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S E C T I O N
I V
R E M O T E
O P E R A T I O N
4 - 1 .
IEE-488 INTERFACE
functions to perform.
The IEEE-488 INTERFACE is an in-
The interface works on a party line
strumentation bus with hardware and
basis with all devices on the bus
programming standards designed to
connected in parallel.
All the
simplify instrument interfacing.
active circuitry of the bus is
The IEEE-488 INTERFACE of the DRC-
contained within the individual devices
93C
fully
complies with
the
with the cable connecting all the
IEEE-488-1978 standard and incor-
devices in parallel to allow the
porates the functional, electrical
transfer of data between all devices
and mechanical specifications of
on the bus.
the standard. It also follows the
supplement to that standard titled
The following discussion of the
"Code and Format Conventions for
signal lines on the bus are for
use with IEEE Standard 488-1978".
general information.
Your digital
This section contains general bus
computer handles these lines through
information, Model DRC-93C interface
its circuitry and software. The user
capabilities, addressing and
the
need never concern himself with
programming
instructions that
these lines or signals, however,
control the DRC-93C functions.
knowledge of their purpose will
help one to understand the operation
4 - 2
GENERAL
I E E SPECIFICATIONS
of the Interface.
There are
1 6
signal lines contained
on the bus:
AND OPERATION
The following discussion covers the
general operation of the IEEE-488
interface.
For a more detailed
1 . 8
Data Lines
description of signal level and
2.
3
Transfer Control Lines
interaction, refer to the IEEE
3.
5
General Interface Management
Standard
488-1978
publication "IEEE
Lines
Standard
Digital Interface
for
Programmable Instrumentation".
The data lines consist of
8
signal
lines that carry data in a bit
All instruments on the interface
parallel, byte
serial
format.
bus must be able to perform one or
These lines carry universal commands,
more of the interface functions of
addresses, programdata, measurement
TALKER, LISTENER, or BUS CONTROLLER.
data and status to all the devices
A TALKER transmits data onto the
on the bus.
bus to other devices.
A LISTENER
receives data from other devices
The three Transfer Control lines
through the bus.
The BUS CONTROLLER
and the five Interface Management
designates to the devices on the
lines are asserted low which means
bus which function to perform.
that they carry out their function
when pulled low.
When the voltage
The DRC-93C performs the functions
on one of these lines is high then
of TALKER and LISTENER but cannot
the line is not asserted and the
be a BUS
CONTROLLER.
The
B U S
function is inhibited. The General
CONTROLLER is your Digital Computer
Interface Management Lines
IFC
which
tells the DRC-93C which
(Interface Clear), ATN (Attention),
COPYRIGHT
3/88
LSCI
4-1
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