Chapter 9
Counters
Counter n Source Signal
NI USB-621x User Manual
The selected edge of the Counter n Source signal increments and
decrements the counter value depending on the application the counter is
performing. Table 9-4 lists how this terminal is used in various
applications.
Table 9-4. Counter Applications and Counter n Source
Application
Pulse Generation
One Counter Time Measurements
Two Counter Time Measurements
Non-Buffered Edge Counting
Buffered Edge Counting
Two-Edge Separation
Routing a Signal to Counter n Source
Each counter has independent input selectors for the Counter n Source
signal. Any of the following signals can be routed to the Counter n Source
input.
•
80 MHz Timebase
•
20 MHz Timebase
•
100 kHz Timebase
•
PFI <0..3>, PFI <8..11>
In addition, Counter 1 TC or Counter 1 Gate can be routed to
Counter 0 Source. Counter 0 TC or Counter 0 Gate can be routed to
Counter 1 Source.
Some of these options may not be available in some driver software.
Routing Counter n Source to an Output Terminal
You can route Counter n Source out to any PFI <4..7> or PFII <12..15>
terminal.
Purpose of Source Terminal
Counter Timebase
Counter Timebase
Input Terminal
Input Terminal
Input Terminal
Counter Timebase
9-26
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