HELP
An object that captures asynchronous
interface events for VXI and HP-IB.  This
feature is available in HP VEE-Test only.

USE
The Interface Event object can be configured
to detect various interface events.
Depending on the configuration, the object
may wait for the event, giving up execution
to other parallel threads, or it may simply
return a boolean (0 or 1) or other indicator
of the state of the interface.

If the Interface Event object has been
configured to wait for the event, then upon
the event the object will execute.  Any
thread hosted by this object will have
priority over any other parallel threads, and
will execute to completion.  If the Interface
Event object has been configured to simply
return an indicator of interface state, the
thread containing it will have normal
priority, and will execute in parallel with
any other threads.

LOCATION
I/O ==> Advanced I/O ==> Interface Event

OPEN VIEW PARAMETERS

* Interface - The currently selected
interface is displayed in this field.  Click
on this field to display a list of the
currently configured interfaces.  For an
interface to appear in this list, at least
one device for that interface must be
configured using Config I/O.  Multiple
interfaces of the same type are distinguished
by the select code (e.g.:  "hpib7" and
"hpib8").

* Action - Determines the execution behavior
of the Interface Event object upon detection
of the event.

* Wait - Wait for the event to occur.  The
object will execute when the event occurs.
Any thread hosted by this object will have
priority over any other parallel threads, and
will execute to completion when the event
occurs, but is "blocked" until the event
occurs.  When the event occurs, a boolean
TRUE (1) or an interface-event-specific bit
pattern is output.

* No Wait - Execute immediately, placing the
current state of the configured event, as
specified by a 32-bit integer, on the event
output pin.  This value is the boolean value
FALSE (0) if the event has not occurred.  If
the event has occurred, a TRUE (1) or an
interface-event-dependent bit pattern is
returned.  In the No Wait configuration, any
thread hosted by the Interface Event object
will have normal execution priority, and will
execute in parallel with any other threads.

* Event - Allows selection of specific
interface events.  Click on this field to
display the choices.  For each choice below,
both the Wait and the No Wait actions are
described.  Note that in each case, the
thread propagation priorities for Wait and No
Wait are as described above.

* SRQ - This is the only choice for the HP-IB
interface:

-- If the Action choice is Wait, when an
HP-IB device "pulls" on the service request
line the Interface Event object will execute,
placing a boolean value TRUE (1) on the event
output pin.

-- If the Action choice is No Wait, a
boolean value FALSE (0) is output if the
event has not occurred.  If the event has
occurred, a boolean TRUE (1) will be output
on the event pin.

* Sys Reset - The Interface Event object will
execute when a system reset occurs on the VXI
interface:

-- If the Action choice is Wait, a boolean
TRUE (1) will be output on the event pin when
the system reset occurs.

-- If the Action choice is No Wait, a
FALSE (0) is output if the system reset has
not occurred.

* Sys Active - When the VXI Resource Manager
has finished its VXI initialization and
management, it sends a Begin Normal Operation
(BNO) command to the VXI interface.  If Sys
Active is configured, the Interface Event
object will execute when this occurs:

-- If the Action choice is Wait, a boolean
TRUE (1) will be output on the event pin when
the BNO command occurs.

-- If the Action choice is No Wait, a
FALSE (0) is output if the event has not
occurred.

* Sys Deactive - When normal VXI operation is
aborted an Abort Normal Operation (ANO) or
End Normal Operation (ENO) command is sent to
the interface.  If Sys Deactive is
configured, the Interface Event object will
execute when this occurs:

-- If the Action choice is Wait, a boolean
TRUE (1) will be output on the event pin when
the ANO or ENO command occurs.

-- If the Action choice is No Wait, FALSE
(0) is output if the event has not occurred.

* TTL Trig - When TTL Trig is configured, the
Interface Event object "monitors" the VXI TTL
trigger lines:

-- If the Action choice is Wait, the
Interface Event object executes when a VXI
device "pulls" on one or more of the eight
TTL trigger lines in the VXI backplane,
placing a 32-bit integer on the event output
pin.  Only the low byte of this integer is
significant.  It is a bit pattern showing
which of the eight TTL trigger lines are
active (bit 0 corresponds to trigger line 0,
bit 7, to trigger line 7).  Each bit set (1)
indicates that the corresponding line has
been triggered.  For example, 00010001
indicates that TTL lines 0 and 4 have been
triggered.

-- If the Action choice is No Wait, the
boolean FALSE (0) is output if no triggers
have occurred.

* ECL Trig - When ECL Trig is configured, the
Interface Event object "monitors" the VXI ECL
trigger lines:

-- If the Action choice is Wait, the
Interface Event object executes when a VXI
device "pulls" on one or more of the four ECL
trigger lines in the VXI backplane, placing a
32-bit integer on the event output pin.  The
low byte of this integer is a bit pattern
showing which of the four ECL trigger lines
are active.  (Bit 0 corresponds to trigger
line 0, bit 3, to trigger line 3.)  Each bit
set (1) indicates that the corresponding line
has been triggered.  For example, 00001001
indicates that ECL lines 0 and 3 have been
triggered.

-- If the Action choice is No Wait, the
boolean FALSE (0) is output if no triggers
have occurred.  Note that some VXI card cages
may choose to implement only two ECL trigger
lines.

* EXT Trig - When EXT Trig is configured, the
Interface Event object "monitors" the VXI EXT
trigger lines:

-- If the Action choice is Wait, the
Interface Event object will execute when an
external device "fires" on an embedded
controller's "Trig In" input.  Up to four
external trigger inputs can occur.  A 32-bit
integer is output on the event pin when the
Interface Event object executes.  The low
byte of this integer is a bit pattern showing
which of the four EXT trigger lines are
active.  (Bit 0 corresponds to external
trigger 0, bit 3, to external trigger 3.)
Each bit set (1) indicates that the
corresponding trigger has occurred.  For
example, 00001001 indicates that EXT trigger
lines 0 and 3 have been triggered.

-- If the Action choice is No Wait, the
boolean FALSE (0) is output if no triggers
have occurred.  Some controller
implementations may have no external trigger
inputs.  The HP 75000 Series C Model V382
embedded controller has one trigger input,
which corresponds to the least significant
bit of the returned 32-bit integer.

* Unknown Interrupt - If Unknown Interrupt is
configured, the Interface Event object checks
for any VME interrupts from a VME or VXI
device not in the VXI controller's servant
area:

-- If the Action choice is Wait, such an
interrupt will cause the Interface Event
object to execute.  The 32-bit value returned
is the value placed on the VXI Bus when the
device does an interrupt acknowledge (IACK).

-- If the Action choice is No Wait, the
boolean FALSE (0) is output if no interrupt
has occurred.

* Unknown Signal - If Unknown Signal is
configured, the Interface Event object checks
for any signal register write from a VXI
device not in the VXI controller's servant
area:

-- If the Action choice is Wait, such a
signal will cause the Interface Event object
to execute.  The 32-bit value returned is the
contents of the signal write register.

-- If the Action choice is No Wait, the
boolean FALSE (0) is output if no signal has
occurred.

NOTES
The execution behavior of the Interface Event
object can either be asynchronous or
synchronous, as determined by the choice of
the Action parameter.  NO WAIT specifies a
synchronous, polling behavior.  The object
executes immediately, and any attached thread
will have the same priority as all other
threads currently executing.  Choosing WAIT
causes the Interface Event object to wait
until the event has occurred.  Any thread
hosted by the object will have a higher
priority, and will execute to completion,
blocking all other concurrently executing
threads.

SEE ALSO
Device Event, and Interface Operations.
