Timer driver vs. timer manager, etc.
Kenneth Peters
Kenneth.J.Peters at jpl.nasa.gov
Thu Jun 5 18:08:18 UTC 2003
I want to make sure I understand the timer and clock elements of RTEMS
correctly, since some of the same terms are used in different places, with
no real connection between them (I think). Please comment on the following:
The "Timer Driver" referred to in the "BSP and Device Driver Development
Guide" is only used by the provided OS test suite, and has nothing to do
with the "Timer Manager" from the "RTEMS C User's Guide".
The "Timer Manager" does need the "Clock Driver" from the "BSP and Device
Driver Development Guide", as does the "Clock Manager".
The "Rate Monotonic Manager" needs the "Timer Manager" and thus the "Clock
Driver" (or does the RMM use the "Clock Driver" directly?). The "Task
Manager" needs the "Timer Manager" (or does the Task Manager use the "Clock
Driver" directly?) only if timeslicing or delay functions are needed?
The "Real-Time Clock Driver" from the "BSP and Device Driver Development
Guide" is not actually required for anything. If it is provided, the user
can call its functions to synchronize the "Clock Manager" and the RTC
device, or as substitutes for some of the "Clock Manager" functions.
Thanks,
Ken Peters
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