Zilog Z16C35 Manuel d'utilisateur télécharger pdf (Page 51)

ISCC

User Manual

UM011002-0808

Chapter 4 Data Communication Modes

4.1 INTRODUCTION

The ISCC™ provides two independent full-duplex channels programmable for use in any

common asynchronous or synchronous data communication protocols. The data commu-

nication protocols handled by the SCC cell within the ISCC are:

•

Asynchronous Mode

•

Character-Oriented Mode

•

Monosynchronous

•

Bisynchronous

•

External Synchronous

•

Bit-Oriented Mode

•

SDLC

•

SDLC Loop Mode

4.1.1 General Description of the Transmitter

A block diagram of the transmitter is given in Figure 4-1. The transmitter has an 8-bit

Transmit Data register (WR8) loaded from the internal data bus and a Transmit Shift reg-

ister loaded from either WR6, WR7, or the Transmit Data register. In byte-oriented modes,

WR6 and WR7 can be programmed with sync characters

. In Monosync mode, an 8-bit or

6-bit sync character is used (WR6), whereas a 16-bit sync character is used (WR6 and

WR7) in Bisync mode. In bit-oriented synchronous modes, the flag contained in WR7 is

loaded into the Transmit Shift register at the beginning and end of a message.

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Zilog Z16C35 Manuel d'utilisateur Page 51