HP 54501A - Interface Functions; Introduction; Interface Capabilities; Addressing

Interface
Functions
2
Introduction
This
section
describes
the
interface functions
and
some
general
concepts
of
the
HP-IB.
In
general,
these functions
are
defined
by
IEEE
488.1.
They
deal
with
general
bus
management
issues,
as
well
as
messages
which
can
be
sent
over
the bus
as
bus
commands.
Interface
Capabilities
The
interface
capabilities
of the
HP
54501A,
as
defined by
IEEE 488.1
are
SH1,
AH1,
T5, L4,
SRI,
RL1,
PP1,
DC1,
DT1,
CO,
and
E2.
Command
and
Data
Concepts
The
HP-IB
has
two
modes
of
operation:
command
mode
and data
mode.
The bus
is
in
command
mode
when
the
ATN line
is
true.
The
command
mode
is
used
to
send
talk
and
listen
addresses
and
various
bus
commands,
such
as
a
group
execute
trigger
(GET).
The
bus
is
in
the
data
mode when
the
ATN
line
is
false.
The
data
mode
is
used
to
convey
device-dependent
messages across
the
bus.
The
device-dependent messages
include
all
of
the
instrument
command
and
responses
found
in
chapters
5
through 17
of
this
manual.
Addressing
By
using
the
front-panel
controls,
the
instrument can
be
placed
in
either
talk-only mode
or
addressed
(talk/listen)
mode
(see
your
front-panel
reference).
Talk-only
mode
should
be
used
when
you want
the
instrument
to
talk
directly
to
a
printer
without
the
aid
of
a
controller.
Addressed
mode
is
used
when
the
instrument
will
operate
in
conjunction
with
a
controller.
When
the
instrument
is
in the
addressed
mode,
the
following
is
true:
HP
54501A
Programming
Interface
Functions
2-1