Cirrus’ CS485xx series (S48520, CS48540 and CS48560) digital audio 32-bit DSP provides high-performance post-processing and mixing of digital audio at different sampling rates. The DSP can perform 300,000,000 multiply and accumulate operations per second (MAC), with Industry’s most accurate 72-bit accumulator, 24k x 32 SRAM, 192 kHz SPDIF transmitter, 1.8V core single voltage and 5V compatible 3.3VI/O voltage. Mainly used in car audio systems, DTV, HD-DVD and Blu-ray DVD Players and PC speakers. This article introduces the main features of the CS485xx series, the system block diagram and the CDB48500-USB evaluation board main features, block diagrams and detailed circuit diagrams.
The CS485xx DSP Family is designed to provide high-performance post-processing and mixing of digital audio. The dual clock domain provided on the PCM inputs allows for the mixing of audio streams with different sampling frequencies. The low-power standby preserves battery life for applications which are always on, but not necessarily processing audio, such as automotive audio systems.
There are three devices comprising the CS485xx family. The CS48520, CS48540 and CS48560 are differentiated by the number of inputs and outputs available. All DSPs support dual input clock domains and dual audio processing paths. All DSPs are available in a 48-pin QFP package .
CS485xx 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 most accurate in the industry
— 24k x 32 SRAM, 2k blocks – assignable to data or program
— Internal ROM contains a variety of configurable sound enhancement feature sets
— 8-channel internal DMA
— Internal watch-dog DSP lock-up prevention
DSP Tool Set w/ Private Keys for Protecting Customer IP
Configurable Serial Audio Inputs/Outputs
— Configurable for all input/output types
— Maximum 32-bit @ 192 kHz
— Supports 32-bit audio sample I/O between DSP chips
— TDM input modes (multiple channels on same line)
— 192 kHz SPDIF transmitter
— Multi-channel DSD direct stream digital SACD input
Supports Two Different Input Fs Sample Rates
— Output can be master or slave
— Dual processing path capability
— Input supports dual domain slave clocking
— Hardware assist time sampling for sample rate conversion
Integrated Clock Manager/PLL
— Can operate from external crystal, external oscillator
Input Fs Auto Detection
Host & Boot via 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
— “Energy Star® Ready” in low-power mode, 268 μW in standby
Differentiating from the legacy Cirrus multi-standard, multichannel decoders, this new CS485xx family is still based on the same high-performance 32-bit fixed point Digital Signal Processor core but instead is equipped with much less memory, tailoring it for more cost-effective applications associated with multi-channel and virtual-channel sound enhancements.
CS485xx series target applications:
— Digital Televisions
— Multimedia Peripherals
— iPod® Docking Stations
— Automotive Head Units
— Automotive Outboard Amplifiers
— HD-DVD & Blu-ray Disc DVD Receivers
— PC Speakers
Figure 1. CS48500 system block diagram
CDB48500-USB Evaluation Board
Each CDB48500-USB kit comes with the following:
• CDB48500 Development Board (See Figure 1-2)
• Power Supply: +9V, 1.67A, 100V – 240V, with AC Power Cord
• CDB USB MASTER Digital I/O Card (See Figure 1-2)
• USB Cable
• 3 Board Overlays Identifying the Outputs for CS48520, CS48540, and CS48560
• Document Card Explaining How to Get the Latest Board Software
The CDB48500-USB is a convenient and easy-to-operate evaluation platform. It has been designed to demonstrate the majority of the CS485XX functions on a small 6″ x 6.5″ base board.
CDB48500-USB Evaluation Board Features:
• PC control of the CS485XX using the DSP Composer™ graphical user interface
• Serial control of audio devices on CDB48500 via I2C® or SPI™ protocols
• Digital audio input of PCM via optical or coaxial S/PDIF (does not support compressed data input)
• Up to 12-channel analog audio input via the two CS42448 audio codecs
• Up to 12-channel analog output through the two CS42448 audio codecs
• Digital audio output of PCM data via optical S/PDIF
• Headphone output jack
• Multi-channel digital audio input via the CDB USB MASTER card (not yet supported)
• Separate input and output clocking domains to allow 1FS-to-2FS audio processing on the CS485XX
• Fast boot – host-controlled master boot (HCMB) of custom applications from 4 Mbit serial SPI flash device.
• Microphone input with integrated amplifier for Intelligent Room Calibration (IRC) evaluation (future)
• Supports all members of the CS485XX family in the 48-pin LQFP package.
Figure 2. CDB48500-USB Evaluation Board Block Diagram
Figure 3. CDB48500-USB Evaluation Board Outline Drawing
Figure 4. CDB48500-USB Evaluation Board Connection Diagram
Figure 5. CDB48500-USB Evaluation Board Block Diagram
Figure 6. CDB48500-USB Evaluation Board Circuit Diagram: DSP Input Data Multiplexing Circuit
Figure 7. CDB48500-USB Evaluation Board Circuit Diagram: DSP Circuit
Figure 8. CDB48500-USB Evaluation Board Circuit Diagram: Serial Flash Memory Circuit
Figure 9. CDB48500-USB Evaluation Board Circuit Diagram: SPDIF Receiver Circuit
Figure 10. CDB48500-USB Evaluation Board Circuit Diagram: CODEC #1 (CS42448) Circuit
Figure 11. CDB48500-USB Evaluation Board Circuit Diagram: CODEC #2 (CS42448) Circuit
Figure 12. CDB48500-USB Evaluation Board Circuit Diagram: CODEC #1 (CS42448) Circuit
Figure 13. CODEC 1 and CODEC 2 Input Filter Circuit Diagram
Figure 14. CDB48500-USB output filter and headphone output circuit diagram
Figure 15. CDB48500-USB Evaluation Board Circuit Diagram: Microphone Preamplifier Circuit
Figure 16. CDB48500-USB Evaluation Board Circuit Diagram: Control Connections and Power Circuitry
For details, see:
http://www.cirrus.com/en/pubs/proDatasheet/CS485xx_F4.pdf
and
http://www.cirrus.com/en/pubs/rdDatasheet/CDB48500-USB_Guide_DB1.pdf
The Links: FZ900R12KF5 QF30AA60
