Chapter 4
Connecting the Signals
©
National Instruments Corporation
4-27
Figure 4-16.
Typical Pretriggered Sequence
TRIG1 Signal
Any PFI pin can externally input the TRIG1 signal, which is available as
an output on the PFI0/TRIG1 pin.
As an input, TRIG1 is configured in the edge-detection mode. You can
select any PFI pin as the source for TRIG1 and configure the polarity
selection for either rising or falling edge. The selected edge of TRIG1 starts
the sequence for both posttriggered and pretriggered acquisitions. Refer to
Figures 4-15 and 4-16 for the relationship of TRIG1 to the sequence. Refer
to Chapter 3,
, for more information on analog
triggering.
As an output, TRIG1 reflects the action that initiates a sequence, even if the
acquisition is externally triggered by another PFI. The output is an active
high pulse with a pulse width of 50 to 100 ns. This output is set to
high-impedance at startup.
n/a
0
1
2
3
1
0
2
2
2
TRIG1
TRIG2
STARTSCAN
CONVERT*
Scan Counter
