User's Manual

Chapter 4 Signal Connections
AT-MIO/AI E Series User Manual 4-32  National Instruments Corporation
detection requirements for each timing signal are listed within the
section that discusses that individual signal.
In edge-detection mode, the minimum pulse width required is 10 ns.
This applies for both rising-edge and falling-edge polarity settings.
There is no maximum pulse-width requirement in edge-detect mode.
In level-detection mode, there are no minimum or maximum
pulse-width requirements imposed by the PFIs themselves, but there
may be limits imposed by the particular timing signal being controlled.
These requirements are listed later in this chapter.
Data Acquisition Timing Connections
The data acquisition timing signals are SCANCLK, EXTSTROBE*,
TRIG1, TRIG2, STARTSCAN, CONVERT*, AIGATE, and
SISOURCE.
Posttriggered data acquisition allows you to view only data that is
acquired after a trigger event is received. A typical posttriggered data
acquisition sequence is shown in Figure 4-13. Pretriggered data
acquisition allows you to view data that is acquired before the trigger of
interest in addition to data acquired after the trigger. Figure 4-14
shows a typical pretriggered data acquisition sequence. The description
for each signal shown in these figures is included later in this chapter.
Figure 4-13. Typical Posttriggered Acquisition
13042
TRIG1
STARTSCAN
CONVERT*
Scan Counter