
M
n
n 0
H(z)
FIR z
M
24 for PRB _ R6, PRB _ R18
M
19 for PRB _ R12
-
=
www.ti.com
SLAS644B – JULY 2009 – REVISED OCTOBER 2009
(3)
The coefficients of the FIR filters are 16-bit 2s-complement format (2 bytes each) and correspond to the
ADC coefficient space as listed in
Table 5-19. Note that the default (reset) coefficients are not vaild for the
FIR filter. When the FIR filter is used, all applicable coefficients must be reprogrammed by the user. To
reprogram the FIR filter coefficients as an all-pass filter, write value 0x00 to page 4 / registers 24, 25, 34,
35, 44, 45, 54, and 55.
Table 5-19. ADC FIR Filter Coefficients
Filter Coefficient
FIlter Coefficient RAM Location
Default (Reset) Values – Not Valid for the FIR Filter – Must Be
Reprogrammed by User
FIR0
Page 4 / register 14 and page 4 / register 15
0x7FFF (decimal 1.0 – LSB value)
FIR1
Page 4 / register 16 and page 4 / register 17
0x0000
FIR2
Page 4 / register 18 and page 4 / register 19
0x0000
FIR3
Page 4 / register 20 and page 4 / register 21
0x0000
FIR4
Page 4 / register 22 and page 4 / register 23
0x0000
FIR5
Page 4 / register 24 and page 4 / register 25
0x7FFF (decimal 1.0 – LSB value)
FIR6
Page 4 / register 26 and page 4 / register 27
0x0000
FIR7
Page 4 / register 28 and page 4 / register 29
0x0000
FIR8
Page 4 / register 30 and page 4 / register 31
0x0000
FIR9
Page 4 / register 32 and page 4 / register 33
0x0000
FIR10
Page 4 / register 34 and page 4 / register 35
0x7FFF (decimal 1.0 – LSB value)
FIR11
Page 4 / register 36 and page 4 / register 37
0x0000
FIR12
Page 4 / register 38 and page 4 / register 39
0x0000
FIR13
Page 4 / register 40 and page 4 / register 41
0x0000
FIR14
Page 4 / register 42 and page 4 / register 43
0x0000
FIR15
Page 4 / register 44 and page 4 / register 45
0x7FFF (decimal 1.0 – LSB value)
FIR16
Page 4 / register 46 and page 4 / register 47
0x0000
FIR17
Page 4 / register 48 and page 4 / register 49
0x0000
FIR18
Page 4 / register 50 and page 4 / register 51
0x0000
FIR19
Page 4 / registe 52 and page 4 / register 53
0x0000
FIR20
Page 4 / register 54 and page 4 / register 55
0x7FFF (decimal 1.0 – LSB value)
FIR21
Page 4 / register 56 and page 4 / register 57
0x0000
FIR22
Page 4 / register 58 and page 4 / register 59
0x0000
FIR23
Page 4 / register 60 and page 4 / register 61
0x0000
FIR24
Page 4 / register 62 and page 4 / register 63
0x0000
5.5.4.4
ADC Digital Decimation Filter Characteristics
The TLV320AIC3111 offers three different types of decimation filters. The integrated digital decimation
filter removes high-frequency content and downsamples the audio data from an initial sampling rate of
AOSR × fS to the final output sampling rate of fS. The decimation filtering is achieved using a higher-order
CIC filter followed by linear-phase FIR filters. The decimation filter cannot be chosen by itself; it is implicitly
set through the chosen processing block.
The following subsections describe the properties of the available filters A, B, and C.
Copyright 2009, Texas Instruments Incorporated
APPLICATION INFORMATION
35