Cirrus’ CS470xx series is a new generation of audio system-on-chip (ASOC) 32-bit processors with 300,000,000 multiplication operations per second (MAC/S) targeted for high-fidelity cost-sensitive designs. The series integrates S/ PDIF Rx, S/ PDIF Tx, analog input, analog output and sample rate converter (SRC), can simplify system design and reduce total system cost. Mainly used in car audio, DTV, MP3 docking station, AVR and DVD Rx, DSP Controlled speakers (sound bar, subwoofer). This article describes the main features of the CS470xx series, the CS47048 block diagram, the CDB47xxxD main and daughter board block diagrams and detailed circuit diagrams.

The CS470xx family is a new generation of audio system-on-a-chip (ASOC) targeted processors at high fidelity, cost sensitive designs. The CS470xx simplifies system design and reduces total system cost by integrating the S/PDIF Rx, S/PDIF Tx, analog inputs, analog outputs, and sample rate converters (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.

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 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 the 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℃ to +70℃) and Automotive (–40℃ to +85℃) temperature grades are available.

CS470xx series main features:

 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 DAC output: 108dB DR, –98dB THD+N

 4 Channels of ADC input: 105dB DR, –98dB 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 with μC Acknowledgement

 Host Control and Boot via I²C™ or SPI™ Serial Interface

 Configurable GPIOs and External Interrupt Input

 1.8V Core and a 3.3VI/O that is tolerant to 5V input

 Low-power Mode

CS470xx series target applications:

 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)

Figure 1. CS47048 block diagram

Figure 2. CDB47xxxD-DCxx development board outline drawing

Figure 3. CDB47xxxD motherboard block diagram

Figure 4. CDB47xxx-DC48 Daughter Board Block Diagram

Figure 5. CDB47xxD Differential Board Block Diagram

Figure 6. CDB47xxD (Differential) Daughter Board Connectors

Figure 7. CDB47xxD (Differential) Digital Audio Control Connector

Figure 8. CDB47xxD (Differential) Digital Serial Flash

Figure 9. CDB47xxD (Differential) Microphone Preamps

Figure 10. CDB47xxD (Differential) Power Connector

Figure 11. CDB47xxD (Differential) ADC Filter

Figure 12. CDB47xxD (Differential) Voltage Output Circuit

Figure 13. CDB47xxD (Differential) MCU Card Interface

Figure 14. CDB47xxD (Differential) MCU Card Circuit

Figure 15. CDB47xxD (Differential) MCU Card User Interface

Figure 16. CDB47xxx-DC48 Daughter Board Block Diagram

Figure 17. CDB47xxx-DC48 Daughter Board Circuit Diagram
For details, see:
http://www.cirrus.com/en/pubs/proDatasheet/CS470xx_F1.pdf
and
http://www.cirrus.com/en/pubs/manual/CDB470xx_UM_DB6.pdf