CS3318 Datasheet, PDF (22/44 Pages) Cirrus Logic – 8-Channel Analog Volume Control

CS3318
5.7 Zero-Crossing Detection
The CS3318 incorporates comprehensive zero-crossing detection features to provide for noise-free level
transitions. Three zero-crossing detection modes and 8 selectable time-out periods are available for en-
hanced flexibility. Zero-crossing detection and time-out is implemented independently for each channel.
5.7.1
Zero-Crossing Modes
The zero-crossing mode for all channels within the CS3318 are configured via the ZCMode[1:0] bits in the
Device Config 2 register. By default, zero-crossing mode 1 is selected. The zero-crossing modes are de-
tailed in Table 2.
Mode
Zero-Crossing Function
0 Volume changes take effect immediately.
1 Volume changes take effect on a signal zero-crossing. If a zero-crossing is not detected before the time-
out period has elapsed, the volume change will be implemented immediately when the time-out period
elapses. If the volume setting is changed again before the original volume change has been imple-
mented, the original change will be discarded, the time-out period will be reset, and the new volume set-
ting will take effect when a zero-crossing is detected or the time-out period elapses.
2 Volume changes take effect on a signal zero-crossing. If a zero-crossing is not detected before the time-
out period has elapsed, the volume change will be implemented immediately when the time-out period
elapses. If the volume setting is changed again before the original volume change has been imple-
mented, the original volume change will be implemented immediately upon reception of the new volume
change command, the time-out period will be reset, and the new volume setting will take effect when a
zero-crossing is detected or the time-out period elapses.
Table 2. Zero-Crossing Modes
Referenced Control
Register Location
ZCMode[1:0] ....................... “Zero-Crossing Mode (Bits 1:0)” on page 35
5.7.2
Zero-Crossing Time-Out
When in zero-crossing mode 1 or 2, the zero-crossing time-out period dictates how long the CS3318 will
wait for a signal zero-crossing before implementing the requested volume change without a zero-cross-
ing, thereby allowing the possibility of audible artifacts. The CS3318 provides 8 selectable time-out peri-
ods ranging from 5 ms to 50 ms; these are shown in Table 3.
Time-Out Setting
0
1
2
3
4
5
6
7
Time-Out Period
5 ms
10 ms
15 ms
18 ms
20 ms
30 ms
40 ms
50 ms
Table 3. Zero-Crossing Time-Out Periods
The zero-crossing time-out period for all channels within the CS3318 is configured via the TimeOut[2:0]
bits in the Device Config 2 register. The time-out period is set to 18 ms (setting 3) by default.
Referenced Control
Register Location
TimeOut[2:0] ....................... “Zero-Crossing Time-Out Period (Bits 4:2)” on page 34
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