10

PFI

NI 621x devices have up to eight input and eight output Programmable Function Interface (PFI) signals, which also can be used as static digital input or static digital output signals.

Each input PFI can be individually configured as the following:

•A static digital input

•A timing input signal for AI, AO, or counter/timer functions

Each output PFI can be individually configured as the following:

•A static digital output

•A timing output signal from AI, AO, or counter/timer functions

Each PFI input also has a programmable debouncing filter. Figure 10-1shows the circuitry of an input PFI line.

 

 

 

 

 

 

 

 

 

 

 

 

 

Isolation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Barrier

 

 

 

 

 

 

 

 

 

 

 

Static DI

(USB-6215

 

PFI <0..3>/P0,

 

 

 

 

 

 

 

 

 

 

 

 

and USB-6218

 

 

I/O Protection

 

 

 

 

 

 

 

 

 

 

devices only)

 

PFI <8..11>/P0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Weak Pull-Down

 

 

 

 

 

 

 

 

Digital

To Input Timing

 

 

 

 

PFI

 

 

 

 

Isolators

Signal Selectors

 

 

 

 

 

 

 

Filters

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 10-1.NI 621x PFI Input Circuitry

Figure 10-2shows the circuitry of an output PFI line.

© National Instruments Corporation

10-1

NI USB-621x User Manual