Subject:
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Re: Light Sensor help
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 10 Apr 2002 00:06:55 GMT
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Original-From:
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T. Alexander Popiel <popiel@wolfskeep.#saynotospam#com>
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Viewed:
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536 times
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In message: <GuBJ2q.HLH@lugnet.com>
"John Barnes" <barnes@sensors.com> writes:
>
> Wow! That is very interesting. I wonder if the whole thing is synchronous
> and based on the 3mS sensor read cycle? This would mean that every process
> gets one of its byte codes "done" during this periodic 3mS spring-clean cycle.
Yes, it all appears to be synchronous. However, only one bytecode
instruction is run in any given 3ms; any active tasks interleave their
instructions. If you have two tasks running, they will each be getting
an instruction every other 3ms. If you have three tasks, each one will
get one instruction every third 3ms timeslice.
> Personally, I think 330 byte codes per second is very slow. Any attempt
> at a series evaluation of trig function would take seconds!
Yeah, but why are you doing trig via series evaluation, instead of just
doing a table lookup? For that matter, do you really need the trig at
all?
> It might also explain why my array initialisation routine caused the RCX
> to go dead for a second or so after pressing the run button. The routine
> to access each memory location as a set of 8 two bit locations (for mapping
> purposes) required a modest number of instructions per two bit access!
Oh, yeah. Don't do it that way... figure out the full 16 bit values
for initialization during compilation, not at runtime. Ugh.
In fact, do all of your heavy thinking before it's downloaded into the
RCX. The RCX doesn't have the memory or the speed to do anything
computationally interesting... asking it to do such is a sure path to
disappointment.
- Alex
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Message has 1 Reply:
 | | Re: Light Sensor help
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| (...) Well, I can think of lots of reasons why you might want trig - if you know what direction you are moving in and how far you've travelled, trig will let you figure out where you are relative to where you started. Using an NQC lookup table isn't (...) (22 years ago, 10-Apr-02, to lugnet.robotics)
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Message is in Reply To:
| | Re: Light Sensor help
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| (...) Wow! That is very interesting. I wonder if the whole thing is synchronous and based on the 3mS sensor read cycle? This would mean that every process gets one of its byte codes "done" during this periodic 3mS spring-clean cycle. I guess the (...) (22 years ago, 9-Apr-02, to lugnet.robotics)
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