Cirrus Logic CS4271 - Manual (Page 41)

CS4271
DS592F1 41
itored and implemented for each channel. See Table 14 on page 41.
Soft Ramp and Zero Cross Enable
Soft Ramp and Zero Cross Enable dictate that signal level changes, either by attenuation changes or
muting, will occur in 1/8 dB steps and be implemented on a signal zero crossing. The 1/8 dB level
change will occur after a time-out period between 512 and 1024 sample periods (10.7 ms to 21.3 ms
at 48 kHz sample rate) if the signal does not encounter a zero crossing. The zero cross function is
independently monitored and implemented for each channel. See Table 14 on page 41.
8.3.3 ATAPI Channel Mixing and Muting (Bits 3:0)
Function:
The CS4271 implements the channel mixing functions of the ATAPI CD-ROM specification. See
Table 15 on page 42
Table 14. Soft Cross or Zero Cross Mode Selection
Soft ZeroCross Mode
0 0 Changes to affect immediately
0 1 Zero Cross enabled
1 0 Soft Ramp enabled (default)
1 1 Soft Ramp and Zero Cross enabled
Σ
A Channel
Volume
Control
Left Channel
Audio Data
Right Channel
Audio Data
B Channel
Volume
Control
AoutA
AoutB
Figure 20. ATAPI Block Diagram