Chapter 4
Connecting the Signals
©
National Instruments Corporation
4-35
EXTSTROBE* Signal
EXTSTROBE* is an output-only signal that generates either a single pulse
or a sequence of eight pulses in the hardware-strobe mode. An external
device can use this signal to latch signals or to trigger events. In the
single-pulse mode, the application software controls the level of
EXTSTROBE*. A 10
µ
s and a 1.2
µ
s clock are available for generating
a sequence of eight pulses in the hardware-strobe mode. Figure 4-27
shows the timing for the hardware-strobe mode EXTSTROBE* signal.
Note
You cannot control EXTSTROBE using NI-DAQ.
Figure 4-27.
EXTSTROBE* Signal Timing
Waveform Generation Timing Connections
The analog group defined for the device is controlled by WFTRIG,
UPDATE*, and UISOURCE.
WFTRIG Signal
Any PFI pin can externally input the WFTRIG signal, which is available as
an output on the PFI6/WFTRIG pin.
As an input, WFTRIG is configured in the edge-detection mode. You can
select any PFI pin as the source for WFTRIG and configure the polarity
selection for either rising or falling edge. The selected edge of WFTRIG
starts the waveform generation for the DACs. If you select internally
generated UPDATE*, the update interval (UI) counter starts.
As an output, WFTRIG reflects the trigger that initiates waveform
generation, even if the waveform generation is externally triggered by
another PFI. The output is an active high pulse with a pulse width of
50 to 100 ns. This output is set to high-impedance at startup.
V
OH
V
OL
t
w
t
w
t
w
= 600 ns or 5
s
