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On Fri, 3 May 2002, Samuel Winchenbach wrote:
> I recently adopted legOS as my development environment and I have to say I
> tremendously impressed. Thanks to everyone who has worked so hard on it.
> It is really a first class, grade A product.
>
> Is sys_timer accurate to within 1 ms?
Yes. It is updated from an interrupt routine that fires every 1 ms (IIRC).
However....
> unsigned long timer_str;
> time_str = sys_time;
> wait_event(... );
> time_str = sys_time - time_str;
> lcd_int((int)timer_str);
wait_event is only accurate to 20ms or so, depending on what your other
tasks do. So your timing is very accurate, but you're not timing what you
think you're timing. I seem to recall there being a thread a month or two
back which discussed how to time events more accurately, and if you really
need better than 20ms accuracy, you should find some good tips there.
--
"From now on, we live in a world where man has walked on the moon.
And it's not a miracle, we just decided to go." -- Jim Lovell
Mike Ash - <http://www.mikeash.com/>, <mailto:mail@mikeash.com>
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| I recently adopted legOS as my development environment and I have to say I tremendously impressed. Thanks to everyone who has worked so hard on it. It is really a first class, grade A product. Is sys_timer accurate to within 1 ms? unsigned long (...) (22 years ago, 3-May-02, to lugnet.robotics.rcx.legos)
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