©
National Instruments Corporation
7-1
7
PFI
USB-621
x
devices have m
u
ltiple Programmable F
u
nction Interface (PFI)
signals.
Each inp
u
t PFI can be individ
u
ally config
u
red as the following:
•
A static digital inp
u
t
•
A timing inp
u
t signal for AI, AO, or co
u
nter/timer f
u
nctions
Each o
u
tp
u
t PFI can be individ
u
ally config
u
red as the following:
•
A static digital o
u
tp
u
t
•
A timing o
u
tp
u
t signal from AI, AO, or co
u
nter/timer f
u
nctions
Note
(USB-6212/6216 Devices)
PFI signals on USB-6212/6216 devices can be config
u
red
as inp
u
t or o
u
tp
u
t.
Each PFI inp
u
t also has a programmable debo
u
ncing filter. Fig
u
shows the circ
u
itry of an inp
u
t PFI line.
Figure 7-1.
USB-621
x
PFI Input Circuitry
S
t
a
tic DI
I/O Protection
To Inp
u
t Timing
S
ign
a
l
S
elector
s
PFI
Filter
s
We
a
k P
u
ll-Down
PFI/DIO Pin
I
s
ol
a
tion
B
a
rrier
(U
S
B-6215/
6216/6218
device
s
only)
Digit
a
l
I
s
ol
a
tor
s
