Cirrus公司的CS470xx系列是高性能后处理以及混合模拟和数字音频的音频系统级芯片(ASOC).具有高性价比的32位DSP, 300,000,000 MAC/S(每秒乘发运算),业界精度最高的72位居累加器,双路时钟域支持DAI和SPDIF RX一起输入,集成的取样速率转换器(SRC)允许音频流以不同的确取样速率混合.集成的8路24位DAC的动态范围(DR)为108dB,THD+N为-98dB,4路24位ADC的DR为105dB,THD+N为-98dB,主要用于汽车音频放大器,汽车处理器,DTV,MP3坞站,AVR和DVD RX, DSP控制的扬声器.本文介绍了CS470xx 系列主要特性,方框图,CDB47xxxS主板方框图,电路图与主要元件, CDB47xxx-DC48子板方框图,电路图与主要元件.
The CS470xx DSP is designed to provide high-performance post-processing and mixing of analog and digital audio. Dual clock domains are supported when the DAI and SPDIF RX inputs are used together. Integrated sample rate converters (SRCs) allow audio streams with different sample rates to be mixed. The low-power standby preserves battery life for applications that are always on, but not necessarily processing audio, such as automotive audio systems.
The CS470xx family is a new generation of audio system-on-a-chip (ASOC) processors targeted at high fidelity, cost sensitive designs. Derived from the highly successful CS48500 32-bit fixed-point audio enhancement processor family, the CS470xx further simplifies system design and reduces total system cost by integrating the S/PDIF Rx, S/PDIF Tx, analog inputs, analog outputs, and SRCs. For example, a hardware SRC can down-sample a 192 kHz S/PDIF stream to a lower Fs to reduce memory and MIPS requirements for processing. This integration effectively reduces the chip count from 3 to 1, which allows smaller, less expensive board designs.

CS470xx 系列典型应用:
 Automotive head units and outboard amplifiers
 Automotive processors and automotive integration hubs
 Digital TV
 MP3 docking stations
 AVR and DVD RX
 DSP controlled speakers (subwoofers, sound bars)
The CS470xx is programmed using the simple yet powerful Cirrus proprietary DSP Composer™ GUI development and pre-production tuning tool. Processing chains can be designed using a drag-and-drop interface to place/utilize functional macro audio DSP primitives and custom audio filtering blocks. The end result is a software image that is downloaded to the DSP via serial control port.
The Cirrus Framework™ programming environment offers Assembly and C language compilers and other software development tools for porting existing code to the CS470xx family platform.
The CS470xx is available in a 100-pin LQFP package with exposed pad for better thermal characteristics. Both Commercial (0°C to +70°C) and Automotive (–40℃ to +85℃) temperature grades.

CS470xx 系列主要特性:
 Cost-effective, High-performance 32-bit DSP
 300,000,000 MAC/S (multiply accumulates per second)
 Dual MAC cycles per clock
 72-bit accumulators are the highest precision in the industry
 32K x 32-bit SRAM with three 2K blocks assignable to either Y data or program memory
 Integrated DAC and ADC Functionality
 8† Channels of 24-bit DAC output: 108dB DR, –98 dB THD+N
 4† Channels of 24-bit ADC input: 105dB DR, –98 dB THD+N
 Integrated 5:1 analog mux feeds one stereo ADC
 Configurable Serial Audio Inputs and Outputs
 Integrated 192 kHz S/PDIF Rx
 Integrated 192 kHz S/PDIF Tx
 Supports 32-bit serial data @ 192 kHz
 Supports 32-bit audio sample I/O between DSP chips
 TDM I/O modes
 Supports Different Sample Rates (Fs)
 Three integrated hardware SRC blocks
 Output can be master or slave
 Supports dual-domain Fs on S/PDIF vs. I²S inputs
 DSP Tool Set with Private Keys Protect Customer IP
 Integrated Clock Manager/PLL
 Flexibility to operate from internal PLL, external crystal, external oscillator
 Input Fs Auto Detection w/ μC Acknowledgement
 Host Control and Boot via I²C™ or SPI™ Serial Interface
 Configurable GPIOs and External Interrupt Input
 1.8V Core and a 3.3V I/O that is tolerant to 5V input
 Low-power Mode

图1.CS47048方框图

图2.CDB47xxxS-DCxx开发套件外形图

图3.CDB47xxxS主板方框图

图4.CDB47xxx-DC48子板方框图

图5.CDB47xxx-DC28子板方框图

图6.CDB47xxxS (单端)主板外形图:顶视图

图6 CDB47xxxS (单端)主板对应的元件:
1. +9V Power In
2. Optical S/PDIF Out
3. Coax S/PDIF Out
4. Optical S/PDIF In
5. Coax S/PDIF In
6. +5V Header
7. Line-Level Analog Outputs
8. CDB47xxS-DC48 Daughtercard Connectors
9. Mic Input
10. Single-Ended Line-Level Inputs
11. MCU Rotary Encoder
12. MCU Buttons
13. SPI Flash
14. I2C EEPROM
15. LCD
16. DSP DAO Header
17. IR Receiver
18. Board Reset
19. MCU Programming Header
20. MCU Control Bypass Header
21. USB Connector
22. DSP External Control Header
23. DSP DAI Header
24. +1.8V Header
25. Power LEDs (4)
26. + 3.3V Header

图7.CDB47xxx-DC48 子板外形图:顶视图

图7 CDB47xxx-DC48 子板岁对应的元件:
1. Cirrus Logic CS47048 DSP
2. Power LEDs (2)
3. MCLK-XTAL_OUT Header
4. DSP GPIO Button
5. DSP GPIO LED
6. DSP GPIO LED
7. DSP GPIO Switch
8. +1.8VD Probe Point
9. +3.3VD Probe Point
10. +1.8VA Probe Point
11. +3.3VA Probe Point

图8.CDB47xxxS (单端)子板连接器电路图

图9.CDB47xxxS (单端)数字音频控制连接器电路图

图10.CDB47xxxS (单端)串行存储器电路图

图11.CDB47xxxS (单端)麦克风前置放大器电路图

图12.CDB47xxxS (单端)电源连接器电路图

图13.CDB47xxxS (单端)ADC滤波器电路图

图14.CDB47xxxS (单端)DAC滤波器电路图

图15.CDB47xxxS (单端)MCU卡接口电路图

图16.CDB47xxxS (单端)MCU卡用户接口电路图(1)

图17.CDB47xxxS (单端)MCU卡用户接口电路图(2)

图18.CDB47xxx-DC48子板框图

图19.CDB47xxx-DC48子板电路图