CS4614 データシートの表示（PDF） - Cirrus Logic

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CS4614

CrystalClear™ SoundFusion™ PCI Audio Accelerator

Cirrus Logic 

CS4614

CrystalClear™ SoundFusion™ PCI Audio Accelerator

management. This implementation improves sys-

tem efficiency by minimizing the number of host

interrupts.

The CS4614 supports a variety of audio I/O config-

urations including a CS4297 CrystalClear AC ’97

Codec. The system’s flexibility is further enhanced

by the inclusion of a bi-directional serial MIDI

port, a joystick port, a hardware volume control in-

terface, and a serial data port which allows connec-

tion of an optional external EEPROM device.

Stream Processor DSP Core

The CS4614 Stream Processor (SP) is a custom

DSP core design which is optimized for processing

and synthesizing digital audio data streams. The SP

features a Somewhat Long Instruction Multiple

Data (SLIMD) modified dual Harvard architecture.

The device uses a 40-bit instruction word and oper-

ates on 32-bit data words. The SP includes two

Multiply-Accumulate (MAC) blocks and one 16-

bit Arithmetic and Logic Unit (ALU). The SP core

is conservatively rated at 255 Million Instructions

per second (255 MIPS) when running at a 85 MHz

internal clock speed. The MAC units perform dual

20-bit by 16-bit multiplies and have 40-bit accumu-

lators, providing higher quality than typical 16-bit

DSP architectures.

A programmable Phase Locked Loop (PLL) circuit

generates the high frequency internal SP clock

from a lower frequency input clock. The input to

the PLL may be from a crystal oscillator circuit or

the serial port clock ABITCLK/SCLK. Clock con-

trol circuitry allows gating of clocks to various in-

ternal functional blocks to conserve power during

power conservation modes, as well as during nor-

mal modes of operation when no tasks are being

executed.

Legacy Support

Legacy games are supported by CrystalClear Leg-

acy Support (CCLS), DDMA, or by the PC/PCI in-

terface.

In both motherboard and add-in card designs,

CCLS and DDMA provide support for legacy

games by providing a hardware interface that sup-

ports a Sound Blaster Pro compatible interface, as

well as support for FM, MPU-401, and joystick in-

terfaces. These hardware interfaces provide PCI-

only games compatibility for real-mode DOS and

Windows DOS-box support.

For motherboard designs, PC/PCI can be used by

connecting the PCGNT# and PCREQ# pins to the

appropriate pins on the south bridge motherboard

chip. The PC/PCI interface is compliant with In-

tel’s PC/PCI spec. (version 1.2). The BIOS must

enable the PC/PCI mechanism at boot time on both

the CS4614 and the south bridge.

SYSTEM ARCHITECTURES

A typical system diagram depicting connection of

the CS4614 to the CrystalClear CS4297 AC ’97

Codec is given in Figure 7. All analog audio inputs

and outputs are connected to the CS4297. Audio

data is passed between the CS4297 and the CS4614

over the serial AC-Link. The CS4614 provides a

hardware interface for connection of a joystick and

MIDI devices.

HOST INTERFACE

The CS4614 host interface is comprised of two sep-

arate interface blocks which are memory mapped

into host address space. The interface blocks can be

located anywhere in the host 32-bit physical ad-

dress space. The interface block locations are de-

fined by the addresses programmed into the two

Base Address Registers in the PCI Configuration

Space. These base addresses are normally set up by

the system’s Plug and Play BIOS. The first inter-

face block (located by Base Address 0) is a 4 kByte

register block containing general purpose configu-

ration, control, and status registers for the device.

The second interface block (located by Base Ad-

dress 1) is a 1 MByte block which maps all of the

internal RAM memories (SP Program RAM, Pa-

10

CIRRUS LOGIC PRELIMINARY PRODUCT BULLETIN JUNE 30, 5:03 PM

DS292PP3

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