book: add some notes about the timer queue

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Jorge Aparicio 2018-12-16 21:24:10 +01:00
parent d98f6c9a61
commit 5b032243e6

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@ -1,8 +1,16 @@
# Timer queue # Timer queue
When the `timer-queue` feature is enabled the RTFM framework includes a *global When the `timer-queue` feature is enabled the RTFM framework includes a *global
timer queue* that applications can use to *schedule* software tasks to run some timer queue* that applications can use to *schedule* software tasks to run at
time in the future. some time in the future.
> **NOTE**: The timer-queue feature can't be enabled when the target is
> `thumbv6m-none-eabi` because there's no timer queue support for ARMv6-M. This
> may change in the future.
> **NOTE**: When the `timer-queue` feature is enabled you will *not* be able to
> use the `SysTick` exception as a hardware task because the runtime uses it to
> implement the global timer queue.
To be able to schedule a software task the name of the task must appear in the To be able to schedule a software task the name of the task must appear in the
`schedule` argument of the context attribute. When scheduling a task the `schedule` argument of the context attribute. When scheduling a task the