Conducting; Disabling Parallel Poll; Responses; Hp-Ib Commands - HP 54501A Programming Reference Manual

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