In SX Microcontrollers, SX/B Compiler and SX-Key Tool, peterverkaik wrote:

From a user point of view, it might be better to specify a task interval time as a rate,
just as with interrupt. The compiler can calculate the interval time ticks. Also, the
initial taskDelay can be set to 1 for all tasks, meaning 1st task runs at 1, 2nd task runs at 2, etc.
After a task has run, it will be rescheduled using its interval tick.
So we can use

myTask TASK rate

where rate equals the number of times per second the task must run.
The totalTaskRate equals the sum of the 8 tasks with the highest rates.

From this TASKTICK can be calculated.
Example:
interrupt rate is 100_000 (isr cycle time is 10usec)
8 tasks all with rate 50, then totalTaskRate is 400
TASKTICK = isrRate/totalTaskRate = 100_000/400 = 250
TASKTICK should calculate into range 1 to 256, if not, the user must specify another interrupt rate
or other task rates.

Bean, you suggested that TASKTICK should be runtime configurable. I don't think that is
wise, because TASKTICK is global to all tasks. Better to change a task's interval tick to
adjust the task rate.
With the given test program, a task can easily change its own interval tick. When a task runs,
and it alters its interval tick, it will be rescheduled with this new tick upon return.
The only problem with changing interval ticks (eg. taskrate), is that TASKTICK also should be
 recalculated then, and because of that, also the interval ticks of all tasks. However, if a task
changes its interval tick for a short time, and then restores the original value, it may
not give problems at all.

regards peter

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