Chapter4 ConnectingSignals
©NationalInstruments Corporation 4-25 NI6013/6014 User Manual
STARTSCANSignal
Any PFIpin can receive as an input the STARTSCAN signal, which is
availableas an output on the PFI7/STARTSCAN pin. Refer to Figures 4-11
and 4-12 for the relationship of STARTSCAN to the DAQ sequence.
As ani nput, STARTSCANis configured in the edge-detection mode.
Youcan select any PFI pin as the source for STARTSCANand configure
thepolarity selection for either rising or falling edge. The selected edge of
STARTSCANinitiates a scan. The sample interval counter starts if you
select internally triggered CONVERT*.
As ano utput, STARTSCANreflects the actual start pulse that initiates a
scan,even if the starts are being externally triggered by another PFI. You
havetwo output options. The first is an active high pulse with a pulse width
of5 0t o 100 ns, which indicates the start of the scan. The second action is
anactive high pulse that terminates at the start of the last conversion in the
scan,which indicates a scan in progress. STARTSCAN is deasserted toff
afterthe last conversion inthe scan is initiated. This output is set to
high-impedance at startup.
Figures 4-17 and 4-18 showthe input and outp ut timing requirements for
the STARTSCANsignal.
Figure4-17. STARTSCAN Input Signal Timing
Rising-Edge
Polarity
Falling-Edge
Polarity
tw=10 ns minimum
tw