AK4683_07 Datasheet, PDF (39/84 Pages) Asahi Kasei Microsystems – Asynchronous Multi-Channel Audio CODEC with DIR/T

[AK4683]
■ Soft mute operation
The ADC and DAC have the soft mute function. The soft mute operation is performed at digital domain. When the
SMAD/SMDA bits go to “1”, the output signal is attenuated by -∞ during ATT_DATA×ATT transition time (Table 37,
Table 38) from the current ATT level. When the SMAD/SMDA bits are returned to “0”, the mute is cancelled and the
output attenuation gradually changes to the ATT level during ATT_DATA×ATT transition time. If the soft mute is
cancelled before attenuating to -∞ after starting the operation, the attenuation is discontinued and returned to ATT level
by the same cycle. The soft mute is effective for changing the signal source without stopping the signal transmission.
SMAD/SMDA bits
ATT Level
(1)
Attenuation
(1)
(3)
-∞
GD
GD
(2)
AOUT
DZF
(for SMDA)
(4)
8192/fs
Notes:
(1) ATT_DATA×ATT transition time (Table 37, Table 38). For example, in Normal Speed Mode, this time is
1061/fs cycles (1792/fs) at ATT_DATA=00H. ATT transition of the soft-mute is from 00H to FFH
(2) The analog output corresponding to the digital input has a group delay, GD.
(3) If the soft mute is cancelled before attenuating to -∞ after starting the operation, the attenuation is discontinued
and returned to ATT level by the same cycle.
(4) When the input data at all the channels of the group are continuously zeros for 8192 cycles, DZF pin of each
channel goes to “H”. DZF pin immediately goes to “L” if the input data of either channel of the group are not
zero after going DZF “H”.
Figure 20. Soft mute and zero detection
MS0427-E-02
- 39 -
2007/04