Chapter 3
Hardware Overview
3-6
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Programmable Function Inputs
The 10 PFI pins are connected to the signal routing multiplexer for each
timing signal, and software can select any PFI pin as the external source for
a given timing signal. It is important to note that any of the PFI pins can be
used as an input by any of the timing signals and that multiple timing
signals can simultaneously use the same PFI. This flexible routing scheme
reduces the need to change physical connections to the I/O connector for
different applications.
To use the PFI pins as outputs, you must use the Route Signal VI or the
Select Signal VI to individually enable each of the PFI pins to output a
specific internal timing signal. For example, if you need the UPDATE*
signal as an output on the I/O connector, software must turn on the output
driver for the PFI5/UPDATE* pin.
