wm8742 Wolfson Microelectronics plc, wm8742 Datasheet - Page 40

• Manufacturer Part Number: wm8742
• Description: 24-bit 192khz Dac With Advanced Digital Filtering
• Manufacturer: Wolfson Microelectronics plc

WM8742
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OVERSAMPLING RATE CONTROL
The user has control of the oversampling ratio of the WM8742, and can set to the device to operate in
low, medium or high rate modes. For optimum operation of the digital filtering and other processing
on the WM8742 in PCM hardware mode, the user must ensure the correct value of OSR is set at all
times. Table 47 shows the correct settings:
Table 47 OSR/DSDR Hardware Control Pin Function
MUTE PIN
A soft mute can be applied to the WM8742 in the digital domain in all PCM. A logic low on the
MUTEB pin will cause the attenuation to ramp to infinite attenuation at a rate of 1022x(4/fs). Setting
MUTEB high will return the signal gain to its previous value.
characteristic.
In DSD Direct mode the MUTEB pin controls the analogue mute in the DAC. This analogue mute is a
‘hard’ mute and is applied and released as soon as the MUTEB pin is toggled.
Table 48 MUTEB Hardware Control Pin Function
Figure 26 Hardware Control Mode Soft Mute Characteristic
0
PIN
PIN
22
25
0.02
OSR/DSDR
MUTEB/
SDOUT
NAME
NAME
0.04
Oversampling Rate Selection
0 = Low rate (32/44.1/48kHz)
Z = Medium rate (88.2/96kHz)
1 = High rate (176.4/192kHz)
Mute control
0 = Mute on (no output)
1 = Mute off (normal operation
0.06
DESCRIPTION
DESCRIPTION
Time (s)
0.08
0.1
Figure 26 shows the soft mute
0.12
PD, Rev 4.2,August 2009
0.14
Production Data
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