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3.3.1 Software Trigger
The software trigger, generated by software command, is asserted immediately following
execution of specified function calls to begin the operation.
3.3.2 External Digital Trigger
An external digital trigger is generated when a TTL rising edge or falling edge is detected at the SMA
connector TRG IN on the front panel. As shown, trigger polarity can be selected by soft-ware. Note
that the signal level of the external digital trigger signal should be TTL compatible, and the minimum
pulse width 20 ns.
Pulse Width > 20ns
Pulse Width > 20ns
Rising Edge Trigger Event
Falling Edge Trigger Event
Figure 3-4: External Digital Trigger
3�3�3 PXI STAR Trigger
When PXI STAR is selected as the trigger source, the PXIe-69852 accepts a TTL-compatible digital
signal as a trigger signal.
Triggering occurs when a rising edge or falling edge is detected at PXI STAR, with trigger polarity
configurable by software. The minimum pulse width requirement of this digital trigger signal is 20 ns.
3.3.4 PXIe_DSTARB Trigger
The PXIe_DSTARB signal, a differential signal transmitted via the PXI Express Chassis backplane,
distributes high-speed, highquality trigger signals. When PXIe_DSTARB is selected as the trigger
source, the PXIe-69852 accepts a fast-switching LVDS digital signal as a trigger signal. Triggering occurs
when a rising edge or falling edge is detected at PXIe_DSTARB, with trigger polarity configurable by
software, with minimum pulse width requirement of 20 ns.