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RE: timer interrupt help


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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