WM8955BL Wolfson Microelectronics, WM8955BL Datasheet - Page 18

• Manufacturer Part Number: WM8955BL
• Description: Stereo DAC
• Manufacturer: Wolfson Microelectronics

w
WM8955BL
TONE CONTROL
The WM8955BL provides separate controls for bass and treble with programmable gains and filter
characteristics. This function operates on digital audio data before it is passed to the audio DACs.
Bass control can take two different forms:
•
•
Treble control applies a user programmable gain, without any adaptive boost function.
Table 4 Tone Control
Note:
All cut-off frequencies change proportionally with the DAC sample rate.
R12 (0Ch)
Bass Control
R13 (0Dh)
Treble Control
REGISTER
ADDRESS
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.
7
6
3:0
6
3:0
BIT
BB
BC
BASS
TC
TRBL
LABEL
0
0
1111 (OFF)
0
1111
(Disabled)
DEFAULT
Bass Mode
0 = Linear bass control
1 = Adaptive bass boost
Bass Filter Characteristic
0 = Low Cutoff (130 Hz at 48kHz sampling)
1 = High Cutoff (200 Hz at 48kHz sampling)
Bass Intensity
Code
0000
0001
0010
…
0111
…
1011-1101
1110
1111
Treble Filter Characteristic
0 = High Cutoff (8kHz at 48kHz sampling)
1 = Low Cutoff (4kHz at 48kHz sampling)
Treble Intensity
0000 or 0001 = +9dB
0010 = +7.5dB
… (1.5dB steps)
1011 to 1110 = -6dB
1111 = Disable
BB=0
+9dB
DESCRIPTION
+9dB
+7.5dB
(1.5dB steps)
0dB
(1.5dB steps)
-6dB
-6dB
PD Rev 4.1 February 2007
Bypass (OFF)
Production Data
BB=1
15 (max)
14
13
…
8
…
4-2
1 (min)
18