wm8982gefl-v Wolfson Microelectronics plc, wm8982gefl-v Datasheet - Page 52

• Manufacturer Part Number: wm8982gefl-v
• Description: Mono Codec With Speaker Driver And Video Buffer
• Manufacturer: Wolfson Microelectronics plc

WM8982
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Table 38 Speaker Volume Control
The signal to be output on SPKOUTP/SPKOUTN comes from Output Mixer 1 / Output Mixer 2
circuits and can be any combination of the DAC output, the Bypass path (output of the input boost
stage) and the AUX inputs. The SPKOUTP/SPKOUTN volume is controlled by the SPKOUTPVOL/
SPKOUTNVOL register bits. Note that gains over 0dB may cause clipping if the signal is large. The
SPKOUTPMUTE/ SPKOUTNMUTE register bits cause the speaker outputs to be muted (the output
DC level is driven out). The output pins remain at the same DC level (DCOP), so that no click noise
is produced when muting or un-muting
The speaker output stages also have a selectable gain boost of 1.5x (3.52dB). When this boost is
enabled the output DC level is also level shifted (from AVDD/2 to 1.5xAVDD/2) to prevent the signal
from clipping. A dedicated amplifier BUFDCOP, as shown in Figure 28, is used to perform the DC
level shift operation.
operating mode. It should also be noted that if SPKVDD is not equal to or greater than 1.5xAVDD
this boost mode may result in signals clipping. Table 40 summarises the effect of the SPKRBOOST
control bits.
Note: When boost mode is selected, it is necessary to set LOUT2MUTE (R54[6]) and ROUT2MUTE
(R55[6]) bits for either output to be muted
R54
SPKOUTP
Volume
control
R55
SPKOUTN
Volume
control
REGISTER
ADDRESS
7
6
5:0
8
7
6
5:0
8
BIT
This buffer must be enabled using the BUFDCOPEN register bit for this
SPKOUTPZC
SPKOUTPMUTE
SPKOUTPVOL
SPKVU
SPKOUTNZC
SPKOUTNMUTE
SPKOUTNVOL
SPKVU
LABEL
Not latched
Not latched
DEFAULT
111001
111001
0
0
0
0
1 = Change gain on zero cross only
0 = Change gain immediately
0 = Normal operation
1 = Mute
000000 = -57dB
...
111001 = 0dB
...
111111 = +6dB
SPKOUTP and SPKOUTN volumes
do not update until a 1 is written to
SPKVU (in reg 54 or 55)
Speaker volume zero cross enable:
1 = Change gain on zero cross only
0 = Change gain immediately
Speaker -ve output mute:
0 = Normal operation
1 = Mute
Speaker -ve output volume:
000000 = -57dB
...
111001 = 0dB
...
111111 = +6dB
SPKOUTP and SPKOUTN volumes
do not update until a 1 is written to
SPKVU (in reg 54 or 55)
Speaker volume zero cross enable:
Speaker +ve output mute:
Speaker +ve output volume:
PP, Rev 3.2, September 2008
DESCRIPTION
Pre-Production
52