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 Robotics / RCX / 1386
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Subject: 
Re: RCX IR protocol
Newsgroups: 
lugnet.robotics.rcx
Date: 
Tue, 4 Sep 2001 13:25:07 GMT
Viewed: 
2268 times
  
Hi,

Juergen has done a small mistake in his example.
So for example    ~f7=~11110111=00001000=10.

Better it should be ~f7=~11110111=00001000=08.

If you want to get a little bit of math you may add every number to its
complement and you will always get ff for the result. If we take Juergen's
example it looks like the following

f7 + ~f7 = 11110111 + 00001000 = 11111111 = ff = 255
|          |                                |    |
|          binary number format             |    decimal number format
|                                           |
hex number format                           hex number format

Ralf

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Ralf Krause
Bertha-von-Suttner-Gesamtschule Dormagen
Marie-Schlei-Strasse 6
41542 Dormagen
Germany

http://www.shuttle.schule.de/ne/bvsdormagen
mailto:nospam.krause.ralf@web.de


please delete the "nospam." in front of
my real email address before you answer
____________________________________________


on 2001-09-04 13:31 Uhr, Juergen Stuber at stuber@loria.fr wrote:

Seanna or Steve or Trevyn or Nicholas <swatsons@home.com> writes:

Hi all,

I was looking at the IR protocol described at
http://graphics.stanford.edu/~kekoa/rcx/, and i dont quite understand.

Take a look at http://graphics.stanford.edu/~kekoa/rcx/protocol.html

What is the packet header?

55 ff 00

what does the ~ mean? (eg "RCX reply opcode is always ~query opcode")

complement, i.e. invert every bit separately.

So for example ~f7=~11110111=00001000=10.

I am asking because i am writing an application that would do something
similar to the remote control.

Good luck and show it to us when you are done

Jürgen



Message is in Reply To:
  Re: RCX IR protocol
 
(...) Take a look at (URL) (...) 55 ff 00 (...) complement, i.e. invert every bit separately. So for example ~f7=~11110111=00001000=10. (...) Good luck and show it to us when you are done Jürgen (23 years ago, 4-Sep-01, to lugnet.robotics.rcx)

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