Chapter4 HardwareOverview
NI5102 User Manual 4-20 ni.com
PFI Lines
All NI 5102 digitizers have two multipurpose programmable function
digital input/output lines, PFI1 and PFI2, that you can use for external
timing and triggering or outputting various signals. You can individually
select the direction of these lines to be input or output.

PFI Lines as Inputs

PFI1 orPFI2 can b e selected as inputs for the Start Trigger, Stop Trigger,
andScan Clock signals. On the NI 5102 (PXI), PFI2 is accessible through
the optional 9-pinmini-DIN to BNC female cable adapter. Unless your
application requires the PFI2 signal to be passed through to the PXI
backplane on TRIG0 (SCANCLK), disable the backplane scan clock via
your application software (reset state is disabled).

PFI Lines as Outputs

On the NI 5102 (PXI), PFI2 is accessible through the optional 9-pin
mini-DINto BNC female cable adapter. PFI1 or PFI2 can be selected to
output the following digital signals:
•StartTrigger—This signal is synchronized to the 20 MHz timebase.
When the Startcondition is satisfied,either through a software,
analog, or digital trigger,Start Trigger will transition high for 100 ns
(twoclo ckp eriods of the 20 MHz timebase) and transition back
to its idle state.
•Stop Trigger—Thissignal is s ynchronized to the 20 MHz timebase.
Whenthe Stop condition is satisfied, either through an analog or digital
trigger,Stop Trigger will transition high for 100 ns(two clock periods
ofthe 20 MHz timebase)and transition back to its idle state.
•Scan Clock—This signal is also the clock to the ADC that represents
the rate at which the input is sampled. The default state of this signal
is high.
•End of Acquisition—This signal is generated internally to indicate to
internalstate machines that acquisition has ended. End of Acquisition,
synchronousto Scan Clock, pulses high for two Scan Clockperiods at
the end of acquisition. This signal may be useful to trigger external
circuits for timing critical applications.