Testcase for timed commands. That fails.

continous_frequency_hopper

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 
# Copyright 2013 Marcus Müller.
# 
# This 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.
# 
# This software 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 this software; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.

from gnuradio import gr, blocks, uhd
class continous_frequency_hopper:
    def __init__(self):
        ### Create blocks
        self._tb        = gr.top_block()
        self.src        = uhd.usrp_source(
                            "",
                            uhd.stream_args(
                                cpu_format="fc32",
                                channels=range(1) )
                            )
        self.head       = blocks.head(gr.sizeof_gr_complex, int(100e6))
        self.sink       = blocks.null_sink(gr.sizeof_gr_complex)
        self.tag_debug  = blocks.tag_debug(gr.sizeof_gr_complex, "src")
        ###setup USRP source
        self.src.set_gain(30)
        self.src.set_samp_rate(5e6)
        self.src.set_center_freq(2e9)
        ###start flowgraph
        self._tb.connect(self.src, self.head, self.sink)
        self._tb.connect(self.src, self.tag_debug)
        self._tb.start()
        ###get current timestamp
        time_now = self.src.get_time_now().get_real_secs()
        print("time: {:f} freq: {:f} MHz".format(time_now, self.src.get_center_freq()/1e6))
        time_next = time_now + 1.0
        next_spec = uhd.time_spec(time_next)
        print("next time: {:f}".format(next_spec.get_real_secs()))
        ##issue timed command
        self.src.set_command_time(next_spec)
        self.src.set_center_freq(1e9)
        print "called set_center_freq"
        self.src.clear_command_time()
        print "called clear_command_time"
        ###get current time again
        time_now = self.src.get_time_now().get_real_secs()
        print("time: {:f} freq: {:f} MHz".format(time_now, self.src.get_center_freq()/1e6))

if __name__ == "__main__":
    continous_frequency_hopper()