Chapter 5
Analog Output
5-8
ni.com
Using an External Source
Use any inp
u
t PFI line as the so
u
rce of AO Sample Clock.
Routing AO Sample Clock to an Output Terminal
Yo
u
can ro
u
te AO Sample Clock (as an active low signal) o
u
t to any o
u
tp
u
t
PFI terminal.
Other Timing Requirements
A co
u
nter on yo
u
r device internally generates AO Sample Clock
u
nless yo
u
select an external so
u
rce. AO Start Trigger starts the co
u
nter and either the
software or hardware can stop it once a finite generation completes. When
u
sing an internally generated AO Sample Clock, yo
u
also can specify a
config
u
rable delay from AO Start Trigger to the first AO Sample Clock
p
u
lse. By defa
u
lt, this delay is two ticks of AO Sample Clock Timebase.
Fig
u
re 5-6 shows the relationship of AO Sample Clock to AO Start Trigger.
Figure 5-6.
AO Sample Clock and AO Start Trigger
AO Sample Clock Timebase Signal
The AO Sample Clock Timebase (ao/SampleClockTimebase) signal is
divided down to provide a so
u
rce for AO Sample Clock.
Yo
u
can ro
u
te any of the following signals to be the AO Sample Clock
Timebase signal:
•
20 MHz Timebase
•
100 kHz Timebase
•
(USB-6211/6215 Devices)
PFI <0..3>
AO
Sa
mple Clock Time
bas
e
AO
S
t
a
rt Trigger
AO
Sa
mple Clock
Del
a
y
From
S
t
a
rt
Trigger
