UT1750AR(2003) View Datasheet(PDF) - Aeroflex UTMC

Part Name

Description

Manufacturer

UT1750AR
(Rev.:2003)

RadHard RISC Microprocessor

Aeroflex UTMC 

OSCIN

CK1

CK2

CK3

CK4

STATE1

OE

WE

RISC

ADDRESS

RISC

DATA

ADDRESS VALID (ACC)

ADDRESS VALID (IC)

DATA VALID

DATA VALID (RSn)

DATA VALID

Figure 29. LRI Instruction Typical Timing

INTERNAL UART OPERATION

The UT1750AR has an internal UART. Figure 30 (see page 30)

shows a diagram of the UT1750AR connected to a serial data

bus. The UART operates at a fixed frequency of 9600 baud with

eight data bits, one stop bit, and odd parity. The TIMCLK input

fixes the baud rate of the UART. This input also controls the

frequency of the internal 1750 timer registers (TA and TB).

The UART’s Transmitter Buffer Register (TXMT) and

Receiver Buffer Register (RCVR) are UT1750AR internal

registers and are treated as such when programming the

UT1750AR. The status of the UT1750AR’s internal UART is

read from the System Status Register (STATUS) bits 7 through

0.

UART Transmitter Operation

The transmitter portion of the UT1750AR’s UART is a double-

buffered configuration consisting of a Transmitter Register and

a Transmitter Buffer Register. The Transmitter Register

contains the serial data stream the UT1750AR is currently

transmitting through the UART; the Transmitter Buffer Register

contains the next message to transmit through the UART. The

system programmer reads the status of the Transmitter Register

from bit 1 (TE) of the STATUS and the status of the Transmitter

Buffer Register from bit 2 (TBE) of the STATUS. If bit 2 of the

STATUS is high, the UART transmitter is ready for data. Bit 1

is low during the serial transmission and transitions to a high

when a transmission from the Transmitter Register is complete.

To initiate a serial data transmission, the system designer must

first load the data to transmit into the Transmitter Buffer

Register with the output instruction. This instruction loads the

least significant byte of the source register specified in the

instruction into the Transmitter Buffer Register. At this time,

TBE goes low and the UT1750AR automatically transfers the

data word into the Transmitter Register. After the transfer is

complete, TE goes low and TBE returns high indicating a serial

transmission is about to begin and the next data word can be

loaded into the Transmitter Buffer Register.

29

Share Link: