Chapter 4
Connecting Signals
4-34
ni.com
GPCTR1_GATE Signal
Any PFI pin can externally input the GPCTR1_GATE signal, which is
available as an output on the PFI4/GPCTR1_GATE pin.
As an input, GPCTR1_GATE is configured in edge-detection mode. You
can select any PFI pin as the source for GPCTR1_GATE and configure the
polarity selection for either rising or falling edge. You can use the gate
signal in a variety of different applications to perform such actions as
starting and stopping the counter, generating interrupts, saving the counter
contents, and so on.
As an output, GPCTR1_GATE monitors the actual gate signal connected to
general-purpose counter 1, even if the gate is being externally generated by
another PFI. This output is set to high-impedance at startup.
Figure 4-31 shows the timing requirements for the GPCTR1_GATE signal.
Figure 4-31.
GPCTR1_GATE Signal Timing
Rising-Edge
Polarity
Falling-Edge
Polarity
t
w
= 10 ns minimum
t
w