WM9711 datasheet(18/66 Pages) WOLFSON

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WM9711L

Production Data

PD Rev 4.1 April 2004

AUDIO ADC

The WM9711L has a stereo sigma-delta ADC to digitise audio signals. The ADC achieves high

quality audio recording at low power consumption. The ADC sample rate can be controlled by writing

to a control register (see “Variable Rate Audio”). It is independent of the DAC sample rate.

To save power, the left and right ADCs can be separately switched off using the PD11 and PD12

bits, whereas PR0 disables both ADCs (see “Power Management” section). If only one ADC is

running, the same ADC data appears on both the left and right AC-Link slots.

HIGH PASS FILTER

The WM9711L audio ADC incorporates a digital high-pass filter that eliminates any DC bias from the

ADC output data. The filter is enabled by default. For DC measurements, it can be disabled by

writing a ‘1’ to the HPF bit (register 5Ch, bit 3).

ADC SLOT MAPPING

By default, the output of the left audio ADC appears on slot 3 of the SDATAIN signal (pin 8), and the

right ADC data appears on slot 4. However, the ADC output data can also be sent to other slots, by

setting the ASS (ADC slot select) control bits as shown below.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

HPF

High-pass filter disable

0: Filter enabled (for audio)

1: Filter disabled (for DC measurements)

5Ch

Additional

Function

Control

1:0

ASS

ADC to slot mapping

00: Left = Slot 3, Right = Slot 4 (default)

01: Left = Slot 7, Right = Slot 8

10: Left = Slot 6, Right = Slot 9

11: Left = Slot 10, Right = Slot 11

Table 6 ADC Slot Mapping

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