Datasheet
Audio Input Ports
3-7
3.3 Audio Input Ports
The SRC4192EVM includes four audio input ports, two each for the SRC A and
SRC B sections of the SRC4194. Each section is provided with an
AES3/SPDIF-compatible input, along with a buffered I/O header. Figure 3−2
illustrates the input port external connections and associated switch settings.
Figure 3−2. Input Port External Connections and Configuration
Switch SW6 or SW8
x_IM/S
LO = SRC is Slave
HI = SRC is Master
Switch SW6 or SW8
x_DIR
LO = Output Enabled
HI = Output Disabled
BCKx
LRCKx
SDINx
SCK
FSYNC
SDATA
RCKIx
RCKIx
SDINx
LRCKx
BCKx
NOTE: x = A or B
INPUT PORT A (J5)
or
INPUT PORT B (J10)
2
1
U1
SRC4194IPAG
U14 or U24
CS8414−CS
From
RCKIx
Source
The SRC A section input port selection and Master/Slave mode operation are
configured using the A_DIR and A_IM/S elements of switch SW6. The SRC
B section input port selection and Master/Slave mode operation are config-
ured using the B_DIR
and B_IM/S elements of switch SW8.
The AES IN A (J6) and AES IN B (J11) connectors accept 75Ω coaxial cable
connections terminated with RCA plugs. The onboard AES3 receivers (U14
and U24) recover audio clocks and data from the AES3 encoded input stream.
The receivers are configured to output 24-bit I
2
S-formatted audio data with a
serial bit (or data) clock rate of 64f
s
and a left/right word clock rate of f
s
, where
f
s
is the frame or sampling rate of the incoming AES3-formatted data stream.
Sampling rates up to 108kHz are supported. The AES IN A and B input ports
provide a convenient, standard interface to consumer and professional audio
equipment, as well as common audio test systems.
The buffered input serial ports INPUT PORT A (J5) and INPUT PORT B (J10)
support Left-Justified, Right-Justified, and I
2
S-formatted audio data with word
lengths up to 24 bits and sampling rates up to 212kHz. The input ports may
be operated in either Slave or Master mode, but must match the input port set-
up for the SRC4194 device, as defined in Table 3−3. The buffered serial input
ports provide a convenient method for interfacing to audio devices that support
an audio serial data interface, including external digital audio receivers, audio
data converters, and digital signal processing components.