National Instruments NI VISION PCI-8254R 用户手册
Chapter 2
Hardware Overview
© National Instruments Corporation
2-7
Pulse Width
Pulse width is the amount of time between the first (assertion) edge of a
pulse and the second (deassertion) edge. Pulse width is configurable only
in microseconds from 1 µs to 4,294,967,295 µs.
pulse and the second (deassertion) edge. Pulse width is configurable only
in microseconds from 1 µs to 4,294,967,295 µs.
Trigger Polarity
Each pulse generator can be individually configured for rising or falling
edge triggering. Even if multiple pulse generators are using the same
trigger, each can have different polarities.
edge triggering. Even if multiple pulse generators are using the same
trigger, each can have different polarities.
Figure 2-2 shows the output of a pulse generator configured to look for a
rising edge trigger and output a high pulse with a microsecond width and
delay.
rising edge trigger and output a high pulse with a microsecond width and
delay.
Figure 2-2. Output pulse generator
Figure 2-3 shows how to create a high and low pulse train with a
microsecond delay and width.
microsecond delay and width.
Figure 2-3. High and low pulse train
Trigger
Pulse
Delay
Width
Low Pulse Train
High Pulse Train
Delay
Width
Width
Delay
Software
Start