Production Data
WM8945
DIGITAL BEEP GENERATOR
The WM8945 provides a digital signal generator which can be used to inject an audio tone (beep) into
the DAC signal path. The output of the beep generator is digitally mixed with the DAC outputs, after
the DAC digital volume.
The beep is enabled using BEEP_ENA. The beep function creates an approximation of a Sine wave.
The audio frequency is set using BEEP_RATE. The beep volume is set using BEEP_GAIN. Note that
the volume of the digital beep generator is not affected by the DAC volume or DAC mute controls.
The DAC_AUTOMUTE bit should not be set when the BEEP generator is used.
The digital beep generator control fields are described in Table 28.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R37 (25h)
BEEP_GAIN [3:0]
0000
Digital Beep Volume Control
0000 = mute
6:3
Beep Control
1
0001 = -83dB
0010 = -77dB
… (6dB steps)
1111 = +1dB
BEEP_RATE [1:0]
BEEP_ENA
01
Beep Waveform Control
00 = Reserved
01 = 1kHz
2:1
10 = 2kHz
11 = 4kHz
0
Digital Beep Enable
0 = Disabled
0
1 = Enabled
Note that the DAC and associated
signal path needs to be enabled
when using the digital beep.
Table 28 Digital Beep Generator
PD, May 2011, Rev 4.1
49
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
