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 Robotics / RCX / legOS / 358
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Subject: 
Re: LNP - lets get coding.
Newsgroups: 
lugnet.robotics.rcx.legos
Date: 
Sat, 31 Jul 1999 22:08:36 GMT
Viewed: 
1069 times
  
Kevin Baker <kevin.baker@racalitsec.com> wrote:
In lugnet.robotics.rcx.legos, Kekoa Proudfoot writes:
You will miss about 1 in 256 errors that you do not catch earlier using
collision detection.  I think your error rate per message will be much less
than 1 in 256 if you (can?) get the collision detection code right.

But we shouldn't argue the point.  Somebody should just code it and try
it.  Practice will show whether a CRC8 is sufficient or whether a CRC16
will be required.

Didn't mean to come across as arguing - sorry if I did!

No, you didn't - I just didn't wanted to make sure I wasn't :)

1) Line level protocol (Basic frame rx/tx with collision detection, CRC
work etc.). Has provision to send messages on request, and passes rx'ed
messages with good CRC etc. up to higher level. (i.e. it performs the
basic MAC level).

This has already been done, for Librcx at least; don't know if anybody took
a look at the code I put at:

http://graphics.stanford.edu/~kekoa/rcx/driver/

Somebody mentioned wanting to maybe take a look at that; porting to LegOS
can't take more than a day (since it didn't take more that a day to write)
:)

The code does the low-level stuff you mentioned, minus support for ports,
acks, and resends and minus "proper thread interactions" which I define to
mean proper support for threads non-busy-type waiting on serial events,
like message arrival, message send complete, or a collision detected while
sending or receiving.  This stuff all seems to fall into (2) on your list.

-Kekoa



Message has 1 Reply:
  Re: LNP - lets get coding.
 
(...) I have just grabbed a copy - will have a look! Where do you suggest we go from here? I'm up for creating an initial API and getting some code cut (Within my limits - I know little/nothing about Linux & MacOS, and as yes LegOS). However, I'm (...) (25 years ago, 1-Aug-99, to lugnet.robotics.rcx.legos)

Message is in Reply To:
  LNP - lets get coding.
 
(...) Hi, Didn't mean to come across as arguing - sorry if I did! As you say, lets get coding LNP (My assumption is that the coding bit hasn't started yet, if it has, please accept my apologies & let me know how it is going!). I guess the things (...) (25 years ago, 31-Jul-99, to lugnet.robotics.rcx.legos)

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