Chapter 8
Counters
8-20
ni.com
Single Two-Signal Edge-Separation Measurement
With single two-signal edge-separation meas
u
rement, the co
u
nter co
u
nts
the n
u
mber of rising (or falling) edges on the So
u
rce inp
u
t occ
u
rring
between an active edge of the Gate signal and an active edge of the A
u
x
signal. The co
u
nter then stores the co
u
nt in a hardware save register and
ignores other edges on its inp
u
ts. Software then reads the stored co
u
nt.
Fig
u
re 8-20 shows an example of a single two-signal edge-separation
meas
u
rement.
Figure 8-20.
Single Two-Signal Edge-Separation Measurement
Buffered Two-Signal Edge-Separation Measurement
B
u
ffered and single two-signal edge-separation meas
u
rements are similar,
b
u
t b
u
ffered meas
u
rement meas
u
res m
u
ltiple intervals.
The co
u
nter co
u
nts the n
u
mber of rising (or falling) edges on the So
u
rce
inp
u
t occ
u
rring between an active edge of the Gate signal and an active
edge of the A
u
x signal. The co
u
nter then stores the co
u
nt in a hardware save
register. On the next active edge of the Gate signal, the co
u
nter begins
another meas
u
rement. A USB Signal Stream transfers the stored val
u
es to
host memory.
AUX
Co
u
nter
Armed
8
0 0 0 0 1 2
3
4 5 6 7 8 8 8
Me
asu
red Interv
a
l
GATE
S
OURCE
Co
u
nter V
a
l
u
e
HW
Sa
ve Regi
s
ter
