Chapter 2
Hardware Overview of the NI 78xxR
R Series Multifunction RIO User Manual
2-22
ni.com
wide. All of these lines connect to the FPGA on the NI PXI-781
x
R/783
x
R.
The PXI local b
u
s right lines on the NI PXI-781
x
R/783
x
R are
PXI/PXI_Lbr<0..12>. The PXI local b
u
s left lines on the
NI PXI-781
x
R/783
x
R are PXI/PXI_Lbl<0..12>.
The NI PXI-781
x
R/783
x
R can config
u
re each PXI local b
u
s line either as
an inp
u
t or an o
u
tp
u
t signal. Only one device can drive the same physical
local b
u
s line at a time. For example, if the NI PXI-781
x
R/783
x
R is
config
u
red to drive a signal on PXI/PXI_Lbr 0, the device in the slot
immediately to the right m
u
st have its PXI/PXI_Lbl 0 line config
u
red as an
inp
u
t.
Caution
Do
not
drive the same PXI local b
u
s line with the NI PXI-781
x
R/783
x
R and
another device sim
u
ltaneo
u
sly. S
u
ch signal driving can damage both devices. NI is
not
liable for any damage res
u
lting from s
u
ch signal driving.
The NI PXI-781
x
R/783
x
R local b
u
s lines are only compatible with 3.3 V
signaling LVTTL and LVCMOS levels.
Caution
Do
not
enable the local b
u
s lines on an adjacent device if the device drives
anything other than 0–3.3V LVTTL signal levels on the NI PXI-781
x
R/783
x
R. Enabling
the lines in this way can damage the NI PXI-781
x
R/783
x
R. NI is
not
liable for any damage
res
u
lting from enabling s
u
ch lines.
The left local b
u
s lines from the left peripheral slot of a PXI backplane
(Slot 2) are ro
u
ted to the star trigger lines of
u
p to 13 other peripheral slots
in a two-segment PXI system. This config
u
ration provides a dedicated,
delay-matched trigger signal between the first peripheral slot and the
other peripheral slots for precise trigger timing signals. For example—as
shown in Fig
u
re 2-12—an NI PXI-781
x
R/783
x
R in Slot 2 can send an
independent trigger signal to each device pl
u
gged into Slots <3..15>
u
sing
the PXI/PXI_Lbl<0..12>. Each device receives its trigger signal on its own
dedicated star trigger line.
Caution
Do
not
config
u
re the NI 781
x
R/783
x
R and another device to drive the same
physical star trigger line sim
u
ltaneo
u
sly. S
u
ch signal driving can damage the
NI 781
x
R/783
x
R and the other device. NI is
not
liable for any damage res
u
lting from
s
u
ch signal driving.
Summary of Contents for PXI-7842
Page 1: ...PXI 7842...
