ADLINK PXI-2208 - Manual (Page 79)

Operation Theory 67
Figure 4-24: Mode2 Operation
Mode3: Single Pulse-width Measurement
In this mode, the counter counts the pulse-width of the signal
on GPTC_GATE in terms of GPTC_CLK. Initial count can be
loaded from software. After the software-start, the counter
counts the number of active edges on GPTC_CLK when
GPTC_GATE is in its active state. After the completion of the
pulse-width interval on GPTC_GATE, GPTC_OUT outputs
high, then current count value can be read-back by software.
Figure 4-25 illustrates the operation where initial count = 0,
count-up mode.
Figure 4-25: Mode3 Operation