National Instruments PCI-6601, User Manual

Page: 35 / 52

Chapter 3 Signal Connections
NI 660x User Manual 3-10 ni.com
Fig
u
re 3-4 shows the timing req
u
irements for the Ctr n So
u
rce signal.
Figure 3-4. Timing Requirements for Ctr n Source Signal
Fig
u
re 3-4 shows the minim
u
m p
u
lse width and period that yo
u
m
u
st
u
se
for the Ctr
n
So
u
rce signal. This signal m
u
st satisfy both minim
u
m criteria.
If the high phase of the Ctr
n
So
u
rce signal is Tsrcpw ns, the low phase m
u
st
be Tsrcper - Tsrcpw.
Table 3-4. Minimum Pulse Width and Period for Ctr n Source Internal Signals
Parameter
Minimum
Minimum with
RTSI Connector Description NI 6601 NI 6602
Tsrcpw (witho
u
t
prescaling)
5 ns 5 ns 5 ns Ctr n So
u
rce minim
u
m p
u
lse
width (witho
u
t prescaling)
Tsrcpw (with
prescaling) 3.5 ns 3.5 ns 3.5 ns Ctr n So
u
rce minim
u
m p
u
lse
width (with prescaling)
Tsrcper (witho
u
t
prescaling)
50 ns 12.5 ns 50 ns Ctr
n
So
u
rce minim
u
m period
(witho
u
t prescaling)
Tsrcper (with
prescaling) 16.67 ns 8 ns 16.67 ns Ctr n So
u
rce minim
u
m period
(with prescaling)
Ctr
n
Source
Tsrcpw
Tgatepw
Tsrcper