Re: [Discuss-gnuradio] Problem loading Python block

[Tom Rondeau]

On Tue, Jan 29, 2013 at 7:40 AM, Nemanja Savic <address@hidden> wrote:

I'm not sure what you mean by "load gr.basic_block." Do you mean inherit from?

I want to make my block which very similar to packet deframer. Here is th code:

class packet_tst(gr.hier_block2):
    def __init__(self, access_code=None, threshold=-1):

        gr.hier_block2.__init__(
                self,
                "packet_tst",
                        gr.io_signature(1, 1, 1),  # Input signature
                        gr.io_signature(0, 0, 0) # Output signature
        )
       
        if not access_code:
            access_code = packet_utils.default_access_code
        if not packet_utils.is_1_0_string(access_code):
            raise ValueError, "Invalid access_code %r. Must be string of 1's and 0's" % (access_code,)

        if threshold == -1:
            threshold = 12              # FIXME raise exception

        msgq = gr.msg_queue(4)          # holds packets from the PHY
        self.correlator = gr_digital.correlate_access_code_bb(access_code, threshold)
       
        self.framer_sink = gr.framer_sink_1(msgq)
        self.connect(self, self.correlator, self.framer_sink)
       
        self.hlp_blk = helper_block(msgq)

in the same file is also defined class helper_block in this way:

class helper_block(gr.basic_block):
    def __init__(self, msgq):
        gr.basic_block.__init__(
            self, name = "helper_block",
            in_sig = None, out_sig = None
        #    num_msg_outputs = 1
        )
   
    self._msgq = msgq
   
    def work(self, input_items, output_items):
        while True:
            try: msg = self._msgq.delete_head()
            except: return -1
            print "Message received"

I have no idea what files these are from. Are they part of the GNU Radio source code? I can't find references to them.

 

 

when I try to run test or flowgraph, I get this error:

 in <module>
    class helper_block(gr.basic_block):

AttributeError: 'module' object has no attribute 'basic_block'

-- Process completed
***Failed

0% tests passed, 1 tests failed out of 1

Sounds like you don't have something installed correctly. You wouldn't normally be inheriting straight from gr_basic_block, but you should be able to.

 

And in tutorial on how to write signal processing block, it is stated to use gr.basic_block.

Which tutorial? Again, I don't think this is in the main GNU Radio source, so please point out where you are getting this from.

Tom