IS31AP2121
Integrated Silicon Solution, Inc. – www.issi.com
26
Rev. C, 10/20/2015
Table 9 04h~06h Channel 1~3 Volume Registers
Bit
D7:D0
Name CxV
Default 0001
0100
CxV
Channel x Volume
0000 0000
+12.0dB
0000 0001
+11.5dB
…
0001 0100
+2dB
…
1110 0110
-103.0dB
1110 0111
-
∞
Others
-
∞
Table 10 07h/08h Bass/Treble Tone Registers
Bit
D7:D5
D6:D0
Name -
BTC/TTC
Default xxx
10000
Last two sets of EQ can be programmed as
bass/treble tone boost and cut. When, 0Ah Register,
D6, BTE is set to high, the EQ-7 and EQ-8 will
perform as bass and treble respectively. The -3dB
corner frequency of bass is 360Hz, and treble is
7kHz. The gain range for both filters is +12db ~ -
12dB with 1dB per step.
BTC/TTC
Bass/Treble
Gain
Setting
00000
+12dB
…
00100
+12dB
00101
+11dB
…
10000
0dB
10001
-1dB
…
111xx
-12dB
Table 11 09h Bass Management Crossover
Frequency Register
Bit
D7:D4
D3:D0
Name -
XO
Default xxxx
0010
The IS31AP2121 provides bass management
crossover frequency selection. A 1
st
order high-pass
filter (Channel 1 and 2) and a 2
nd
order low-pass
filter (Channel 3) at selected frequency are
performed.
XO
Bass Management Crossover Frequency
0000 80Hz
0001 100Hz
0010 120Hz
0011 140Hz
0100 160Hz
0101 180Hz
0110 200Hz
0111 300Hz
1000 400Hz
1001 500Hz
1010 600Hz
1011 700Hz
1100 800Hz
1101 900Hz
1110 1000Hz
1111 Reserved
Table 12 0Ah State Control 4 Register
Bit
D7
D6
D5
D4
Name SRBP BTE TBDRCE
NGE
Default
1 0 0 1
Bit
D3
D2
D1
D0
Name EQL PSL DSPB HPB
Default
0 0 0 0
The IS31AP2121 provides several DSP setting as
following.
SRBP
Surround Bypass
0 Surround
enable
1 Surround
bypass
BTE
Bass/Treble Selection Bypass
0 Bass/treble
disable
1 Bass/treble
enable
TBDRCE
Two Band DRC Enable
0
Two band DRC disable
1
Two band DRC enable
NGE
Noise Gate Enable
0
Noise gate disable
1
Noise gate enable
EQL
EQ
Link
0
Each channel uses individual EQ
1
Channel-2 uses channel-1 EQ
PSL
Post-Scale
Link
0
Each channel uses individual post-scale
1
Use channel-1 post-scale