[Discuss-gnuradio] Updating old 802.15.4 code to latest release

[Leslie Choong]

Hi everyone,
I'm currently updating Thomas Schmid's old 802.15.4 demodulation code.
It has been tested and works with at least revision 7596 of the
gnuradio trunk. I've been trying to update the code to work with the
latest release of Gnuradio (3.1). I've looked at examples converting
from hier_block to hier_block2 and flow_graph to top_block. I've
implemented those changes but still run into this error:

python: /usr/include/boost/shared_ptr.hpp:375: T*
boost::shared_ptr<T>::operator->() const [with T = gr_basic_block]:
Assertion `px != 0' failed.

Searches for this error on the list did not turn up much. I was
wondering if there was anything else that I missed. I've been banging
my head on the wall about this trying to figure out a fix. I jumped
into gdb and found that the code was crashing when trying to flatten
the flow_graph. I turned on debugging messages for
gr_hier_block2_detail.cc and here is the result of that:

connecting: ieee802_15_4_demod(3):0 -> sos_packet_sink(8):0
connect: src is hierarchical, setting parent to 0x89e3d00
connecting: usrp1_source_c(1):0 -> pwr_squelch_cc(9):0
connecting: pwr_squelch_cc(9):0 -> ieee802_15_4_demod_pkts(2):0
connect: dst is hierarchical, setting parent to 0x88bc270
start: entered
flattening top_block
Flattening edge usrp1_source_c(1):0->pwr_squelch_cc(9):0
Flattening edge pwr_squelch_cc(9):0->ieee802_15_4_demod_pkts(2):0
Resolving endpoint ieee802_15_4_demod_pkts(2):0 as an input, recursing
Resolving port 0 as an input of ieee802_15_4_demod_pkts
python: /usr/include/boost/shared_ptr.hpp:375: T*
boost::shared_ptr<T>::operator->() const [with T = gr_basic_block]:
Assertion `px != 0' failed.
Aborted

I have attached a patch for anyone who wants to look further. If you'd
like to see all the code you can follow these steps to try it out
yourself:
svn checkout svn://acert.ir.bbn.com/svn/gr-ucla
cd gr-ucla/trunk
(copy changes.diff to this directory)
patch -p0 -i changes.diff

Then build it all:
./bootstrap && ./configure && make
sudo make install

then:
cd src/examples
./cc2420_rxtest.py


If you have any comments or leads on something else that I should look
into I would really appreciate hearing it. Thanks for all your help!
-Leslie Choong

changes.diff
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