English
Language : 

BU9414FV Datasheet, PDF (44/61 Pages) Rohm – 32bit Audio DSP
◁
BU9414FV
Technical Note
4-27. Direct setting five coefficient of b0, b1, b2, a1 and a2 of Bi-quad Filter
7 bands Parametric Equalizer of main output and of 3 bands Parametric Equalizer of sub output have used the secondary
IIR type digital filter (Bi-quad Filter).
It is possible to set five coefficient 24 bit of b0, b1, b2, a1 and a2 of Bi-quad Filter (-4～+4) directly from an external.
When this function is used, it can do the filter type and frequency setting, Q value (quality factor) setting and gain setting
other than Peaking, Low-Shelf and High-Shelf unrestrictedly.
(Note) five coefficient have the necessity to make below the ±4, there is no read-out function of setting value and an
automatic renewal function of coefficient RAM.
Register for the coefficient transfer of 24bit
Before transferring into coefficient RAM in a lumping, the data is housed in the register for coefficient transfer from the
micro-computer.
Default = 00h
Select Address
Operating explanation
&h8D [ 7:0]
bit[23:16] which transfers 24 bit coefficient
&h8E [ 7:0]
bit[15:8] which transfers 24 bit coefficient
&h8F [ 7:0]
bit[7:0] which transfers 24 bit coefficient
It starts to transmit the coefficient of 24bit into coefficient RAM
Default = 0
Select Address
&h8C [ 7 ]
Value
0
1
Operating explanation
Coefficient transmission stop
Coefficient transmission start
Coefficient number appointment of coefficient RAM
Default = 00h
Select Address
Operating explanation
&h8C [ 6:0]
Coefficient number appointment of coefficient RAM
Appointment of coefficient number other than 14H↔45H is prohibition
Main output　7Band Parametric EQ
Coefficient
number ：
1b04H. + +
Coefficient
number ：
b109H. + +
Coefficient
number ：
1b0EH. + +
Coefficient
number ：
23H.
b0
+
+
Coefficient
number ：
28H.
b0
+
+
Coefficient
number ：
2DH.
b0
+
+
Coefficient
number ：
32H.
b0
+
+
Z-1
15H.
+ b1
Z-1
17H
+ a1
Z-1
1AH.
b1
+
Z-1
1CH
+ a1
Z-1
1FH.
b1
+
Z-1
21H
+ a1
Z-1
24H.
b1
+
Z-1 Z-1
26H
+ a1
29H.
b1
+
Z-1
2BH
+ a1
Z-1
2EH.
b1
+
Z-1 Z-1
30H
+ a1
33H.
b1
+
Z-1
35H
+ a1
Z-1
Z-1
16H.
18H
b2
a2
BAND1 (Main)
Z-1
Z-1
1BH.
b2
1DH
a2
BAND2 (Main)
Z-1
Z-1
20H.
b2
22H
a2
BAND3 (Main)
Z-1
Z-1
25H.
27H
b2
a2
BAND4 (Main)
Z-1
Z-1
2AH.
2CH
b2
a2
BAND5 (Main)
Z-1
2FH.
Z-1
31H
b2
a2
BAND6 (Main)
Z-1
Z-1
34H.
36H
b2
a2
BAND7 (Main)
Sub output　3Band Parametric EQ
Coefficient
number ：
Coefficient
number ：
37H.
b0
+
+
3CH.
b0
+
+
Coefficient
number ：
4b01H. + +
Z-1
38H.
b1
+
Z-1 Z-1
3AH
3DH.
+ a1
+ b1
Z-1 Z-1
3FH
+ a1
42H.
b1
+
Z-1
44H
+ a1
Z-1
39H.
Z-1
3BH
b2
a2
BAND1 (Sub)
Z-1
3EH.
Z-1
40H
b2
a2
BAND2 (Sub)
Z-1
43H.
Z-1
45H
b2
a2
BAND3 (Sub)
www.rohm.com
© 2012 ROHM Co., Ltd. All rights reserved.
44/57
2012.03 - Rev.A
 ▷