CS485xx Family Data Sheet

32-bit Audio Decoder DSP Family

DS734F3

Copyright 2009 Cirrus Logic, Inc.

7

CONFIDENTIAL

4. Hardware Functional Description

4.1 DSP Core

The CS485xx family DSPs are single-core DSP with separate X and Y data and P code memory

spaces. The DSP core is a high-performance, 32-bit, user-programmable, fixed-point DSP that is

capable of performing two multiply-and-accumulate (MAC) operations per clock cycle. The DSP core

has eight 72-bit accumulators, four X- and four Y-data registers, and 12 index registers.

The DSP core is coupled to a flexible DMA engine. The DMA engine can move data between

peripherals such as the serial control port (SCP), digital audio input (DAI) and digital audio output

(DAO), or any DSP core memory, all without the intervention of the DSP. The DMA engine off loads

data move instructions from the DSP core, leaving more MIPS available for signal processing

instructions.

CS485xx family functionality is controlled by application codes that are stored in on-board ROM or

downloaded to the CS485xx from a host controller or external serial FLASH/EEPROM.

Users can develop their applications using DSP Composer to create the processing chain and then

compile the image into a series of commands that are sent to the CS485xx through the SCP. The

processing application can either load modules (matrix-processors, virtualizers, post-processors)

from the DSPs on-board ROM, or custom firmware can be downloaded through the SCP.

The CS485xx is suitable for a variety of audio post-processing applications such as automotive

head-ends, automotive amplifiers, and boom boxes.

4.1.1 DSP Memory

The DSP core has its own on-chip data and program RAM and ROM and does not require external

memory for post-processing applications.

The Y-RAM and P-RAM share a single block of memory that can be configured to make Y and P

equal in size, or more memory can be allocated for Y-RAM in 2kword blocks.

Table 2. Device and Firmware Selection Guide

Device

Suggested

Application

Channel Count

Input/Output

Package

CS48520-CQZ

Digital TV

Portable Audio Docking Station

Portable DVD

DVD Mini / Receiver

Multimedia PC Speakers

Up to 4 channel in / 4

channel out

48-pin QFP

CS48540-CQZ

CS48540-DQZ

CS48520 features Plus

8 Channel Car Audio

DVD Receiver

Up to 8 channel in / 8

channel out

48-pin QFP

CS48560-CQZ

CS48560-DQZ

CS48540 features Plus

12 channel Car Audio

High-end Digital TV

Dual Source/Dual Zone

SACD

Up to 12 channel in /12

channel out

48-pin QFP