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Frequency Counter Module

Frequency counter module has two frequency counters. Either of them can measure frequency of a digital signal on A.3 or A.4 pin. Frequency is measured by counting the number of pulses on the corresponing I/O pin per second. Minimum high time (T1) and low time (T0) of a pulse should be 83 ns.

While T1 and T0 are greater than 83 ns, GPIO-24 adapter frequency counter can measure frequency up to 5 MHz.

Any time you can retrieve current frequency with GPIO_GET_FR_CNT_VAL command.

Besides sending measurement results on demand, a frequency counter can generate an event to notify the user when user-defined measurement limits are reached. You can also configure the frequency counter to send events periodically with a predefined repeat interval. For more detailed information see Section 10.1, “Frequency Counter Event”.

The GPIO_SET_FR_CNT_CFG command is used to configure either of the frequency counters. To retrieve the configuration settings, send GPIO_GET_FR_CNT_CFG command.