[Discuss-gnuradio] gain slider issues

[Eric Hill Matlis]

I'm having some python coding issues with a slider I'm trying to 
implement.  The code is based on usrp_wfm_rcv_pll.py, which uses the 
powermate to adjust either frequency or volume.  I would like to replace 
the volume slider with a gain slider, which exists in the original but 
which is not controlled by the powermate.

My code is below, and the symptoms are that while the new gain slider 
moves, the value shown does not update until I click the powermate button 
to switch to frequency control.  Any suggestions?

Thanks!

eric

        # control area form at bottom
        self.myform = myform = form.form()

        hbox = wx.BoxSizer(wx.HORIZONTAL)
        hbox.Add((5,0), 0)
        myform['freq'] = form.float_field(
            parent=self.panel, sizer=hbox, label="Carrier Freq", weight=1,
            callback=myform.check_input_and_call(_form_set_freq, 
self._set_status_msg))

        hbox.Add((5,0), 0)
        myform['freq_slider'] = \
            form.quantized_slider_field(parent=self.panel, sizer=hbox, 
weight=3,
                                        range=(.5e6, 3.5e6, 0.001e6),
                                        callback=self.set_freq)
        hbox.Add((5,0), 0)
        vbox.Add(hbox, 0, wx.EXPAND)

        hbox = wx.BoxSizer(wx.HORIZONTAL)
        hbox.Add((5,0), 0)

        myform['gain'] = \
            form.quantized_slider_field(parent=self.panel, sizer=hbox, 
label="Gain",
                                        weight=3, 
range=self.subdev.gain_range(),
                                        callback=self.subdev.set_gain)
        hbox.Add((5,0), 0)
        vbox.Add(hbox, 0, wx.EXPAND)

        try:
            self.knob = powermate.powermate(self.frame)
            self.rot = 0
            powermate.EVT_POWERMATE_ROTATE (self.frame, self.on_rotate)
            powermate.EVT_POWERMATE_BUTTON (self.frame, self.on_button)
        except:
            print "FYI: No Powermate or Contour Knob found"


    def on_rotate (self, event):
        self.rot += event.delta
        if (self.state == "FREQ"):
            if self.rot >= 3:
                self.set_freq(self.freq + .001e6)
                self.rot -= 3
            elif self.rot <=-3:
                self.set_freq(self.freq - .001e6)
                self.rot += 3
        else:
            step = self.subdev.gain_range()[2]
            if self.rot >= 3:
                self.set_gain(self.gain + step)
                self.rot -= 3
            elif self.rot <=-3:
                self.set_gain(self.gain - step)
                self.rot += 3

    def on_button (self, event):
        if event.value == 0:        # button up
            return
        self.rot = 0
        if self.state == "FREQ":
            self.state = "GAIN"
        else:
            self.state = "FREQ"
        self.update_status_bar ()


    def set_gain (self, gain):
        g = self.subdev.gain_range()
        self.gain = max(g[0], min(g[1], gain))
        #self.gain_control.set_k(10**(self.gain/10))
        self.myform['gain'].set_value(self.gain)
        self.update_status_bar ()

    def set_freq(self, target_freq):
        """
        Set the center frequency we're interested in.

        @param target_freq: frequency in Hz
        @rypte: bool

        Tuning is a two step process.  First we ask the front-end to
        tune as close to the desired frequency as it can.  Then we use
        the result of that operation and our target_frequency to
        determine the value for the digital down converter.
        """
        r = usrp.tune(self.u, 0, self.subdev, target_freq)

        if r:
            self.freq = target_freq
            self.myform['freq'].set_value(target_freq)         # update 
displayed value
            self.myform['freq_slider'].set_value(target_freq)  # update 
displayed value
            self.update_status_bar()
            self._set_status_msg("OK", 0)
            return True

        self._set_status_msg("Failed", 0)
        return False

    def set_gain(self, gain):
        self.gain=gain
        self.myform['gain'].set_value(gain)     # update displayed value
        self.subdev.set_gain(gain)

    def update_status_bar (self):
        msg = "Gain:%r  Setting:%s" % (self.gain, self.state)
        self._set_status_msg(msg, 1)
        self.src_fft.set_baseband_freq(self.freq)

    def gain_range(self):
        return (0, 20, 1)


************************************
Eric H. Matlis, Ph.D.
Aerospace & Mechanical Engineering Dept.
120 Hessert Center for Aerospace Research
University of Notre Dame
Notre Dame, IN 46556-5684
Phone: (574) 631-6054
Fax:   (574) 631-8355