Philippe Gerum wrote:
Just one question: what's the reason why the periodic mode
is disabled by default ?
Because AFAICT, most people would rather use the aperiodic timing mode
in usual configurations for a much better accuracy. Since the periodic
mode uses the available hw PIT and programs it once (or even some
decrementer but without handling the time drift when reprogramming it
after each shot), it suffers from cumulated rounding errors of the
period. If you look at the jitter results of a trivial periodic loop
over a broad timescale, you will see the wakeup time irremediably drift,
whilst the average interval between shots remains stable and reasonably
accurate. The periodic timer should be used for configurations that only
need to enforce delays or timeouts, and not, well, precise timings.
If it's for accuracy, keep it that way!
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