
DESCRIPTION OF THE AUDIOPROCESSOR
PART
Programmable Input Matrix
The programmable input matrix of the TDA7461N
offers several possibilities to adapt the audioproc-
essor to the desired application. In to the stand-
ard application we have:
CD quasi differential
Cassette stereo
Phone differential
AM mono
Stereodecoder input.
The input matrix can be configured by only 2 bits:
bits 3 and 4 of subaddress 0. Basically the bit of
subaddress 13 is fixed by the application and has to
be programmed only once at the startup of the IC.
For many configurations the two bits are also fixed
during one application (e.g. the standard applica-
tion) and a change of the input source can be done
by loading the first three bits of subaddress 0.
In other configurations for some sources a pro-
gramming of bit 3 and 4 of subaddress 0 is nec-
essary in addition to the three source selection
bits. In every case only the subaddress 0 has to
be changed to switch from one source to another.
The following picture shows the input and source
programming flow:
TDA7461
CD QD
CD FD
APPL. 2
APPL. 1
APPL. 3
APPL. 5
APPL. 4
APPL. 6
CD QD
CASSETTE
FM STD
AM MONO
PHONE (D)
CD QD
CASSETTE
FM STD
AM STEREO
PHONE (SE)
CD QD
CASSETTE
FM STD
AM STD
PHONE (D)
CD FD
CASSETTE
FM STD
AM MONO
PHONE (SE)
CD FD
CASSETTE
FM STD
AM STEREO
CD FD
CASSETTE
FM STD
AM STD
PHONE (SE)
D97AU632B
Figure 1. Input Configuration Tree
Note: in AMSTD configuration the AM mono signal is lead through the FM stereodecoder part to use its additional filters and high-cut function.
PIN NUMBER
Appl. No
6
8
9
10
Programming
1)
1CDGND
PhoneGND
Phone
AMMONO
Startup:
0/xxx11xxx
2CDGND
PhoneGND
AMRIGHT
AMLEFT
Startup:
0/xxxx1xxx
FM
AM
Phone
0/xxx11100
0/xxx01011
0/xxx11010
3CDGND
PhoneGND
Phone
AMSTD
Startup:
0/xxxx1xxx
FM
AM
Phone
0/xxx11100
0/xxx01100
0/xxx11010
4
CDRGND
CDLGND
Phone
AMMONO
Startup:
0/xxxx0xxx
5
CDRGND
CDLGND
AMRIGHT
AMLEFT
Startup:
0/xxxx0xxx
FM
AM
0/xxx10100
0/xxx00011
6
CDRGND
CDLGND
Phone
AMSTD
Startup:
0/xxxx0xxx
FM
AM
Phone
0/xxx10100
0/xxx00100
0/xxx10010
1) Syntax 0/xxx11100 means: SUBADDRESS = 0 - DATA BYTE = xxx11100 (x - don’t care)
TDA7461N
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