Cirrus Logic CS43L21 - Manual (Page 25)

DS723F1 25
CS43L21
4.3.2 Volume Controls
Two digital volume control functions offer independent control of the SDIN signal path into the mixer as
well as a combined control of the mixed signals. The volume controls are programmable to ramp in incre-
ments of 0.125 dB at a rate controlled by the soft ramp/zero cross settings.
The signal paths may also be muted via mute control bits. When enabled, each bit attenuates the signal
to its maximum value. When the mute bit is disabled, the signal returns to the attenuation level set in the
respective volume control register. The attenuation is ramped up and down at the rate specified by the
DAC_SZC[1:0] bits.
4.3.3 Mono Channel Mixer
A channel mixer may be used to create a mix of the left and right channels for the SDIN data. This mix
allows the user to produce a MONO signal from a stereo source. The mixer may also be used to imple-
ment a left/right channel swap.
4.3.4 Beep Generator
The Beep Generator generates audio frequencies across approximately two octave major scales. It offers
three modes of operation: Continuous, multiple and single (one-shot) beeps. Sixteen on and eight off
times are available.
Note: The Beep is generated before the limiter and may affect desired limiting performance. If the limiter
function is used, it may be required to set the Beep volume sufficiently below the threshold to prevent the
peak detect from triggering. Since the master volume control, AOUTx_VOL[7:0], will affect the Beep vol-
ume, DAC volume may alternatively be controlled using the PCMMIXx_VOL[6:0] bits.
Software
Controls:
“PCMX Mixer Volume Control: PCMA (Address 10h) & PCMB (Address 11h)” on page 45“AOUTx
Volume Control: AOUTA (Address 16h) & AOUTB (Address 17h)” on page 49“DAC Output Control
(Address 08h)” on page 42
Software
Controls:
“PCM Channel Mixer (Address 18h)” on page 50 .
Software
Controls: “Beep Frequency & Timing Configuration (Address 12h)” on page 46 , “Beep Off Time & Volume
(Address 13h)” on page 46 , “Beep Configuration & Tone Configuration (Address 14h)” on page 48
Gain
dB
-10dB
0dB
Frequency
T2 = 15 µs
T1=50 µs
F1 F2
3.183 kHz 10.61 kHz
Figure 9. De-Emphasis Curve