Motorola DSP56305 Manuel d'utilisateur télécharger pdf (Page 50)

MOTOROLA Optimizing DSP56300/DSP56600 Applications 4-1

This section

describes the main

DMA features and

how they can be

used to enhance

performance.

Section 4

USING THE DMA

4.1 INTRODUCTION

The DSP56300 DMA is a powerful functional block for moving data.

It has special registers and data paths that enable it to perform

various transfer tasks without stalling the core. It's main features

are:

• Parallel operation with the core

• Complex address calculation modes

• Transfer triggered by peripheral events, external interrupts

or software

• Transfer end may trigger other transfers or interrupt the core

• Transfer modes support flexible triggering for “words”,

“lines” and “blocks”

This section provides some application examples for using the

DMA functions. It assumes basic familiarity with the DMA. For

detailed information about the DMA see Section 8 of the

DSP56300 Family Manual

Note: Although may of the DMA registers can be used as general

purpose registers if not otherwise used, do not use the

control registers for general purpose data, otherwise an

accidental activation of a transfer may result.

4.2 CONSERVING CORE MIPS BY WORKING IN

PARALLEL

The DMA has data and address busses that are separate from the

core and independent address generation capability. This enables it

to work completely in parallel with the core, as long as the DMA

unit and the core do not contend for the same resource.

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Motorola DSP56305 Manuel d'utilisateur Page 50