ADLINK PXI-2022 - Manual (Page 53)

Function Block and Operation Theory 45
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 com-pletion of the
period interval on GPTC_GATE, GPTC_OUT outputs high and
then current count value can be read-back by software. Figure
4-17 il-lustrates the operation where initial count = 0, count-up
mode.
Figure 4-17: 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
and then current count value can be read-back by software.
Figure 4-18 illustrates the operation where initial count = 0,
count-up mode.
Figure 4-18: Mode 3 Operation
0 0 1 2 3 4 5 5 5
Gate
CLK
Count value
Software start
0 0 1 2 3 4 5 5 5
Gate
CLK
Count value
Software start