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 Robotics / RCX / legOS / 1261
1260  |  1262
Subject: 
Re: light sensor problem?
Newsgroups: 
lugnet.robotics.rcx.legos
Date: 
Mon, 24 Jul 2000 01:52:16 GMT
Viewed: 
5578 times
  
> I see. Interesting post. Like Kekoa points out, though, we have no actual
> proof that this occurs (even though his logic does seem pretty dead on.)

This is why I want to measure things in our lab at work ;)

> time_t current_time = sys_time;
> while (sys_time < current_time + the amount of time I want to wait)
> {
>  do nothing;
> }
> 
> It's not pretty, but it is functional.

And keeps lower prio tasks from running, which they could do if we slept...

> I have absolutely no idea about how efficient the compiler is. I suppose,
> worst comes to worst, we can always re-implement and then test.

Oh well, there are some optimizations missing. I just looked at the code
generated by ad_value[0] = AD_C >> 6. egcs is generating a loop with
shlr and rotxr run 6 times. You could use 2 left shifts and swap high and low
registers for this if you are smart.

> One philosophical note: part of what I like about legOS is the very
> low-level, close to the metal feel that you can get from it. This includes
> overly fast sampling, raw sensor values, etc. While I agree that the base
> of the OS needs work, and in nearly all use these "extreme" cases are
> irrelevant, I'd still argue against doing anything that removes too much
> power from the programmer.* Not that I think that these changes would do
> such a thing, but in general this is to be avoided.
> 
> *Yes, I am still bitter that I can no longer control On/Off and Run :)

Oh, if it's only this: look at the sample code I wrote for the sensors and
do it like this: Steal the interrupt from legOS ;) Yes, I know this is not
nice... No, don't take this to serious, it's 4 in the morning and I need
some sleep.


Eddie C. Dost
ecd@skynet.be



Message has 1 Reply:
  Re: light sensor problem?
 
(...) Right. I made the connection between Kekoa saying "I need to test" and you saying "I will test" right /after/ sending the message, of course :) (...) True. (...) I figured this would be the case. gcc is a wonderful tool, but it does tend to (...) (26 years ago, 24-Jul-00, to lugnet.robotics.rcx.legos)

Message is in Reply To:
  Re: light sensor problem?
 
(...) proof that this occurs (even though his logic does seem pretty dead on.) (...) Well, we do... time_t current_time = sys_time; while (sys_time < current_time + the amount of time I want to wait) { do nothing; } It's not pretty, but it is (...) (26 years ago, 24-Jul-00, to lugnet.robotics.rcx.legos)

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