Subject:
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Re: IR header how optional
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Sun, 2 Feb 2003 18:26:45 GMT
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Viewed:
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3442 times
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"Pat LaVarre" <ppaatt@aol.com> wrote:
> > > in... Kekoa's firmdl3.tar.gz ... the four byte
> > > packet x 10 FE 10 FE, equal to the seven byte packet
> > > x 55 FF 00 10 FE 10 FE with the header deleted
> >
> > I haven't seen anything in the docs to indicate
> > that the RCX should make some reply to that
> > sequence.
>
> Yep. But via our solid new reply framing code, thanks again, now I can • see ...
>
> > I would expect that raw byte sequence to be ignored
> > by the RCX
>
> Nope. At least not here: now that I look, I see my RCX often doesn't • require
> the PC to send x 55:FF:00.
That's very interesting. And, I've managed to get replies to "headerless"
packets as you describe, however...
> IR command packets like x 10:FE 10:FE PBAliveOrNot and x 06:F9 01:FE 0A:F5
> 34:CB PlayTone work fine without headers, provided I toggle the op & sum • with
> mask x08 and/or precede a repeated command with PBAliveOrNot.
I still don't see any response to 0x10 0xFE 0x10 0xFE. The even bytes
(0xFE) are not the complement of the odd ones (0x10), so I'm still
interested in knowing the purpose of that byte sequence in
rcx_wakeup_tower() of rcx_comm.c...
OTOH, the raw byte sequence 0x10 0xEF 0x10 0xEF *does* get
the RCX to respond with 0x55 0xFF 0x00 0xEF 0x10 0xEF 0x10.
> I wonder what purpose does the x 55:FF:00 header ever serve. I see the • web
> speaks of warming up IR electronics. I wonder if that's all this does, • and if
> we're warming up sender electronics or receiver electronics or both.
Maybe not "warming up" exactly, but charging some capacitors that
are used to offset ambient IR levels.
> Omitting the header saves 137ms per packet...
Yes, this could come in handy, I'm sure.
Mark
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Message has 1 Reply:
 | | Re: IR header how optional
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| (...) Yes, I misspoke, indeed from a place of incomplete understanding, sorry, thanks for helping. I did mean to say x 10:EF 10:EF works fine. Like you, if I try x 10:FE 10:FE, I see it echoed but then I see no further reply. And yes x 10:FE 10:FE (...) (22 years ago, 3-Feb-03, to lugnet.robotics.rcx)
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Message is in Reply To:
| | IR header how optional
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| (...) Yep. But via our solid new reply framing code, thanks again, now I can see ... (...) Nope. At least not here: now that I look, I see my RCX often doesn't require the PC to send x 55:FF:00. IR command packets like x 10:FE 10:FE PBAliveOrNot and (...) (22 years ago, 2-Feb-03, to lugnet.robotics.rcx)
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