Re: [Discuss-gnuradio] CC1101 GFSK packet decode with variable length

[Julian Arnold]

Hey Bob,

there is plenty of documentation on this topic you can check out under 
[1,2].
Especially, the Header Payload Demuxer (HPD) [3] should be worth a look 
if you are dealing with packetized variable length data.

Hope those pointer can get you started. If you have further questions 
after going through those pages, let me know.

Cheers,
Julian

[1] https://www.gnuradio.org/doc/doxygen/page_packet_data.html
[2] https://www.gnuradio.org/doc/doxygen/page_packet_comms.html
[3] 
https://www.gnuradio.org/doc/doxygen/classgr_1_1digital_1_1header__payload__demux.html

On 31.12.18 01:00, Alban Meffre wrote:
> Hi
> I would like to decode a simple GFSK packet
>
> here is the packet structure :
> preamble : AAh x 4
> sync word : D391h
> length byte : 1 byte
> payload : 1 to 64 bytes
> CRC : 2 bytes
>
> TX : arduino + CC1101 module, 2GFSK, 100kbps, excursion 50kHz, carrier 
> 433 MHz
> RX : RTLSDR
>
> until now i was able to demodulate the signal and add a "sync" tag using 
> the correlate access code.
>
> my goal is to extract the payload and send it to a file or a socket.
> is there a simple way to do that without writing my own block ?
>
> i can't go further, because i do not manage to find the info i need
> i do not know where to start : stream, tagged stream, PDU, messages, etc..
> i do not figure out how to use these tag for variable length. nothing 
> clear in the doc
>
> i'd be glad if someone helps me
> best regards
> bob
>
>
>
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