Chapter4 ConnectingSignals
©NationalInstruments Corporation 4-47 ATE Series User Manual
GPCTR1_SOURCE SignalAnyPFI pin can extern ally input the GPCTR1_SOURCE signal, which is
available as an output on the PFI3/GPCTR1_SOURCE pin.
As ani nput, the GPCTR1_SOURCE signal is configured in the
edge-detectionm ode. Youcan select any PFI pin as the source for
GPCTR1_SOURCE and configurethe polarity selection for either rising
or falling edge.
Asan output, the GPCTR1_SOURCE monitors the actual clock connected
to general-purpose counter 1, evenif the source clock is being externally
generated byan other PFI. This output is set to high-impedance at startup.
Figure 4-34 showsthe timing requirements for the GPCTR1_SOURCE
signal.
Figure4-34. GPCTR1_SOURCE Signal Timing
Themaximum allowed frequency is 20 MHz, with a minimum pulse width
of 10 ns high or low.There is no minimum frequency limitation.
The 20M Hz or100 kHz timebase normally generates the
GPCTR1_SOURCE unless you select some externalsource.
GPCTR1_GATE SignalAny PFIpin can ext ernally input the GPCTR1_GATE signal, which is
available as an output on the PFI4/GPCTR1_GATE pin.
As aninput, the GPCTR1_GATE signal is configured in edge-detection
mode. Youcan select any PFI pin as the source for GPCTR1_GATE and
configurethe polarity selection for either rising or falling edge. You can use
thegate signal in a variety of different applications to perform such actions
asstartin g and stopping the counter,generating interrupts, saving the
counter contents, and so on.
tw=23 ns minimum
tp=50 ns minimum
tw
tw
tp