Jim,
what i am doing in codifing 1 byte as manchester (1-0 or 0-1) and
then sending it over the uart ,so it is actually working as an uart, thas
why it seems not to work. I've understood it now. I'll use software
manchester
Regards
Javier
-----Mensaje original-----
De: Jim Wagner [mailto:jim_d_wagner@applelinks.net]
Enviado el: Martes, 22 de Marzo de 2005 02:59 p.m.
Para: AVR-Chat@yahoogroups.com
Asunto: Re: [AVR-Chat] RF link
I'm a little confused. You said,
earlier, I think, that youDe: Jim Wagner [mailto:jim_d_wagner@applelinks.net]
Enviado el: Martes, 22 de Marzo de 2005 02:59 p.m.
Para: AVR-Chat@yahoogroups.com
Asunto: Re: [AVR-Chat] RF link
are using manchester coding. That really does not fit with
"UART". Trying to use a UART with manchester seems like a
real problem. I'd do it all in software.
Jim
On Tue, 22 Mar 2005 13:39:40 -0300
"Javier Fiasche" wrote:
> That's right the uart ist triggering on noise.
> Unfortunatelly my reciever does not have signal strength
> output. I am using
> a very cheap
> Yong Horng reciver and transmitter (not a transciver).
>; I would need to detect a real transmition and to reject
> noise, but
> digitally, ideas???
> I tried transmitting a Hi level before setting the uart
> to transmitt, and
> trying to detect this continuos hi level on the reciver
> before setting the
> reciever uart to recive, But it doesn't work that
> fine............
> Thanks
> Javier
>
> -----Mensaje original-----
> De: Bruce Parham [mailto:obparham@jpl.nasa.gov]
> Enviado el: Martes, 22 de Marzo de 2005 01:29 p.m.
> Para: AVR-Chat@yahoogroups.com
> Asunto: Re: [AVR-Chat] RF link
>
>
>
>
> Javier Fiasche wrote:
> >
> > Hi everybody, i'm having trouble.....
> >
> > I am trying to transmit data over Rf using 2
> atmega8l(via USARt) and
> 433Mhz
> > transmitter and reciver module. One will work as
> transmiter and the other
> as
>; > reciever. The transmiter will send a code composed of:
> > -----------------------------
> > | SYNC |Package|CHECKSUM|end|
> > -----------------------------
> > all of this coded as manchester. Afer sending the
> package, the mega8 will
> > shut down the transmitter until next transmition.
> > The reciever would listen to the reciver module only
> when it is desired,
> > selecting this with a pushbutton.When i dont want to
> listen, i shut down
> the
> > 433 reciver module
> > Here is the problem:
> > i dont seem to sincronice the transmitter and
> the reciver usart,
> because
> > when the transmitter is off and the reciever is on i
> keep getting and
> > Framming error.
> > i've tried listening to the RXd pin, with the
> RXEN=0, till i get a
> > long enought "1" and then set the RXEN=1, but this seem
> to have no
> > effect.........
> > Any ideas of how to sincronice them????????????
> >
> > Thanks
> > Javier
>
> Sounds like the rx doesn't have any squelch and the uart
> is triggering on
> noise.
> I don't know what kind of receiver you're using but, if
> it has a RSS (Rx Sig
> Strength)
> line, you could use that to enable/disable the rx uart.
> (You may need to use
> the
> analog comparator on the RSS signal.)
>
> Bruce
>
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