EVAL-ADAU1446EBZ Analog Devices Inc, EVAL-ADAU1446EBZ Datasheet - Page 16

• Manufacturer Part Number: EVAL-ADAU1446EBZ
• Description: Evaluation BD 175MHZ SigmaDSP,8x2 SRCs
• Manufacturer: Analog Devices Inc
• Series: SigmaDSP®r

Specifications of EVAL-ADAU1446EBZ

• Main Purpose: Audio, Audio Processing
• Embedded: Yes, DSP
• Utilized Ic / Part: ADAU1446
• Primary Attributes: 28/56-bit, Audio DSP, Single-chip, Multichannel
• Secondary Attributes: I²C & SPI Interfaces
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADAU1445/ADAU1446
OVERVIEW
The ADAU1445/ADAU1446 are each a 24-channel audio DSP with
an integrated S/PDIF receiver and transmitter, flexible serial audio
ports, up to 16 channels of asynchronous sample rate converters
(ASRCs), flexible audio routing, and user interface capabilities.
Signal processing capabilities include equalization, crossover,
bass enhancement, multiband dynamics processing, delay com-
pensation, speaker compensation, and stereo image widening.
These algorithms can be used to compensate for the real-world
limitations of speakers, amplifiers, and listening environments,
resulting in an improvement in perceived audio quality.
An on-board oscillator can be connected to an external crystal
to generate the master clock. A phase-locked loop (PLL) allows
the ADAU1445/ADAU1446 to be clocked from a variety of clock
frequencies. The PLL can accept inputs of 64 × f
384 × f
where f
mode. In dual or quad rate mode, these multipliers are halved
or quartered, respectively. System sample rates include, but are
not limited to, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, and 192 kHz.
Each ADAU1445/ADAU1446 operates from a 1.8 V digital power
supply and a 3.3 V analog supply. An on-board voltage regulator
can be used to operate the chip from a single 3.3 V supply.
The ADAU1445/ADAU1446 have a sophisticated control port
that supports complete read and write capability of all memory
locations, excluding read-only addresses. Control registers are
provided to offer complete control of the chip’s configuration
and serial modes. Handshaking is included for ease of memory
uploads and downloads. The ADAU1445/ADAU1446 can be
configured for either SPI or I
RAM, and register contents can be saved in an external EEPROM,
from which the ADAU1445/ADAU1446 can self-boot on startup.
The ADAU1445/ADAU1446 serial ports operate with digital audio
I/Os in the I
mode. The flexible serial data ports allow for direct interconnection
to a variety of ADCs, DACs, and general-purpose DSPs. The
combination of an on-board S/PDIF transmitter and receiver
and 16 channels of ASRCs allows for easy compatibility with an
extensive number of external devices, and a system with up to
nine sampling rates.
The flexible audio routing matrix (FARM) is a system of multi-
plexers used to distribute the audio signals in the ADAU1445/
ADAU1446 among the serial inputs and outputs, audio core,
and ASRCs. FARM can easily be configured by setting the
appropriate registers.
The ADAU1445 and ADAU1446 are distinguished by the number
of on-board ASRCs and maximum sample rates. The ADAU1445
contains two 8-channel ASRCs, and the ADAU1446 has no ASRCs.
Two sets of serial ports at the input and output can operate in a
special flexible TDM mode, which allows the user to independently
S
S
, or 512 × f
is the sampling rate of audio in normal-rate processing
2
S, left-justified, right-justified, or TDM-compatible
S
to generate the internal master clock of the core,
2
C control. Program RAM, parameter
S
, 128 × f
S
, 256 × f
Rev. A | Page 16 of 92
S
,
assign byte-specific locations to audio streams at varying bit
depths. This mode ensures compatibility with codecs using
similar flexible TDM streams.
The core of the ADAU1445/ADAU1446 is a 28-bit DSP (or a
56-bit DSP when using double-precision mode) optimized for
audio processing, and it can process audio at sample rates of up
to 192 kHz. The program and parameter RAMs can be loaded with
a custom audio processing signal flow built with the SigmaStudio
graphical programming software from Analog Devices, Inc. The
values stored in the parameter RAM control individual signal pro-
cessing blocks, such as IIR and FIR equalization filters, dynamics
processors, audio delays, and mixer levels. A software safeload
feature allows for transparent parameter updates and prevents
clicks on the output signals.
Reliability features such as a CRC and program counter watchdog
help ensure that the system can detect and recover from any
errors related to memory corruption.
S/PDIF signals can be routed through an ASRC for processing
in the DSP or can be sent directly to output on MP pins for
recovery of the embedded audio signal. Other components of
the embedded signal, including status and user bits, are not lost
and can be output on the MP pins as well.
Multipurpose (MP) pins are available for providing a simple
user interface without the need for an external microcontroller.
Twelve pins are available to input external control signals and
output flags or controls to other devices in the system. Four of
these can alternatively be assigned to an auxiliary ADC for use
with analog controls such as potentiometers or system voltages.
As inputs, MP pins can be connected to push buttons, switches,
rotary encoders, potentiometers, or other external control circuitry
to control the internal signal processing program. When con-
figured as outputs, these pins can be used to drive LEDs (with a
buffer), to output flags to a microcontroller, to control other ICs,
or to connect to other external circuitry in an application.
The SigmaStudio software is used to program and control the
ADAU1445/ADAU1446 through the control port. Along with
designing and tuning a signal flow, the software can configure
all of the DSP registers in real time and download a new program
and parameter into the external self-boot EEPROM. SigmaStudio’s
easy-to-use graphical interface allows anyone with audio processing
knowledge to easily design a DSP signal flow and port it to a target
application without the need for writing line-level code. At the
same time, the software provides enough flexibility and program-
mability for an experienced DSP programmer to have in-depth
control of the design. In SigmaStudio, the user can add signal
processing cells from the library by dragging and dropping cells,
connect them together in a flow, compile the design, and load
the program and parameter files into the ADAU1445/ADAU1446
memory through the control port. The complicated tasks of
linking, compiling, and downloading the project are all handled
automatically by the software.