Chapter 8
PFI
©
National Instruments
8-5
X Series User Manual
Figure 8-2.
PFI Input Signal Connections
PFI Filters
Yo
u
can enable a programmable debo
u
ncing filter on each PFI, RTSI,
PXI_STAR, or PXIe-DSTAR<A,B> signal. When the filters are enabled,
yo
u
r device samples the inp
u
t on each rising edge of a filter clock. X Series
devices
u
se an onboard oscillator to generate the filter clock.
The following is an example of low to high transitions of the inp
u
t signal.
High-to-low transitions work similarly.
Ass
u
me that an inp
u
t terminal has been low for a long time. The inp
u
t
terminal then changes from low to high, b
u
t glitches several times. When
the filter clock has sampled the signal high on N consec
u
tive edges, the low
to high transition is propagated to the rest of the circ
u
it. The val
u
e of N
depends on the filter setting; refer to Table 8-1.
PFI 0
S
o
u
rce
PFI 2
S
o
u
rce
X
S
erie
s
Device
D GND
PFI 2
PFI 0
I/O Connector
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com