Konica Minolta PCI-1712L user manual q Event counting

Chapter 5

Counter/timer operation modes

We enhance the gate function for more applications. For example, event counting, rate generation, one shot, frequency measurement and pulse width measurement. We make some innovative arrangements of clock and gate of counter. For detailed information, please refer to Appendix D.12 to D.14 and Intel® 82C54 User’s Manual. The following sections show how to implement counter functions.

qEvent counting

The event counting function helps user count events from the counter’s associated clock input source.

Each counter features 16-bit, and therefore you can count a maximum of 65,535 events before the counter overflows and returns to 0. If you need wider range for event counting, you can use a cascaded 32-bit counter for counting up to 4,294,967,296 events.

Please follow the procedure below when using software:

1.Select a counter ( e.g. counter 0) to do event counting.

2.Set the counter in mode 0 (Please refer to Intel® 82C54 User’s Manual).

3.Connect the pin CNT0_CLK of the counter to the event signal source.

4.Set the gate type of the counter to positive (logic-high).

5.Reset the counter to 65,535.

6.Pull high the gate input, and then start down counting.

7.After event counting is finished, read the value from the counter.

8.Calculate the number of events.

For example, if the reset value of counter is 65,535 and the read back value is 43930, then the number of events is 65535 minus 43930 and thus equals 21605.

qRate generation

The rate generation function helps user generate a continuous pulse output signal from the counter. User can use it as an external clock to output signal to pace other operations, such as analog input, analog output, or other counter/timer operations.

The frequency of input clock and the number of the counter determine the period of the output pulse. If you are using one counter (not cascaded), you can output pulses with a maximum frequency of 5MHz. In rate generation mode, either the internal or external clock source is

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