Pulse-Width Measurement
In pulse-width measurements, the counter measures the width of a pulse on its Gate input signal. You can configure the counter to measure the width of high pulses or low pulses on the Gate signal.
You can route an internal or external periodic clock signal (with a known period) to the Source input of the counter. The counter counts the number of rising (or falling) edges on the Source signal while the pulse on the Gate signal is active.
You can calculate the pulse width by multiplying the period of the Source signal by the number of edges returned by the counter.
A pulse-width measurement will be accurate even if the counter is armed while a pulse train is in progress. If a counter is armed while the pulse is in the active state, it will wait for the next transition to the active state to begin the measurement.
Single Pulse-Width Measurement
With single pulse-width measurement, the counter counts the number of edges on the Source input while the Gate input remains active. When the Gate input goes inactive, the counter stores the count in a hardware save register and ignores other edges on the Gate and Source inputs. Software then reads the stored count.
Figure 9-6shows an example of a single pulse-width measurement.
GATE | | | |
SOURCE | | | |
Counter Value | 0 | 1 | 2 |
HW Save Register | | | 2 |
Figure 9-6.Single Pulse-Width Measurement
Buffered Pulse-Width Measurement
Buffered pulse-width measurement is similar to single pulse-width measurement, but buffered pulse-width measurement takes measurements over multiple pulses.