WM8945 datasheet(28/169 Pages) WOLFSON

28 / 169 page

WM8945

Production Data

PD, May 2011, Rev 4.1

The digital microphone interface control fields are described in Table 6.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R2 (02h)

Power

Management 1

DMIC_ENA

Enables Digital Microphone mode

0 = Audio DSP input is from ADC

1 = Audio DSP input is from digital

microphone interface

When DMIC_ENA = 0, the Digital

microphone clock (DMICCLK) is

held low.

Table 6 Digital Microphone Interface Control

ANALOGUE-TO-DIGITAL CONVERTER (ADC)

The WM8945 uses a 24-bit sigma-delta ADC. The use of multi-bit feedback and high oversampling

rates reduces the effects of jitter and high frequency noise. The ADC full-scale input level is

proportional to LDOVOUT. See “Electrical Characteristics” section for further details. Any input signal

greater than full scale may overload the ADC and cause distortion.

The ADCs and associated digital record filters are enabled by the ADCL_ENA register bit.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R2 (02h)

Power

Management

ADCL_ENA

Left ADC Enable

0 = Disabled

1 = Enabled

ADCL_ENA must be set to 1 when

processing left channel data from

the ADC or Digital Microphone.

Table 7 ADC Enable Control

ADC VOLUME CONTROL

The output of the ADC can be digitally amplified or attenuated over a range from -71.625dB to

+23.625dB in 0.375dB steps. The volume of each channel is controlled using ADCL_VOL. The ADC

Volume is part of the ADC Digital Filters block. The gain for a given eight-bit code X is given by:

0.375

 (X-192) dB for 1  X  255;

MUTE for X = 0

The ADC_VU bit controls the loading of digital volume control data. The ADCL_VOL control data is

only loaded into the respective control register when ADC_VU = 1.

The output of the ADC can be digitally muted using the ADCL_MUTE or ADC_MUTEALL bits.

WM8945 数据表(PDF) 28 Page - Wolfson Microelectronics plc

WM8945 数据表(HTML) 28 Page - Wolfson Microelectronics plc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载