WM8777
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TONE CONTROL GAIN
The amplitude of the tone response is controlled by writing gain values to the appropriate gain
registers. The front left and right channels share gain registers, whilst the centre channel may be
controlled independently. Table 3 shows how the attenuation levels for the tone control blocks are
selected from the 4-bit code words.
The tone control attenuation registers share the zero-cross detect circuit used by the analogue
volume control. Thus the ZCEN enable bit for a particular channel can be used to determine whether
or not the treble/bass attenuation registers for that channel are updated only on a zero-cross
condition.
CUT/BOOST
CODE[3:0]
ATTENUATION LEVEL
0000
+1dB
0001
+2dB
BOOST
.
.
.
.
1001
0000
0001
.
+10dB
-1dB
-2dB
.
CUT
.
.
1001
-10dB
Table 3 Tone Control Attenuation Levels
PP Rev 1.94 November 2004
16
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
