WM8985
Pre-Production
VOLUME UPDATES
Volume settings will not be applied to the PGAs until a '1' is written to one of the INPPGAVU bits.
This is to allow left and right channels to be updated at the same time, as shown in Figure 13.
Figure 13 Simultaneous Left and Right Volume Updates
If the volume is adjusted while the signal is a non-zero value, an audible click can occur as shown in
Figure 14.
Figure 14 Click Noise During Volume Update
In order to prevent this click noise, a zero cross function is provided. When enabled, this will cause
the PGA volume to update only when a zero crossing occurs, minimising click noise as shown in
Figure 15.
PP, Rev 3.4, October 2006
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
