Keithley DAS-8 Series User Manual page 42

Clock pulse
Software forces
Software writes initial
output low
count value of 3
Output
Figure 2-6. Pulse on Terminal Count Mode
• Programmable one-shot (Mode 1) — This mode is useful for
providing a hardware-triggered delay or one-shot pulse. The output is
initially high. A trigger loads the initial count value into the counter.
At the next clock pulse after the trigger, the output goes low and
remains low until the counter reaches zero. (The one-shot pulse is n
clock cycles in duration, where n indicates the loaded count.) After
the counter reaches zero, the output goes high and remains high until
the clock pulse after the next trigger; this makes the one-shot pulse
retriggerable.
You do not have to reload the count into the counter. The gate input
has no effect on the output. Writing a new count to the counter during
a one-shot pulse does not affect the current one-shot pulse.
Figure 2-7 illustrates programmable one-shot mode.
Clock pulse
Trigger loads initial count
value of 3
Output
3
Figure 2-7. Programmable One-Shot Mode
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3 2 1
2 1
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