Astronics OMNIBUS II NI PXIe, User Manual

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OMNIBUS II FEATURES
4-8 OmniBus II NI PXIe User Manual
tolerant device with high input impedance (10-µA leakage current). When used as
an output, you can verify the status of a core-discrete output by reading the input.
At power on all core-discrete outputs are tristated and are enabled by writing to the
output or by explicitly enabling it.
Ballard’s BTIDriver API provides functions to read, write, and enable (tristate)
the core discretes. The parameter dionum in the API functions
(
BTICard_ExtDIORd
,
BTICard_ExtDIOWr
,
BTICard_ExtDIOEnWr
,
etc.) specifies which discrete to read or write. Table 4.11 shows the mapping
between the external hardware pin and
dionum.
A specific sync or trigger can use one or more of the designated core discretes.
After a core discrete has been allocated as a trigger or sync using the enable and
mask parameters in a sync or trigger define API function, the line may no longer
be used as a discrete output or input. More than one core discrete, each with an
individually specified polarity, may be used in combination to define a sync or
trigger state. For instance, a trigger may be defined as a particular state of only one
input, or it may be defined as a particular combination of two or three trigger
inputs. Other triggers and syncs may use the same or different combinations of
these lines. Refer to the
BTIDriver software manuals for more information on
programming these discretes and their use as syncs and triggers.
Table 4.11 below shows the correlation between dionum , the output pin, and its
hardware reference designator. The last column shows which of these discretes
may be used as trigger inputs or sync outputs in the
BTIDriver API functions. The
names for core discretes are prefixed by
CDIO
(e.g.,
CDIO2
).
Pin
Name LFH
Pin
API
dionum
Trigger/Sync
Usage
CDIO0 11 1 Trigger A
CDIO1 21 2 Trigger B
CDIO2 51 3 Trigger C
CDIO3 41 4 -
CDIO4 13 5 Sync A
CDIO5 19 6 Sync B
CDIO6 49 7 Sync C
CDIO7 43 8 -
Table 4.11—Hardware Versus Software Designation of Core Discretes