Chapter 7
Counters
X Series User Manual
7-8
ni.com
Sample Clocked Buffered Pulse-Width Measurement
A Sample Clocked B
u
ffered p
u
lse-width meas
u
rement is similar to single
p
u
lse-width meas
u
rement, b
u
t b
u
ffered p
u
lse-width meas
u
rement takes
meas
u
rements over m
u
ltiple p
u
lses correlated to a sample clock.
The co
u
nter co
u
nts the n
u
mber of edges on the So
u
rce inp
u
t while the Gate
inp
u
t remains active. On each sample clock edge, the co
u
nter stores the
co
u
nt in the FIFO of the last p
u
lse width to complete. A DMA controller
transfers the stored val
u
es to host memory.
Fig
u
re 7-7 shows an example of a sample clocked b
u
ffered p
u
lse-width
meas
u
rement.
Figure 7-7.
Sample Clocked Buffered Pulse-Width Measurement
Hardware-Timed Single Point Pulse-Width
Measurement
A hardware-timed single point (HWTSP) p
u
lse-width meas
u
rement has the
same behavior as a sample clocked b
u
ffered p
u
lse-width meas
u
rement.
Note
If a p
u
lse does not occ
u
r between sample clocks, an overr
u
n error will occ
u
r.
Note
(NI USB-634
x
/635
x
/636
x
Devices)
X Series USB devices do not s
u
pport
hardware-timed single point (HWTSP) operations.
For information abo
u
t connecting co
u
nter signals, refer to the
Default
Counter/Timer Pinouts
section.
G
a
te
S
o
u
rce
Sa
mple Clock
2
3
4
2
4
3
2
2
4
B
u
ffer
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