Pre-Production
WM8940
REGISTER
ADDRESS
BIT
LABEL
SPKZC
DEFAULT
DESCRIPTION
R54
7
6
0
Speaker Volume control zero cross
enable:
Speaker
volume control
1 = Change gain on zero cross only
0 = Change gain immediately
Speaker output mute enable
0=Speaker output enabled
1=Speaker output muted (VMIDOP)
Speaker Volume Adjust
111111 = +6dB
SPKMUTE
1
5:0
SPKVOL
[5:0]
111001
(0dB)
111110 = +5dB
… (1.0 dB steps)
111001=0dB
…
000000=-57dB
Table 35 SPKOUT Volume Control
ZERO CROSS TIMEOUT
A zero-cross timeout function is also provided so that if zero cross is enabled on the input or output
PGAs the gain will automatically update after a timeout period if a zero cross has not occurred. This
is enabled by setting SLOWCLKEN. The timeout period is either 31Hz or 47Hz.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R7
0
SLOWCLKEN
0
Slow clock enable. Used for both the jack
insert detect de-bounce circuit and the
zero cross timeout.
Additional
control
0 = slow clock disabled
1 = slow clock enabled
Table 36 Timeout Clock Enable Control
MONO MIXER AND OUTPUT
The MONOOUT pin can drive a 16Ω or 32Ω headphone or a line output or be used as a DC
reference for a headphone output (see Headphone Output section). It can be selected to drive out
any combination of DAC, Bypass (output of input BOOST stage) and AUX. This output is enabled
by setting bit MONOEN.
Pre-Production, Rev 3.0, February 2007
45
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