HP 54501A - Conducting; Disabling Parallel Poll; Responses; HP-IB Commands

Conducting
a
Parallel
Poll
The
PPOLL
(Parallel Poll)
function
returns
a
single
byte
containing
up
to
8
status
bit
messages
for
all
devices
on
the bus
capable
of
responding
to
the
poll.
Each
bit
returned
by
the
function
corresponds
to
the
status
bit
of
the
devices(s) configured
to
respond
to
the
parallel poll
(one
or
more
devices
can
respond
on
a
single line).
The
PPOLL
function
can
only
be
executed
by
the
controller.
It
is
initiated
by
the
simultaneous
assertion
of
ATNandEOL
Example:
Response
=
PPOLL(7)
Disabling Parallel
Poll
Responses
The
PPU
(Parallel
Poll Unconfigure)
statement
gives
the
controller
the
capability
of
disabling
the
parallel poll
response
of
one
or
more
devices
on
the
bus.
Examples: The
following
statement
disables
device
five
only:
PPOLL
UNCONFIGURE
705
This
statement
disables
all
devices
on
interface
select
code
eight
from
responding
to
a
parallel
poll:
PPOLL
UNCONFIGURE
8
If
no primary
address
is
specified,
all
bus
devices
are
disabled
from
responding
to
a
parallel
poll.
If
a
primary
address
is
specified, only
the
specified
devices
(which
have
the
parallel
poll configure capability)
are
disabled.
HP-IB
Commands
The
following
paragraphs
describe
actual HP-IB
command
which
can
be
used
to
perform
the
functions
of
the
Basic
commands
shown
in the
previous
examples.
Parallel
Poll
Unconfigure
Command.
The
parallel
poll
Unconfigure
command
(PPU)
resets
all
parallel
poll
devices
to
the
idle
state
(unable
to
respond
to
a
parallel
poll).
Parallel
Poll
Configure
Command.
The
parallel poll configure
command
(PPC)
causes
the
addressed listener
to
be
configured according
to
the
parallel
poll
enable
secondary command
PPE.
HP
54501A
Programming
Message
Communication
and System
Functions
3-37