Subject:
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Re: IR communications related questions (long)
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Newsgroups:
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lugnet.robotics.rcx.pbforth
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Date:
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Tue, 2 May 2000 04:23:32 GMT
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Reply-To:
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sjm@judgementSTOPSPAMMERS.com
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Viewed:
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1681 times
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Ralph Hempel wrote:
> Well, you'll find that the core of all your work will
> be done with 30 or so basic words that are standard
> in any Forth implementation. Putting out a wordlist
> would be a bit of an undertaking, but there's been enough
> demand that it will eventually get done. You can scan through
> the h8hforth.asm source and get a good head start on
> the job if you're interested :-)
I guess what I am really looking for is some kind of quick reference
guide. If Hendtlass's book is compatible then I can use his appendix.
> > o - Are the pbForth tasking words standard?
>
> No, they are hForth extensions. I've found that tasking is
> largely unnecessary for most robotic applications. It's nice
> to use after you're more experienced with all of the real-time
> issues.
Gaining experience with real time issues is not exactly my problem :)
> There is no ISR. You EMIT bytes as needed. EMIT blocks until
> the UART accepts the byte into the buffer. This may be
> well before any bits actually go out the door. A subsequent
> EMIT will wait (block) until the DUART is ready to go.
I guess I need to look at the implementation so I can create a polling
word that check whether the UART buffer is empty. It looks like that
would be about the top half of TXStore.
> IR bytes are read only when the interpreter is waiting for
> them. If your application is in a tight loop waiting for a
> sensor press, no IR will happen.
Doesn't it read at least one byte into the UART read buffer? I'd
like to believe that the UART could be processing one byte while
the code checks a few other things.
> The IR is handled by a custom IR driver, and I'd like to make it
> interrupt driven and buffered eventually...
The legOS serial driver (lnp-logical) should be good documentation
on how to do this. It is interrupt driven although this can't be fun
stuff
to debug. You would have to extract the serial stuff from the lnp stuff
This chips serial stuff seems pretty simple to use.
Well here I go into the .asm files. I really had intended to learn m4 by
now anyway. What is it with the echo anyway? Does it see its own IR
or something? Or is this something the tower does? Does this mean that
transmit and receive use the same IR frequency and the link is half
duplex? Hmm...
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