ADAV4622
Rev. B | Page 25 of 2
8
S/PDIF INPUT/OUTPUT
The S/PDIF output (SPDIF_OUT/SDO1) uses a multiplexer to
select an output from the audio processor or to pass through the
unprocessed SPDIF_IN signals, as shown in Figure 32. On the
ADAV4622, the S/PDIF inputs, SPDIF_IN0/SPDIF_IN1/
SPDIF_IN2/SPDIF_IN3/SPDIF_IN4/SPDIF_IN5/SPDIF_IN6,
are available on the SDIN3, LRCLK0, BCLK0, LRCLK1,
BCLK1, LRCLK2, and BCLK2 pins, respectively. It is possible to
have all seven S/PDIF inputs connected to different S/PDIF
signals at one time. A consequence of this setup is that none of
the LRCLKs and BCLKs are available for use with the digital
inputs SDIN0, SDIN1, SDIN2, and SDIN3. If there is only one
S/PDIF input in use, using the SDIN3 pin as the dedicated
S/PDIF input is recommended; this enables BCLK0/LRCLK0,
BCLK1/LRCLK1, and BCLK2/LRCLK2 to be used as the clock
and framing signal for the synchronous and asynchronous port.
If SDIN3 is used as an S/PDIF input, it should not be used
internally as an input to the audio processor because it contains
invalid data. Similarly, if BCLK or LRCLK are used as S/PDIF
inputs, they can no longer be used as the clock and framing
signals for SDIN0, SDIN1, SDIN2, and SDIN3. The S/PDIF
encoder supports only consumer formats that conform to
IEC-600958.
SDIN3 (SPDIF_IN0)
LRCLK0 (SPDIF_IN1)
BCLK0 (SPDIF_IN2)
LRCLK1 (SPDIF_IN3)
BCLK1 (SPDIF_IN4)
LRCLK2 (SPDIF_IN5)
BCLK2 (SPDIF_IN6)
SDO1 (SPDIF_OUT)
S/PDIF
ENCODER
0
706
8-
0
29
Figure 32. S/PDIF Output
HARDWARE MUTE CONTROL
The ADAV4622 mute input can be used to mute any of the
analog or digital outputs. When the MUTE pin goes low, the
selected outputs ramp to a muted condition. Unmuting is
handled in one of two ways and depends on the register setting.
By default, the MUTE pin going high causes the outputs to
immediately ramp to an unmuted state. However, it is also
possible to have the unmute operation controlled by a control
register bit. In this scenario, even if the MUTE pin goes high,
the device does not unmute until a bit in the control register is
set. This can be used when the user wants to keep the outputs
muted, even after the pin has gone high again, for example, in
the case of a fault condition. This allows the system controller
total control over the unmute operation.
Full details on register settings and operation of the mute function
are available upon request. Contact a local Analog Devices sales
representative for more details.
AUDIO PROCESSOR
The internal audio processor runs at 2560 × f
S
; at 48 kHz, this
is 122.88 MHz. Internally, the word size is 28 bits, which allows
24 dB of headroom for internal processing. Designed specific-
ally with audio processing in mind, it can implement complex
audio algorithms efficiently.
By default, the ADAV4622 loads a default audio flow, as shown
in Figure 34. However, because the audio processor is fully
programmable, a custom audio flow can be quickly developed
and loaded to the audio processor.
The audio flow is contained in program RAM and parameter
RAM. Program RAM contains the instructions to be processed
by the audio processor, and parameter RAM contains the
coefficients that control the flow, such as volume control, filter
coefficients, and enable bits.
GRAPHICAL PROGRAMMING ENVIRONMENT
Custom flows for the ADAV4622 are created in a powerful
drag-and-drop graphical programming application. No knowl-
edge of assembly code is required to program the ADAV4622.
Featuring a comprehensive library of audio processing blocks
(such as filters, delays, dynamics processors, and third-party
algorithms), it allows the quick and simple creation of custom
flows. For debugging purposes, run-time control of the audio
flow allows the user to fully configure and test the created flow.
Training materials and support are available upon request.
Contact a local Analog Devices sales representative for more
details.
APPLICATION LAYER
Unique to this family is the embedded application layer, which
allows the user to define a custom set of registers to control the
audio flow, greatly simplifying the interface between the audio
processor and the system controller.
Once a custom flow is created, a user-customized register map
can be defined for controlling the flow. Each register is 16 bits,
but controls can use only one bit or all 16 bits. Users have full
control over which parameters they control and the degree of
control they have over those parameters during run time. The
combination of the graphical programming environment and
the powerful application layer allows the user to quickly develop
a custom audio flow and still maintain the usability of a simple
register-based device.
Comprehensive documentation on developing a custom audio
flow and the definition and creation of the custom application
layer for the ADAV4622 is available upon request. Contact a
local Analog Devices sales representative for more details.
