Hi all
I need to have a function with some control code in it to execute at regular
and consistent intervals.
The way I've done this is just to create a thread and trap the execution path
in an infinite loop using while(1){some code;cyg_thread_delay()} or
for(;;){some code; cyg_thread_delay()}.
The trouble with this approach is that if the code doesn't take the same path
every time, then the overall interval will vary and the drift will be
cumulative. This hasn't mattered too much until now, but I need it to not drift
for my current application. I guess it could be improved by using
cyg_real_time_clock() at the start and end of the code section to find how long
it took then modify the delay time to try to keep the time interval at which
the code is started the same, but it seems a bit clumsy and might suffer from
jitter which would still be cumulative.
The other way I've tried is to use a timer/alarm attached to the system clock,
but this executes in a DSR context which causes some limitations and I would
prefer to use a normal thread context.
Could I use a cyg_thread_suspend() at the end of each iteration then re-wake
the thread from an alarm handler?
Is there anything which I've missed like a scheduler policy or API call which
might help?
Do I need to resort to a hardware timer to achieve this goal?
Thanks for any thoughts/insight,
Steven
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