WM8990ECS/RV Wolfson Microelectronics, WM8990ECS/RV Datasheet - Page 60

• Manufacturer Part Number: WM8990ECS/RV
• Description: Audio CODECs Stereo CODEC w.Class AB/D speaker driver
• Manufacturer: Wolfson Microelectronics

Specifications of WM8990ECS/RV

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8990
w
DAC INTERFACE VOLUME BOOST
A digital gain function is available at the audio interface to boost the DAC volume when a small
signal is received on DACDAT. This is controlled using register bits DAC_BOOST[1:0]. To prevent
clipping at the DAC input, this function should not be used when the boosted DAC data is expected
to be greater than 0dBFS.
Table 21 DAC Interface Volume Boost
DIGITAL SIDETONE
A digital sidetone is available when ADCs and DACs are operating at the same sample rate. Digital
data from either left or right ADC can be mixed with the audio interface data on the left and right DAC
channels. Sidetone data is taken from the ADC high pass filter output, to reduce low frequency noise
in the sidetone (e.g. wind noise or mechanical vibration).
The digital sidetone will not function when ADCs and DACs are operating at different sample rates.
When using the digital sidetone, it is recommended that the ADCs are enabled before un-muting the
DACs to prevent pop noise. The DAC volumes and sidetone volumes should be set to an appropriate
level to avoid clipping at the DAC input.
The digital sidetone is controlled as shown in Table 22.
Table 22 Digital Sidetone Control
R5 (05h)
R13 (0Dh)
REGISTER
REGISTER
ADDRESS
ADDRESS
11:10
12:9
8:5
3:2
1:0
BIT
BIT
ADCL_DAC_SVOL
[3:0]
ADCR_DAC_SVOL
[3:0]
ADC_TO_DACL
[1:0]
ADC_TO_DACR
[1:0]
DAC_BOOST
[1:0]
LABEL
LABEL
00b
DEFAULT
0000b
0000b
00b
00b
DEFAULT
00 = 0dB
01 = +6dB (Input data must not
exceed -6dBFS)
10 = +12dB (Input data must not
exceed -12dBFS)
11 = +18dB (Input data must not
exceed -18dBFS)
DAC Input Volume Boost
Left Digital Sidetone Volume
(See Table 23 for volume range)
Right Digital Sidetone Volume
(See Table 23 for volume range)
Left DAC Digital Sidetone Source
00 = No sidetone
01 = Left ADC
10 = Right ADC
11 = Reserved
Right DAC Digital Sidetone Source
00 = No sidetone
01 = Left ADC
10 = Right ADC
11 = Reserved
DESCRIPTION
DESCRIPTION
PD, March 2009, Rev 4.0
Production Data
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