CS4525 datasheet(30/91 Pages) CIRRUS

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DS726A1

CS4525

6.1.4.2

Digital Signal Processing High-Pass Filter

The CS4525 includes a high-pass filter at the beginning of the digital signal processing chain to remove

any DC content from the input signal prior to the remaining internal digital signal processing blocks. The

high-pass filter operates by continuously subtracting a measure of the DC offset from the input signal and

may be used regardless of the input data source.

The digital signal processing high-pass filter can be disabled by clearing the EnDigHPF bit.

6.1.4.3

Channel Mixer

The CS4525 implements independent channel mixers to provide for both mono mixes and channel swaps

for the left and right channels. The channel mixers are controlled by the LChMix[1:0] and RChMix[1:0] bits

in the Mixer Config register.

To allow stereo headphone operation when a mono mix is configured, when the HP_DETECT/MUTE pin

is configured for headphone detection (the HP/Mute bit is set), the operation of the left channel mixer is

affected by the active state of the headphone detection input signal. In this configuration, when the left

channel mixer is configured for a mono mix (LChMix[1:0] = 01 or 10) and the headphone detection input

signal becomes active, the left channel mixer will be automatically reconfigured to output the left channel,

thereby disabling the mono mix. When the headphone detection input signal becomes inactive, the mixer

will be automatically reconfigured to operate as dictated by the LChMix[1:0] bits.

It should be noted that the right channel mixer output is unaffected by the headphone detection input sig-

nal and will always operate as dictated by the RChMix[1:0] bits.

Referenced Control

EnDigHPF ........................... “Digital Signal Processing High-Pass Filter (EnDigHPF)” on page 71

Referenced Control

LChMix[1:0[ ......................... “Left Channel Mixer (LChMix[1:0])” on page 71

RChMix[1:0] ........................ “Right Channel Mixer (RChMix[1:0])” on page 70

HP/Mute .............................. “HP_Detect/Mute Pin Mode (HP/Mute)” on page 65

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