National Instruments NI 6120 用户手册

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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, software controls the level of EXTSTROBE*. A 10

µs 

and a 1.2

µs clock are available for generating a sequence of eight pulses in 

the hardware-strobe mode.

EXTSTROBE* cannot be enabled through NI-DAQ.

Figure 4-24 shows the timing for the hardware-strobe mode 
EXTSTROBE* signal.

 

Figure 4-24.  EXTSTROBE* Signal Timing

The AO group defined for the NI 6115/6120 is controlled by WFTRIG, 
UPDATE*, and UISOURCE.

Any PFI pin can receive as an 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 UI counter starts.

As an output, WFTRIG reflects the trigger that initiates waveform 
generation, even if another PFI is externally triggering the waveform 
generation. The output is an active high pulse with a pulse width of 
25 to 50 ns. This output is set to high-impedance at startup.

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