JYTEK USB-62401, User Manual

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Operation 39
3.6.3 General Purpose Timer/Counter Modes
Ten programmable timer/counter modes are available. All initialize fol -
lowing a software-start signal set by the software. The GPTC software
reset initializes the status of the counter and reloads the initial
value to the counter. The operation remains halted until software start
is executed again. Operations under different modes are as follows.
Mode 1: Simple Gated-Event Counting
In this mode, the counter calculates the number of pulses on the
GPTC_CLK after a software start. Initial count can be loaded from the
software application. Current count value can be read back by soft -
ware any time with no influence on calculation. GPTC_GATE
enables/disables calculation. When GPTC_GATE is inactive, the
counter halts the current count value. Operation in which initial
count = 5, countdown mode is shown.
Figure 3-11: Mode 1-Simple Gated-Event Calculation
Mode 2: Single Period Measurement
The counter calculates the period of the signal on GPTC_GATE in
terms of GPTC_CLK. The initial count can be loaded from the soft -
ware application. After software start, the counter calculates 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 by the software application. Operation in which initial
count = 0, count-up mode is shown.
5 5 4 3 2 1 1 0 ffff
Gate
CLK
Count value
Software start