Hi Kevin,

Sounds simple enough.  So after your max packet length time do you check
again to see if someone else is still transmitting or just use the CRC
to validate that the message wasn't stepped on by someone else.

What you are doing is all perfectly reasonable BTW.  You have only the
time between the last time you check to see if someone was on the air
and when you start that someone else could also start.  Since that's at
the most perhaps a bit time or two,  you can be sure that whoever
stepped on your message will also find start looking after a message.

I take it then that you send an acknowledge back with for every message?

And, out of curiosity,  how do you determine if someone is transmitting?

Cheers,

John Dammeyer

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Kevin Olalde
> Sent: Monday, May 13, 2002 1:20 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE]: RF modules
>
>
> Believe me, I'm all too easy a target to drag though the mud.
>  So that said, I'm
> all for someone helping me to understand and help correct my
> mistakes (just a
> hobby, and I've got zero background in this).
>
> I did say it was simple, all I do is check to see if there is
> traffic already
> being transmitted before I try to transmit.  I check by just
> sampling the
> received RF data for a few bits worth of time.  If I can
> receive some data
> (variations in the bit stream), I just wait for the max
> packet length (all my
> packets are the same size) and try again, checking for data
> before each send
> attempt.  That with a CRC16 is what I mean by simple.
>
> Ready for semantic and technique corrections.
>
> Thanks,
> Kevin
>
>
> John Dammeyer wrote:
> >
> > Hi Kevin,
> >
> > Tell us how you went about doing collision detection.
> >
> > Thanks.
> >
> > John Dammeyer
> >
>
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