Chapter4 SignalConnections
©NationalInstruments Corporation 4-33 6023E/6024E/6025EUser Manual
Figure4-18. TypicalPretriggered Acquisition
SCANCLK Signal
SCANCLKis an output-only signal that generates a pulse with theleading
edgeoccurring approximately 50 to 100 nsafteran A/D conversion begins.
The polarity of this output is software-selectable, but is typically
configured so that a low-to-high leading edge can clock external analog
input multiplexers indicating when the input signal has been sampled and
can be removed. This signal has a 400 to 500 ns pulse width and is
software-enabled.Figure 4-19shows the timing for the SCANCLK signal.
Figure4-19. SCANCLKSignal Timing
EXTSTROBE* Signal
EXTSTROBE*is an output-only signal that generates either a single pulse
ora s equence ofei ghtp ulsesi n the hardware-strobe mode. Ane xternal
device can use this signal to latch signals or to trigger events. In the
single-pulse mode, software controls the level of the EXTSTROBE*
signal. A 10 µsanda1.2µsclo ckare availab le forg enerating a sequence
ofeight pulses in the hardware-strobe mode. Figure 4-20shows the timing
for the hardware-strobe mode EXTSTROBE* signal.
Don'tCare
01231 0222
TRIG1
TRIG2
STARTSCAN
CONVERT*
ScanCounter
tw
tw=400 to 500 ns
td=50to100ns
td
CONVERT*
SCANCLK