
Chapter 1
38
Figure 6: Example of Rate Generation Mode
Measure
Use measure mode to measure the interval between a selected start edge and a selected stop
edge of a signal connected to the external C/T input pin or external gate input pin of the
counter/timer. Refer to
for more information on edge types and how to use them to
measure frequency, period, and pulse width.
When you trigger the counter/timer in software, the counter increments from the time it
detects the selected start edge until it detects the stop edge. When it detects the selected stop
edge, the counter stops counting.
You can determine whether the measure mode operation is complete or not using software.
When the operation is complete, you can read the value of the counter.
Use the following equations to determine the frequency, period, and pulse width of the signal:
• Frequency = 18 MHz/Number of Counts
• Period = 1/Frequency
• Pulse width = Number of Counts/18 MHz
Note:
In measure mode, the internal C/T clock is used to calculate the interval of the signal
between the specified start and stop edges. The pulse width and period count are
automatically set to 0. You can specify the polarity of the output signal during and after the
measurement.
Pulse
Output
Signal
66% duty cycle
Rate Generation
Operation Starts
Internal C/T
Clock
Input Signal
High level
enables operation
Low level
disables operation
Rate Generation
Operation Stops
External
Gate Input
Signal
6.0 MHz frequency
18 MHz frequency
. . .
Summary of Contents for DT9840 Series
Page 1: ...DT9840 Series UM 19197 T User s Manual Title Page ...
Page 4: ......
Page 44: ...Chapter 1 44 ...
Page 76: ...Chapter 2 76 ...
Page 98: ...Appendix A 98 ...
Page 124: ...Appendix B 124 ...