Chapter 6
Digital I/O
6-2
ni.com
Figure 6-1 shows the circuitry of one DIO line. Each DIO line is similar.
The following sections provide information about the various parts of the
DIO circuit.
Figure 6-1.
Non-Isolated S Series Digital I/O Circuitry
The DIO terminals are named P0.<0..7> on the device I/O connector.
The voltage input and output levels and the current drive levels of the DIO
lines are listed in the specifications of your device.
Static DIO for Non-Isolated Devices
(NI 6124 Only)
Each DIO line can be used as a static DI or DO line. You can
use static DIO lines to monitor or control digital signals. Each DIO can be
individually configured as a digital input (DI) or digital output (DO).
All samples of static DI lines and updates of DO lines are software-timed.
P0.6 and P0.7 on these devices also can control the up/down input of
general-purpose counters 0 and 1, respectively. However, it is
recommended that you use PFI signals to control the up/down input of the
counters. The up/down control signals, Counter 0 Up_Down and Counter 1
Up_Down, are input-only and do not affect the operation of the DIO lines.
DO
Sa
mple Clock
DO W
a
veform
Gener
a
tion FIFO
DO.
x
Direction Control
S
t
a
tic DI
DI
Sa
mple Clock
DI Ch
a
nge
Detection
I/O Protection
We
a
k P
u
ll-Down
P0.
x
S
t
a
tic DO
B
u
ffer
DI W
a
veform
Me
asu
rement
FIFO
