Cirrus Logic CS3318 - Manual (Page 22)

22 DS693F1
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 .
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 .
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.
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
Time-Out Setting Time-Out Period
0 5 ms
1 10 ms
2 15 ms
3 18 ms
4 20 ms
5 30 ms
6 40 ms
7 50 ms
Table 3. Zero-Crossing Time-Out Periods
Referenced Control Register Location
TimeOut[2:0] ....................... “Zero-Crossing Time-Out Period (Bits 4:2)” on page 34