ADLINK DAQe-2006 - Manual (Page 71)

Operation Theory 59
Mode 2: Single Period Measurement
In this mode, the counter counts the period 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 between
two active edges of GPTC_GATE. After the completion of the
period interval on GPTC_GATE, GPTC_OUT outputs high and
then current count value can be read-back by software.
Figure 4-24 illustrates the operation where initial count = 0,
count-up mode.
Figure 4-24: Mode 2 Operation
Mode 3: 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.