Whats allowed in the Init() task

[Joel Sherrill]

The clock driver initialization should handle things.

Setting the time of day has no impact on the clock tick working. Having a wall time is independent of interval time.

Your tick rate is OK. The overhead is quite low. I have seen similar CPU speeds use 250 microsecond tick rate and still function OK.

The interrupt is either stuck and not clearing .. No interrupt stack.. Etc.

--joel

Matthew J Fletcher <amimjf at gmail.com> wrote:



Hi,

Sorry all, i was placing breakpoints inside rtems which i have built with -Os, so i got the wrong idea. Checking the return code from rtems_clock_set() shows it works with the ticker example time setup.

I think my issue is that as soon as the 10ms ISR calls rtems_clock_tick() no tasks get scheduled, not the idle routine, not even the Init() task. When i halt execution in the debugger i only ever see the callstack from of the ISR calling rtems_clock_tick();

I have a 20Mhz ARM7TDMI board so a 10ms call to rtems_clock_tick should just take a few microseconds.

I use,.

#define CONFIGURE_MICROSECONDS_PER_TICK 10000
#define CONFIGURE_TICKS_PER_TIMESLICE 50

I guess there is some pre-requisite i need to setup before i call rtems_clock_tick() the first time. I guessed it was having the clock set as various bits of code check _TOD_Is_set but i call rtems_set_clock() before i enable the tick ISR.



On 1 March 2013 17:10, Joel Sherrill <joel.sherrill at oarcorp.com<mailto:joel.sherrill at oarcorp.com>> wrote:
On 3/1/2013 10:56 AM, Matthew J Fletcher wrote:
Gedare,

Yes the "hello" example works fine. I just tried the "ticker" example, but rtems_clock_set() returns RTEMS_INVALID_CLOCK. Odd, maybe the samples dont get tested very often.

They get run all the time. I am heading off for the weekend but will try to
run it on something I have a simulator for.

It _TOD_Validate() is rejecting the time set in the example, and i am literally using the code from the example. Its returning false at the first 'if' test, the big one checking against the constants.

Is the test for 'the_tod->year < TOD_BASE_YEAR' correct given then are equal at 1988 ?

Yes.

On 1 March 2013 15:40, Gedare Bloom <gedare at rtems.org<mailto:gedare at rtems.org>> wrote:
On Fri, Mar 1, 2013 at 9:07 AM, Matthew J Fletcher <amimjf at gmail.com<mailto:amimjf at gmail.com>> wrote:
> Hi,
>
> Do rtems applications normally create a new task straight away in Init() ? i
> ask because i seem to get stuck with no threads being scheduled after the
> first Clock_isr.
>
By the time Init gets executed the entire application stack should be
set up and multithreading/interrupts should work fine. Init can either
create new tasks, or execute the workload directly.

> So after boot_card() completes rtems context switches into Init(), there i
> setup my 10ms tick ISR which calls rtems_clock_tick(). But the original
> thread Init() never gets scheduled again after the first call to
> rtems_clock_tick(). I've used JTAG to place breakpoints and i can see the
> code in Init() is not being run.
>
I don't understand what you mean about Init setting up the clock tick.
The ISR for clock handling should be installed during rtems
initialization when the clock driver is installed. Have you
successfully executed the "hello" sample on your board? If so the next
one to test is ticker, which should give you an idea of whether the
clock tick + context switch is working.

-Gedare

> I can see the ISR is being called and the interrupt acknowledged due to
> breakpoints there.
>
> Interestingly although i am using the arm-rtemseabi4.11-gdb 'info threads'
> only shows the current context of the ISR not the Init() thread, that might
> be a different issue though.
>
>
> regards
> ---
> Matthew J Fletcher
>
>
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>



--

regards
---
Matthew J Fletcher




--
Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill at OARcorp.com<mailto:joel.sherrill at OARcorp.com>        On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
Support Available                (256) 722-9985



--

regards
---
Matthew J Fletcher

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