WM8753L
Advanced Information
REGISTER
ADDRESS
BIT
LABEL
LDVU
DEFAULT
DESCRIPTION
R8 (08h)
8
0
Left DAC Volume Update
Left Channel
Digital Volume
0 = Store LDACVOL in intermediate
latch (no gain change)
1 = Update left and right channel
gains (left
= LDACVOL, right =
intermediate latch)
7:0
LDACVOL
[7:0]
11111111
( 0dB )
Left DAC Digital Volume Control
0000 0000 = Digital Mute
0000 0001 = -127dB
0000 0010 = -126.5dB
... 0.5dB steps up to
1111 1111 = 0dB
R9 (09h)
8
RDVU
0
Left DAC Volume Update
Right Channel
Digital Volume
0 = Store RDACVOL in intermediate
latch (no gain change)
1 = Update left and right channel
gains (left = intermediate latch, right
= RDACVOL)
7:0
RDACVOL
[7:0]
11111111
( 0dB )
Right DAC Digital Volume Control
similar to LDACVOL
Table 25 Digital Volume Control
GRAPHIC EQUALISER
The WM8753L has a digital graphic equaliser and adaptive bass boost function. This function
operates on digital audio data before it is passed to the audio DACs. Bass enhancement can take two
different forms:
•
Linear bass control: bass signals are amplified or attenuated by a user
programmable gain. This is independent of signal volume, and very high bass gains
on loud signals may lead to signal clipping.
•
Adaptive bass boost: The bass volume is amplified by a variable gain. When the
bass volume is low, it is boosted more than when the bass volume is high. This
method is recommended because it prevents clipping, and usually sounds more
pleasant to the human ear.
Treble control applies a user programmable gain, without any adaptive boost function. Bass and
treble control are completely independent with separately programmable gains and filter
characteristics.
The selectable cut-offs scale with sample frequency to give the following cut-off frequencies at
different sample rates
BC[2:0]
CUT-OFF AT FS=8KHZ
CUT-OFF AT
FS=16KHZ
CUT-OFF AT
FS=48KHZ
000
001
010
011
100
101
22Hz
33.3Hz
50Hz
44Hz
66.7Hz
100Hz
133.3Hz
200Hz
400Hz
130Hz
200Hz
300Hz
400Hz
600Hz
1200Hz
66.7Hz
100Hz
200Hz
Table 26 Bass Filter Cut-off Frequencies for Different Frequencies
AI Rev 3.1 June 2004
37
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
