ADI公司的ADAU1401是集成了两个ADC和四个DAC以及微控制器类的控制接口的SigmaDSP 28/56位音频数字信号处理器(DSP),信号处理包括均衡,音频混合,低音增强,多带动态处理,延迟补偿,扬声器补偿以及立体声图像加宽等,可以弥补真实扬声器,放大器的不足,从而改善听觉环境,提高音频质量.主要用在多媒体扬声器系统,MP3播放器扬声器,汽车音响,微型立体声,数字电视,音乐乐器等.本文介绍了ADAU1401主要特性, 功能方框图, 系统框图, 自举模式, I2C与SPI控制和电路图,以及评估板EVAL-ADAU1401AEBZ主要特性,框图,电路图和PCB元件布局图.
The ADAU1401 is a complete single-chip audio system with a 28-/56-bit audio DSP, ADCs, DACs, and microcontroller-like control interfaces. Signal processing includes equalization, cross over, bass enhancement, multiband dynamics processing, delay compensation, speaker compensation, and stereo image widening. This processing can be used to compensate for real-world limitations of speakers, amplifiers, and listening environments, providing dramatic improvements in perceived audio quality.
Its signal processing is comparable to that found in high end studio equipment. Most processing is done in full 56-bit, double precision mode, resulting in very good low level signal performance. The ADAU1401 is a fully programmable DSP. The easy to use SigmaStudio™ software allows the user to graphically configure a custom signal processing flow using blocks such as biquad filters, dynamics processors, level controls, and GPIO interface controls.
ADAU1401 programs can be loaded on power-up either from a serial EEPROM through its own self-boot mechanism or from an external microcontroller. On power-down, the current state of the parameters can be written back to the EEPROM from the ADAU1401 to be recalled the next time the program is run.
Two Σ-Δ ADCs and four Σ-Δ DACs provide a 98.5 dB analog input to analog output dynamic. Each ADC has a THD + N of −83 dB, and each DAC has a THD + N of −90 dB. Digital input and output ports allow a glueless connection to additional ADCs and DACs. The ADAU1401 communicates through an I2C® bus or a 4-wire SPI port.

ADAU1401主要特性:
28-/56-bit, 50 MIPS digital audio processor
2 ADCs: SNR of 100 dB, THD + N of −83 dB
4 DACs: SNR of 104 dB, THD + N of −90 dB
Complete standalone operation
Self-boot from serial EEPROM
Auxiliary ADC with 4-input mux for analog control
GPIOs for digital controls and outputs
Fully programmable with SigmaStudio graphical tool
28-bit × 28-bit multiplier with 56-bit accumulator for full double-precision processing
Clock oscillator for generating master clock from crystal
PLL for generating master clock from 64 × fS, 256 × fS, 384 × fS, or 512 × fS clocks
Flexible serial data input/output ports with I2S-compatible, left-justified, right-justified, and TDM modes
Sampling rates of up to 192 kHz supported
On-chip voltage regulator for compatibility with 3.3 V systems
48-lead, plastic LQFP

ADAU1401应用:
Multimedia speaker systems
MP3 player speaker docks
Automotive head units
Minicomponent stereos
Digital televisions
Studio monitors
Speaker crossovers
Musical instrument effects processors
In-seat sound systems (aircraft/motor coaches)

图1.ADAU1401功能方框图

图2.ADAU1401系统框图

图3.ADAU1401自举模式电路图

图4.ADAU1401 I2C控制电路图

图5.ADAU1401 SPI控制电路图

评估板EVAL-ADAU1401AEBZ
The EVAL-ADAU1401AEBZ is a platform that operates all of the ADAU1401A’s functions with a full range of analog and digital inputs and outputs. Digital I/O connections are available in both S/PDIF and 3-wire serial data formats. The DSP is controlled by the SigmaStudio™ software, which interfaces to the board through a USB connection. This evaluation board is powered by a single supply, which is regulated to the proper voltages on the board. The PCB is in a 6” × 6” 4-layer design, with a single ground plane and a single power plane on the inner layers.
The ADAU1401A can be controlled via the USBi interface control board connected to the I2C/SPI communications interface. On-board self-boot EEPROM is included for operating the board independently of the SigmaStudio software. Push-buttons, LEDs, potentiometers, and other interface options on the included GPIO board can be connected to the evaluation board to enable GPIO control.
The EVAL-ADAU1401AEBZ can also be used for evaluation of the pin-compatible ADAU1701 and ADAU1702 SigmaDSP®s. The differences between the ADAU1401A, ADAU1401, ADAU1701, and ADAU1702 are:
• The ADAU1701, ADAU1401A, and ADAU1401 have 1024 program RAM locations, while the ADAU1702 has 512 program RAM locations.
• The ADAU1701 has 2k words of data memory, while the ADAU1702 has 0.5k words of data memory.

评估包包括:
EVAL-ADAU1401AEBZ evaluation board
GPIO control board
USBi board
Universal power supply
Mini-USB cable
Evaluation board/software quick-start guide, including a download link for the SigmaStudio tools
ADAU1401A, ADAU1401, ADAU1701, and ADAU1702 SigmaDSP Evaluation Board
Full-Featured ADAU1401 SigmaDSP evaluation board that operates all of the ADAU1401/ADAU1701/ADAU1702’s functions with a full range of analog and digital inputs and outputs as well as a self-boot EEPROM.USBi, 6 V power supply and an attachable GPIO control board are included in the package.

图6.评估板EVAL-ADAU1401AEBZ外形图

图7.评估板EVAL-ADAU1401AEBZ框图

图8.评估板EVAL-ADAU1401AEBZ电路图

图9.评估板EVAL-ADAU1401AEBZ电路图:CPLD

图10.评估板EVAL-ADAU1401AEBZ电路图:模拟输入和输出滤波器

图11.评估板EVAL-ADAU1401AEBZ电路图:S/PDIF接收器和发送器

图12.评估板EVAL-ADAU1401AEBZ复位和USB电路图

图13.评估板EVAL-ADAU1401AEBZ电路图:多用图引脚接口

图13.评估板EVAL-ADAU1401AEBZ电路图:电源

图14.评估板EVAL-ADAU1401AEBZ电路图:GPIO板连接器

图15.评估板EVAL-ADAU1401AEBZ电路图:GPIO板控制

图16.评估板EVAL-ADAU1401AEBZ PCB元件布局图:顶层