table 9. Example Digital Volume Settings

76

543

21

0

SZC1

SZC0

RMP_UP

RMP_DN

Reserved

FILT_SEL

Reserved

Reserved

10

110

00

1

SZC1 SZC0

Description

0

0

Immediate Change

01

Zero Cross

10

Soft Ramp

1

1

Soft Ramp on Zero Crossings