Hi,
Is there a way to detect missed interrupts when TimerA is used in compare mode ?
Something similar to the COV bit in capture mode.
Thanks
How to detect missed interrupts with TimerA in compare mode ?
Started by ●March 29, 2009
Reply by ●April 2, 20092009-04-02
Second try...
--- In m..., "distantship101" wrote:
>
> Hi,
>
> Is there a way to detect missed interrupts when TimerA is used in compare mode ? Something similar to the COV bit in capture mode.
>
> Thanks
>
--- In m..., "distantship101" wrote:
>
> Hi,
>
> Is there a way to detect missed interrupts when TimerA is used in compare mode ? Something similar to the COV bit in capture mode.
>
> Thanks
>
Reply by ●April 2, 20092009-04-02
No,
--- In m..., "distantship101" wrote:
>
> Second try...
>
> --- In m..., "distantship101" wrote:
> >
> > Hi,
> >
> > Is there a way to detect missed interrupts when TimerA is used in compare mode ? Something similar to the COV bit in capture mode.
> >
> > Thanks
>
--- In m..., "distantship101" wrote:
>
> Second try...
>
> --- In m..., "distantship101" wrote:
> >
> > Hi,
> >
> > Is there a way to detect missed interrupts when TimerA is used in compare mode ? Something similar to the COV bit in capture mode.
> >
> > Thanks
>
Reply by ●April 3, 20092009-04-03
Thanks for the suggestions !
--- In m..., "Augusto Einsfeldt" wrote:
>
> Missing an interrupt in compare mode means two things: you did not serve the interrupt or the TAR counter missed the TACCRx value.
>
> TAR missing a value can be detected with an external reference counter. When interrupts happen normally the external counter must be inside a given window. If not, somehow the comparator missed the value and the TAR did roll-over till find the TACCR value again, resulting in higher count in the reference counter.
>
> If the system fails to serve an interrupt it could happen only if your interrupt service routine takes more time than the intervall between two interruptions. This can happen also when some other part of the program disables the interrupts for long time then several more priority interrupt pending services must be handled before the TimerA request.
> Again, an external event must be used to verify. If you need this only for development phase you can toogle a pin every time happens an interrupt in TimerA. Then use a digital osciloscope in infinite persistence mode to see if some toogle is delayed.
> Moreover, you can use this signal to trigger another channel where another pin is toogled in different routines in your software. then you can see which one is causing the delay.
>
> Maybe before that you can check device's errata reports. There are some known problems for some devices regarding Timer A.
>
> -Augusto
>
>
> De:m...
>
> Para:m...
>
> Cia:
>
> Data:Thu, 02 Apr 2009 17:38:27 -0000
>
> Assunto:[msp430] How to detect missed interrupts with TimerA in compare mode ?
>
> Second try...
>
> --- In m..., "distantship101" wrote:
> >
> > Hi,
> >
> > Is there a way to detect missed interrupts when TimerA is used in compare mode ? Something similar to the COV bit in capture mode.
> >
> > Thanks
> >
>
>
>
>
>
>
>
--- In m..., "Augusto Einsfeldt" wrote:
>
> Missing an interrupt in compare mode means two things: you did not serve the interrupt or the TAR counter missed the TACCRx value.
>
> TAR missing a value can be detected with an external reference counter. When interrupts happen normally the external counter must be inside a given window. If not, somehow the comparator missed the value and the TAR did roll-over till find the TACCR value again, resulting in higher count in the reference counter.
>
> If the system fails to serve an interrupt it could happen only if your interrupt service routine takes more time than the intervall between two interruptions. This can happen also when some other part of the program disables the interrupts for long time then several more priority interrupt pending services must be handled before the TimerA request.
> Again, an external event must be used to verify. If you need this only for development phase you can toogle a pin every time happens an interrupt in TimerA. Then use a digital osciloscope in infinite persistence mode to see if some toogle is delayed.
> Moreover, you can use this signal to trigger another channel where another pin is toogled in different routines in your software. then you can see which one is causing the delay.
>
> Maybe before that you can check device's errata reports. There are some known problems for some devices regarding Timer A.
>
> -Augusto
>
>
> De:m...
>
> Para:m...
>
> Cia:
>
> Data:Thu, 02 Apr 2009 17:38:27 -0000
>
> Assunto:[msp430] How to detect missed interrupts with TimerA in compare mode ?
>
> Second try...
>
> --- In m..., "distantship101" wrote:
> >
> > Hi,
> >
> > Is there a way to detect missed interrupts when TimerA is used in compare mode ? Something similar to the COV bit in capture mode.
> >
> > Thanks
> >
>
>
>
>
>
>
>
