ISD91200 Series Technical Reference Manual
Release Date: Sep 16, 2019
- 443 -
Revision 2.4
Configuring Coefficient
1. BIQ function work on 6 stages, set BIQ_CTL.STAGE=0, BIQ function will call 30 coefficients
from 0x0 ~0x074
2. BIQ function work on 5 stages, set BIQ_CTL.STAGE=1, BIQ function will call 25 coefficients
from 0x00 ~0x060
3. If High pass filter is on (BIQ_CTL.HPFON=1), BIQ function automatically set 6 stages, one for
HPF. BIQ function will call 30 coefficients.
4. BIQ function work on one stage, set first stage coefficient and bypass other stages set b0 =
0x1000, b1 =0,b2=0,a1 =0,a2=0.
5. BIQ function work on two stages, set first and second stages coefficient and bypass other
stages set b0 = 0x1000, b1 =0,b2=0,a1 =0,a2=0.
6. BIQ function work on three stages, set first, second and third stages coefficient and bypass other
stages set b0 = 0x1000, b1 =0,b2=0,a1 =0,a2=0
7. BIQ function work on four stages, set first, second, third and fourth stages coefficient and bypass
other stages set b0 = 0x1000, b1 =0,b2=0,a1 =0,a2=0
7.7.2
Register Map
7.7.2.1
BIQ filter coefficients registers
Register
Offset
R/W
Description
Reset Value
BIQ Base Address:
BIQ_BA = 0x400B_0000
BIQ_COEFF0
0x00
R/W
Coefficient b0 In H(z) Transfer Function
(3.16 format) - 1
st
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF1
0x004
R/W
Coefficient b1 In H(z) Transfer Function
(3.16 format) - 1
st
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF2
0x008
R/W
Coefficient b2 In H(z) Transfer Function
(3.16 format) - 1
st
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF3
0x00c
R/W
Coefficient a1 In H(z) Transfer Function
(3.16 format) - 1
st
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF4
0x010
R/W
Coefficient a2 In H(z) Transfer Function
(3.16 format) - 1
st
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF5
0x14
R/W
Coefficient b0 In H(z) Transfer Function
(3.16 format) - 2
nd
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF6
0x018
R/W
Coefficient b1 In H(z) Transfer Function
(3.16 format) - 2
nd
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF7
0x01c
R/W
Coefficient b2 In H(z) Transfer Function
(3.16 format) - 2
nd
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF8
0x020
R/W
Coefficient a1 In H(z) Transfer Function
(3.16 format) - 2
nd
stage BIQ Coefficients
0x0000_0000
BIQ_COEFF9
0x024
R/W
Coefficient a2 In H(z) Transfer Function
(3.16 format) - 2
nd
stage BIQ Coefficients
0x0000_0000