DSP56857 datasheet(303/662 Pages) FREESCALE

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Features

Enhanced Synchronous Serial Interface (ESSI), Rev. 4

Freescale Semiconductor

12-3

12.1 Introduction

This chapter describes the Enhanced Synchronous Serial Interface (ESSI), discusses the

architecture, the programming model, the operating modes, and the initialization of the ESSI. The

ESSI is a full-duplex, serial port designed to allow Digital Signal Controllers (DSCs) to

communicate with a variety of serial devices, including industry-standard codecs, other DSCs, and

microprocessors. It is typically used to transfer samples in a periodic manner. The ESSI consists

of independent transmitter and receiver sections with independent clock generation and frame

synchronization.

12.2 Features

ESSI capabilities include:

•

Independent (asynchronous) or shared (synchronous) transmit and receive sections with

separate or shared internal/external clocks and frame syncs

•

Normal mode operation using frame sync

•

Network mode operation allowing multiple devices to share the port with as many as 32 time

slots

•

Network mode enhancements

— time slot mask registers (receive and transmit)

— end of frame interrupt

•

Programmable internal clock divider

•

Programmable word length (8, 10, 12, or 16 bits)

•

Program options for frame sync and clock generation

•

ESSI power-down feature

•

Audio enhancements

— three transmitters per ESSI (six-channel surround sound possible, but requires two

ESSIs)

DSP56857 Datasheet(PDF) 303 Page - Freescale Semiconductor, Inc