UT1750AR12WCC Ver la hoja de datos (PDF) - Aeroflex UTMC

Número de pieza

componentes Descripción

Fabricante

UT1750AR12WCC

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: