Routing Ao Start Trigger To An Output Terminal; Ao Pause Trigger Signal - National Instruments USB-621 Series User Manual

Chapter 5 Analog Output

AO Pause Trigger Signal

NI USB-621x User Manual
•
(USB-6218 Devices)
• AI Start Trigger (ai/StartTrigger)
The source also can be one of several internal signals on your USB-621x
device. Refer to Device Routing in MAX in the NI-DAQmx Help or the
LabVIEW Help in version 8.0 or later for more information.
You also can specify whether the waveform generation begins on the rising
edge or falling edge of AO Start Trigger.

Routing AO Start Trigger to an Output Terminal

You can route AO Start Trigger out to any output PFI terminal. The output
is an active high pulse.
Use the AO Pause Trigger signal (ao/PauseTrigger) to pause the generation
of AO samples in a DAQ sequence. That is, when AO Pause Trigger is
active, no samples occur.
If the AO Sample Clock is derived from AO Sample Clock Timebase—for
example, when you choose the onboard 20 MHz or 100 kHz
Timebase—the AO Sample Clock Timebase is divided down by a
programmable clock divider circuit and then drives AO Sample Clock,
as shown in Figure 5-3.
In this case, AO Pause Trigger masks off AO Sample Clock Timebase
pulses from the programmable clock divider.
For example, an internal timebase is routed to AO Sample Clock Timebase
and the Timebase divisor is 5, as shown in Figure 5-4. AO Sample Clock
normally asserts once for every five periods of AO Sample Clock
Timebase; the programmable clock divider counts down from 4 to 0. When
AO Pause Trigger is asserted, the programmable clock divider ignores
pulses of AO Sample Clock Timebase.
PFI <0..3>, PFI <8..11>
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