Look at Microchip's rfPIC series:
http://www.microchip.com/1000/pline/rfpic/index.htm
They are new and I have not used them but they sound like just what you
need.

Doug Butler
Sherpa Engineering


> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Dimitris Papavasileiou
> Sent: Sunday, September 29, 2002 12:21 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: [PIC]:PICs and RF links
>
>
> Hi,
> I want to put together a full-duplex RF link for low baud rate data
> transmission between to devices.One channel will be used for
> remote control
> and the other for telemetry.The traffic will consist of fixed-length data
> packets.Error detection is needed(a CRC should do) but packets need not be
> resent in case of an error.PICs seem to have everything I need to do
> this(UARTs for the link,ADCs for the controller etc.) but I'm not
> sure about
> how suitable they are for RF links.The requirements are:
>
> 1)a ~9600kbps(or less if necessary) full-duplex link
> 2)a ~300-500m range(more would be quite welcome)
> 3)reliability:the link should not be lost for more than a few ms while in
> range(that is it should deal with resync in case of sync loss quickly)
>
> The questions I have are:
> 1)Can the built-in UART deal with a reliable RF link (that is
> provide a more or less constant flow of data in normal
> conditions)?I'm asking
> mainly because I've read in an article somewhere on the PIClist
> faq that HW
> UARTS aren't best suited for RF transmission).Also in case of a
> framing error
> what is the best way to resync the channels.I assume that the method
> described in article on synchronizing at the byte level will work with
> PICs(will it? some assumptions were made on the UART behavior)
> but how does
> the receiver let the transmitter know that sync was
> lost.Obviously we can't
> depend on the second channel because (in a very bad day) they
> might loose sync
> simultaneously.
> 2)What other things should I look out for?Like using Manchester
> code or not(I
> assume this is necessary as some transmission might include long 1 or 0
> strings which would result in clock drift),how the physical link should be
> established(FM RF,RF modem chip),etc.
> 3)Out of curiosity.If all the above is possible and doesn't cost
> a fortune(it
> shouldn't) why do all commercial remote controls(RC cars etc.)
> use one analog
> channel per 'stick' instead of just reading a bunch of data with an MC and
> send it as digital data packets(like I want to do).It would give
> you as many
> channels as you can use with a 9600kbps link.
>
> Thanks in advance,
> Dimitris
>
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