The timer can operate from an external aperiodic clock by setting CSYNC =
0. Refer to Synchronous vs. Asynchronous Operation for more
information about clock synchronization. Note that with CSYNC =
1, clock synchronization delays will apply, which
is unreliable since the input signal is aperiodic and may not be toggling.
With CSYNC = 0, the effect of the gate is immediate,
without synchronization delays. For reliable operation the user must ensure
that the inputs meet reasonable setup and hold times of a few nanoseconds.
The following use case demonstrates this.