TLV320AIC3254 Datasheet, PDF (66/168 Pages) Texas Instruments – Ultra Low Power Stereo Audio Codec With Embedded miniDSP

TLV320AIC3254
Ultra Low Power Stereo Audio Codec With Embedded miniDSP
SLAS549A – SEPTEMBER 2008 – REVISED OCTOBER 2008
www.ti.com
5.12.3 User Programmable Filters
Depending on the selected processing block, different types and orders of digital filtering are available. Up
to 6 biquad sections are available for specific processing blocks.
The coefficients of the available filters are arranged as sequentially-indexed coefficients in two banks. If
adaptive filtering is chosen, the coefficient banks can be switched on-the-fly. For more details on adaptive
filtering please see Section 5.15.3.
The coefficients of these filters are each 24-bits wide, in two's-complement and occupy 3 consecutive 8-bit
registers in the register space. For default values please see Section 6.6.
5.12.3.1 1st-Order IIR Section
The IIR is of first-order and its transfer function is given by
Figure 5-29.
H(z)
=
N₀
2 ²³
+ N₁z ^-1
- D₁z ^-1
(5-8)
The frequency response for the 1^st order IIR Section with default coefficients is flat
Filter
1^st Order IIR
Table 5-14. DAC IIR Filter Coefficients
Filter Coefficient
N0
N1
D1
ADC Coefficient Left Channel ADC Coefficient Right
Channel
C65 (Pg 46, Reg 28,29,30)
C68 (Pg 46, Reg 40,41,42)
C66 (Pg 46. Reg 32,33,34)
C69 (Pg 46, Reg 44,45,46)
C67 (Pg 46, Reg 36,37,38)
V70 (Pg 46, Reg 48,49,50)
5.12.3.2 Biquad Section
The transfer function of each of the Biquad Filters is given by
H(z)
=
N₀
2²³
+ 2 * N₁z ^-1 + N₂z ^-2
- 2 * D₁z ^-1 - D₂z ^-2
(5-9)
Filter
BIQUAD A
BIQUAD B
BIQUAD C
BIQUAD D
Coefficient
N0
N1
N2
D1
D2
N0
N1
N2
D1
D2
N0
N1
N2
D1
D2
N0
Table 5-15. DAC Biquad Filter Coefficients
Left DAC Channel
C1 (Pg 44, Reg 12,13,14)
C2 (Pg 44, Reg 16,17,18)
C3 (Pg 44, Reg 20,21,22)
C4 (Pg 44, Reg 24,25,26)
C5 (Pg 44, Reg 28,29,30)
C6 (Pg 44, Reg 32,33,34)
C7 (Pg 44, Reg 36,37,38)
C8 (Pg 44, Reg 40,41,42)
C9 (Pg 44, Reg 44,45,46)
C10 (Pg 44, Reg 48,49,50)
C11 (Pg 44, Reg 52,53,54)
C12 (Pg 44, Reg 56,57,58)
C13 (Pg 44, Reg 60,61,62)
C14 (Pg 44, Reg 64,65,66)
C15 (Pg 44, Reg 68,69,70)
C16 (Pg 44, Reg 72,73,74)
Right DAC Channel
C33 (Pg 45, Reg 20,21,22)
C34 (Pg 45, Reg 24,25,26)
C35 (Pg 45, Reg 28,29,30)
C36 (Pg 45, Reg 32,33,34)
C37 (Pg 45, Reg 36,37,38)
C38 (Pg 45, Reg 40,41,42)
C39 (Pg 45, Reg 44,45,46)
C40 (Pg 45, Reg 48,49,50)
C41 (Pg 45, Reg 52,53,54)
C42 (Pg 45, Reg 56,57,58)
C43 (Pg 45, Reg 60,61,62)
C44 (Pg 45, Reg 64,65,66)
C45 (Pg 45, Reg 68,69,70)
C46 (Pg 45, Reg 72,73,74)
C47 (Pg 45, Reg 76,77,78)
C48 (Pg 45, Reg 80,81,82)
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Application Information
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