CS4525 datasheet(36/91 Pages) CIRRUS

36 / 91 page

DS726A1

CS4525

6.1.4.9

Volume and Muting Control

The CS4525’s volume control architecture provides the ability to control the level of each output channel

on both an individual and master basis.

Individual control allows the volume and mute state of a single channel to be changed independently from

the other channels within the device. The CS4525 provides 3 individual volume and muting controls, each

permanently assigned to one channel within the device.

Each channel has a corresponding Ch X Vol register used to gain or attenuate the channel from +24 dB

to -103 dB in 0.5 dB steps. Each output can be independently muted via the MuteChX bits in the Mute

Control register.

Master control allows the volume of all channels to be changed simultaneously by offsetting each chan-

nel’s individual volume setting by +24 dB to -103 dB in 0.5 dB steps. Master volume control is accom-

plished via the Master Vol register.

The PWM outputs can be configured to output silence as a modulated signal or an exact 50% duty cycle

signal during a mute condition. This selection is achieved via the Mute50/50 bit in the Volume Cfg register.

The AutoMute bit in the same register dictates whether the device will automatically mute after the recep-

tion of 8192 consecutive samples of static 0 or -1. When the AutoMute function is enabled, a single sam-

ple of non-static data will cause the automatic mute to be released.

The CS4525 implements soft-ramp and zero-crossing detection capabilities to provide noise-free level

transitions. When the zero-crossing function is enabled, all volume and muting changes are made on an

output signal zero-crossing. The zero-crossing detection function is implemented independently for each

channel. When the soft-ramp function is enabled, the volume is ramped from its initial to its final level at

a rate of ½ dB every 4 samples for 32, 44.1, and 48 kHz sample rates, and ½ dB every 8 samples for a

96 kHz sampling rate.

All volume and muting changes are implemented as dictated by the soft-ramp and zero-cross settings

configured by the SZCMode[1:0] bits in the Volume Cfg register.

Referenced Control

Ch X Vol .............................. “Channel 1, 2, & 3 Volume Control (Address 58h, 59h, & 5Ah)” on page 78

Master Vol ........................... “Master Volume Control (Address 57h)” on page 77

Mute50/50 ........................... “Enable 50% Duty Cycle for Mute Condition (Mute50/50)” on page 75

AutoMute............................. “Auto-Mute (AutoMute)” on page 75

SZCMode ............................ “Soft Ramp and Zero Cross Control (SZCMode[1:0])” on page 75

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