ZLR64400ROMMCU datasheet(53/155 Pages) ZILOG

53 / 155 page

PS024502-1205

P R E L I M I N A R Y

Operation

ZLR64400 ROM MCU

Product Specification

Operation

The UART channel can be used to communicate with a master microprocessor or as a

slave microprocessor, both of which exhibit transmit and receive functionality. A user can

either operate the UART channel by polling the UART Status register or via interrupts.

The UART remains active during HALT mode. If neither the transmitter nor the receiver is

enabled, the UART baud rate generator can be used as an additional timer. The UART

contains a noise filter for the receiver that can be enabled by the user.

Data Format

The UART always transmits and receives data in an 8-bit data format, with the least-sig-

nificant bit occurring first. An even or odd parity bit can be optionally added to the data

stream. Each character begins with an active Low Start bit and ends with either 1 or 2

active High Stop bits. Figures 14 and 15 illustrate the asynchronous data format employed

by the UARTs without parity and with parity, respectively.

Figure 13. UART Block Diagram

Receive Shifter

Parity Generator

Status Register

Transmitter Control

Transmit Shift

Receive Data

Transmit Data

Baud Rate

Generator

Control Registers

RxD

System Bus

TxD

ZLR64400ROMMCU Datasheet(PDF) 53 Page - Zilog, Inc.