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Diffstat (limited to 'gr-digital/python/pkt.py')
| -rw-r--r-- | gr-digital/python/pkt.py | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/gr-digital/python/pkt.py b/gr-digital/python/pkt.py new file mode 100644 index 000000000..8650bdbb0 --- /dev/null +++ b/gr-digital/python/pkt.py @@ -0,0 +1,167 @@ +# +# Copyright 2005, 2006, 2007 Free Software Foundation, Inc. +# +# This file is part of GNU Radio +# +# GNU Radio is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3, or (at your option) +# any later version. +# +# GNU Radio is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with GNU Radio; see the file COPYING. If not, write to +# the Free Software Foundation, Inc., 51 Franklin Street, +# Boston, MA 02110-1301, USA. +# + +from math import pi +from gnuradio import gr +import gnuradio.gr.gr_threading as _threading +import packet_utils +import digital_swig + + +# ///////////////////////////////////////////////////////////////////////////// +# mod/demod with packets as i/o +# ///////////////////////////////////////////////////////////////////////////// + +class mod_pkts(gr.hier_block2): + """ + Wrap an arbitrary digital modulator in our packet handling framework. + + Send packets by calling send_pkt + """ + def __init__(self, modulator, access_code=None, msgq_limit=2, pad_for_usrp=True, + use_whitener_offset=False, modulate=True): + """ + Hierarchical block for sending packets + + Packets to be sent are enqueued by calling send_pkt. + The output is the complex modulated signal at baseband. + + @param modulator: instance of modulator class (gr_block or hier_block2) + @type modulator: complex baseband out + @param access_code: AKA sync vector + @type access_code: string of 1's and 0's between 1 and 64 long + @param msgq_limit: maximum number of messages in message queue + @type msgq_limit: int + @param pad_for_usrp: If true, packets are padded such that they end up a multiple of 128 samples + @param use_whitener_offset: If true, start of whitener XOR string is incremented each packet + + See gmsk_mod for remaining parameters + """ + + gr.hier_block2.__init__(self, "mod_pkts", + gr.io_signature(0, 0, 0), # Input signature + gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature + + self._modulator = modulator + self._pad_for_usrp = pad_for_usrp + self._use_whitener_offset = use_whitener_offset + self._whitener_offset = 0 + + if access_code is None: + 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,) + self._access_code = access_code + + # accepts messages from the outside world + self._pkt_input = gr.message_source(gr.sizeof_char, msgq_limit) + self.connect(self._pkt_input, self._modulator, self) + + def send_pkt(self, payload='', eof=False): + """ + Send the payload. + + @param payload: data to send + @type payload: string + """ + if eof: + msg = gr.message(1) # tell self._pkt_input we're not sending any more packets + else: + # print "original_payload =", string_to_hex_list(payload) + pkt = packet_utils.make_packet(payload, + self._modulator.samples_per_symbol(), + self._modulator.bits_per_symbol(), + self._access_code, + self._pad_for_usrp, + self._whitener_offset) + #print "pkt =", string_to_hex_list(pkt) + msg = gr.message_from_string(pkt) + if self._use_whitener_offset is True: + self._whitener_offset = (self._whitener_offset + 1) % 16 + + self._pkt_input.msgq().insert_tail(msg) + + + +class demod_pkts(gr.hier_block2): + """ + Wrap an arbitrary digital demodulator in our packet handling framework. + + The input is complex baseband. When packets are demodulated, they are passed to the + app via the callback. + """ + + def __init__(self, demodulator, access_code=None, callback=None, threshold=-1): + """ + Hierarchical block for demodulating and deframing packets. + + The input is the complex modulated signal at baseband. + Demodulated packets are sent to the handler. + + @param demodulator: instance of demodulator class (gr_block or hier_block2) + @type demodulator: complex baseband in + @param access_code: AKA sync vector + @type access_code: string of 1's and 0's + @param callback: function of two args: ok, payload + @type callback: ok: bool; payload: string + @param threshold: detect access_code with up to threshold bits wrong (-1 -> use default) + @type threshold: int + """ + + gr.hier_block2.__init__(self, "demod_pkts", + gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature + gr.io_signature(0, 0, 0)) # Output signature + + self._demodulator = demodulator + if access_code is None: + 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,) + self._access_code = access_code + + if threshold == -1: + threshold = 12 # FIXME raise exception + + self._rcvd_pktq = gr.msg_queue() # holds packets from the PHY + self.correlator = digital_swig.correlate_access_code_bb(access_code, threshold) + + self.framer_sink = gr.framer_sink_1(self._rcvd_pktq) + self.connect(self, self._demodulator, self.correlator, self.framer_sink) + + self._watcher = _queue_watcher_thread(self._rcvd_pktq, callback) + + +class _queue_watcher_thread(_threading.Thread): + def __init__(self, rcvd_pktq, callback): + _threading.Thread.__init__(self) + self.setDaemon(1) + self.rcvd_pktq = rcvd_pktq + self.callback = callback + self.keep_running = True + self.start() + + + def run(self): + while self.keep_running: + msg = self.rcvd_pktq.delete_head() + ok, payload = packet_utils.unmake_packet(msg.to_string(), int(msg.arg1())) + if self.callback: + self.callback(ok, payload) |