Chapter4 ConnectingSignals
NI6013/6014 User Man ual 4-34 ni.com
Themaximum allowed frequency is 20 MH z, with a minimum pulse width
of 23 ns high or low.There is no minimum frequency limitation.
Either the 20 MHz or 100 kHz internal timebase normally generates
UISOURCEunless you select someexternal source.
General-Purpose Timing Signal Connections
The general-purpose timing signals are GPCTR0_SOURCE,
GPCTR0_GATE, GPCTR0_OUT, GPCTR0_UP_DOWN,
GPCTR1_SOURCE, GPCTR1_GATE, GPCTR1_OUT,
GPCTR1_UP_DOWN, and FREQ_OUT.
GPCTR0_SOURCE Signal
AnyPFI pin can extern ally input the GPCTR0_SOURCE signal, which is
available as an output on the PFI8/GPCTR0_SOURCE pin.
Asan input, GPCTR0_SOURCE is configured in the edge-detection mode.
Youcan select any PFI pin as the source for GPCTR0_SOURCE and
configurethe polarity selection for either ri sing orfalling edg e.
As anoutput, GPCTR0_SOURCE reflects the actual clock connected to
general-purposecounter 0,even if another PFI externally inputs the source
clock. This output is set to high-impedance at startup.
Figure 4-29 showsthe timing requirements for GPCTR0_ SOURCE.
Figure4-29. GPCTR0_SOURCE Signal Timing
Themaximum allowed frequency is 20 MHz, with a minimum pulse width
of 23 ns high or low.There is no minimum frequency limitation.
The20 MHz or 100 kHz timebase normally generates GPCTR0_SOURCE
unlessyou select some external source.
t
w
=23 ns minimum
t
p
=50 ns minimum
t
w
t
w
t
p