TC9444F Datasheet, PDF (15/28 Pages) Toshiba Semiconductor – Single-Chip karaoke IC II

TC9444F
3.13
ATTA Command
Command to set the digital attenuator level by adding two-byte data.
When the lower 14 bits of the data are set to 2000H, the attenuator level is 0dB.
The upper two bits are the attenuator time constant selection bits. These bits select the soft mute
time constants.
When switching using the MUTE or KEYCON command, the value set by ATTA is also valid for the
automatic mute function.
Table 3.11 ATTA Command
CH
CL
D1
D0
B
0
DSA2 DSA1 ALA13 ALA12 ALA11 ALA10 ALA09 ALA08 ALA07
~
ALA00
Note 8: At a reset, the initial values are DSA = 0H (23 ms) and ALA [13:00] = 2000H (0dB).
The following formula determines the data ALA [13:00] depending on the level (LEVEL [dB]) to be
set.
ALA [13:00] = 2000H*10^ (LEVEL/20).
Table 3.12 Attenuator Setting Level
ALA [13:00]
3FFFH
……
3000H
……
2000H
1FFFH
1FFEH
……
16A7H
……
1000H
……
0002H
0001H
0000H
Output Level
+6.020dB
……
+3.523dB
……
-0.000dB
-0.001dB
-0.002dB
……
-3.000dB
……
-6.021dB
……
-72.247dB
-78.268dB
-Â¥dB
Table 3.13 Attenuator Time Constants
DSA2
L
L
H
H
DSA1
L
H
L
H
fs = 32 kHz
32 ms
128 ms
256 ms
512 ms
Time Constant
fs = 44.1 kHz
23 ms
92 ms
186 ms
372 ms
fs = 48 kHz
21 ms
86 ms
171 ms
341 ms
Time required for change from 0dB to -Â¥dB.
15
2002-01-11