[ECOS] timer interrupt help

Jeffrey Krasky jkrasky@cs.umn.edu
Sat Apr 25 07:45:00 GMT 2009


I'm doing this on a windows machine with Intel hardware. Considering all 
of the abstractions between the hardware, such as windows --> cygwin --> 
eCos, do I really stand a chance of getting 1ms periods, or will I only 
get something *close* like 1ms 200us, then 1us 150us, etc?

What I really want is a perfect 1 millisecond, with only being off by a 
few hundred nanoseconds.

Thanks,



Jeff



On Fri, 24 Apr 2009, Libo Wang wrote:

> Jeff
> The precise will decided by your hardware timer setting. Generally,
> hardware timer run at ns level.
> And you can set how many hardware cycles the timer interrupt will be
> triggered.
> For your case, you can refer the systems clock implement.  It should in
> clock.cxx.
>
> And I guess if you using such precise will caused high CPU load.
>
> BR
> Thx
> Libo Wang
>
> -----Original Message-----
> From: ecos-discuss-owner@ecos.sourceware.org
> [mailto:ecos-discuss-owner@ecos.sourceware.org] On Behalf Of Jeffrey
> Krasky
> Sent: Friday, April 24, 2009 10:25 PM
> To: ecos-discuss@sourceware.org
> Subject: [ECOS] timer interrupt help
>
> Hi,
> I've been reading about interrupts and how to create/attach them in
> eCos.
> There is still one piece of information that I am not sure about.
>
> My goal is to have a timer go off every millisecond, as precise as
> possible. Is there a counter that I can register my ISR with so that
> when
> the counter reaches a value that's equivalent to 1ms in ticks, it will
> call my ISR? Or do I have to monitor the clock myself? I feel if I have
> to monitor the clock myself I will not achieve 1ms granularity.
>
> Thanks,
>
>
>
> Jeff
>
>
>
> --
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> and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
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