aboutsummaryrefslogtreecommitdiffstats
path: root/host/lib/usrp/dboard/db_rfx.cpp
blob: 3e7df9a39ca3892da81f1e3947af7c340bd059aa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
//
// Copyright 2010-2012 Ettus Research LLC
//
// This program 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 of the License, or
// (at your option) any later version.
//
// This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
//

// IO Pin functions
#define POWER_IO     (1 << 7)   // Low enables power supply
#define ANTSW_IO     (1 << 6)   // On TX DB, 0 = TX, 1 = RX, on RX DB 0 = main ant, 1 = RX2
#define MIXER_IO     (1 << 5)   // Enable appropriate mixer
#define LOCKDET_MASK (1 << 2)   // Input pin

// Mixer constants
#define MIXER_ENB    MIXER_IO
#define MIXER_DIS    0

// Antenna constants
#define ANT_TX       0          //the tx line is transmitting
#define ANT_RX       ANTSW_IO   //the tx line is receiving
#define ANT_TXRX     0          //the rx line is on txrx
#define ANT_RX2      ANTSW_IO   //the rx line in on rx2
#define ANT_XX       0          //dont care how the antenna is set

#include "adf4360_regs.hpp"
#include <uhd/types/dict.hpp>
#include <uhd/types/ranges.hpp>
#include <uhd/types/sensors.hpp>
#include <uhd/utils/assert_has.hpp>
#include <uhd/utils/log.hpp>
#include <uhd/utils/static.hpp>
#include <uhd/utils/algorithm.hpp>
#include <uhd/utils/msg.hpp>
#include <uhd/usrp/dboard_id.hpp>
#include <uhd/usrp/dboard_base.hpp>
#include <uhd/usrp/dboard_manager.hpp>
#include <boost/assign/list_of.hpp>
#include <boost/bind.hpp>
#include <boost/format.hpp>
#include <boost/math/special_functions/round.hpp>

using namespace uhd;
using namespace uhd::usrp;
using namespace boost::assign;

/***********************************************************************
 * The RFX Series constants
 **********************************************************************/
static const std::vector<std::string> rfx_tx_antennas = list_of("TX/RX")("CAL");

static const std::vector<std::string> rfx_rx_antennas = list_of("TX/RX")("RX2")("CAL");

static const uhd::dict<std::string, gain_range_t> rfx_rx_gain_ranges = map_list_of
    ("PGA0", gain_range_t(0, 70, 0.022))
;

static const uhd::dict<std::string, gain_range_t> rfx400_rx_gain_ranges = map_list_of
    ("PGA0", gain_range_t(0, 45, 0.022))
;

/***********************************************************************
 * The RFX series of dboards
 **********************************************************************/
class rfx_xcvr : public xcvr_dboard_base{
public:
    rfx_xcvr(
        ctor_args_t args,
        const freq_range_t &freq_range,
        bool rx_div2, bool tx_div2
    );
    ~rfx_xcvr(void);

private:
    const freq_range_t _freq_range;
    const uhd::dict<std::string, gain_range_t> _rx_gain_ranges;
    const uhd::dict<dboard_iface::unit_t, bool> _div2;
    std::string  _rx_ant;
    uhd::dict<std::string, double> _rx_gains;
    boost::uint16_t _power_up;

    void set_rx_ant(const std::string &ant);
    void set_tx_ant(const std::string &ant);
    double set_rx_gain(double gain, const std::string &name);

    /*!
     * Set the LO frequency for the particular dboard unit.
     * \param unit which unit rx or tx
     * \param target_freq the desired frequency in Hz
     * \return the actual frequency in Hz
     */
    double set_lo_freq(dboard_iface::unit_t unit, double target_freq);

    /*!
     * Get the lock detect status of the LO.
     * \param unit which unit rx or tx
     * \return sensor for locked
     */
    sensor_value_t get_locked(dboard_iface::unit_t unit){
        const bool locked = (this->get_iface()->read_gpio(unit) & LOCKDET_MASK) != 0;
        return sensor_value_t("LO", locked, "locked", "unlocked");
    }

    /*!
     * Removed incorrect/confusing RSSI calculation
     * Limited dynamic range of sensor makes this less useful
     */
};

/***********************************************************************
 * Register the RFX dboards (min freq, max freq, rx div2, tx div2)
 **********************************************************************/
static dboard_base::sptr make_rfx_flex400(dboard_base::ctor_args_t args){
    return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(400e6, 500e6), true, true));
}

static dboard_base::sptr make_rfx_flex900(dboard_base::ctor_args_t args){
    return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(750e6, 1050e6), true, true));
}

static dboard_base::sptr make_rfx_flex1800(dboard_base::ctor_args_t args){
    return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(1500e6, 2100e6), false, false));
}

static dboard_base::sptr make_rfx_flex1200(dboard_base::ctor_args_t args){
    return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(1150e6, 1450e6), true, true));
}

static dboard_base::sptr make_rfx_flex2200(dboard_base::ctor_args_t args){
    return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(2000e6, 2400e6), false, false));
}

static dboard_base::sptr make_rfx_flex2400(dboard_base::ctor_args_t args){
    return dboard_base::sptr(new rfx_xcvr(args, freq_range_t(2300e6, 2900e6), false, false));
}

UHD_STATIC_BLOCK(reg_rfx_dboards){
    dboard_manager::register_dboard(0x0024, 0x0028, &make_rfx_flex400,  "RFX400");
    dboard_manager::register_dboard(0x0025, 0x0029, &make_rfx_flex900,  "RFX900");
    dboard_manager::register_dboard(0x0034, 0x0035, &make_rfx_flex1800, "RFX1800");
    dboard_manager::register_dboard(0x0026, 0x002a, &make_rfx_flex1200, "RFX1200");
    dboard_manager::register_dboard(0x002c, 0x002d, &make_rfx_flex2200, "RFX2200");
    dboard_manager::register_dboard(0x0027, 0x002b, &make_rfx_flex2400, "RFX2400");
}

/***********************************************************************
 * Structors
 **********************************************************************/
rfx_xcvr::rfx_xcvr(
    ctor_args_t args,
    const freq_range_t &freq_range,
    bool rx_div2, bool tx_div2
):
    xcvr_dboard_base(args),
    _freq_range(freq_range),
    _rx_gain_ranges((get_rx_id() == 0x0024)?
        rfx400_rx_gain_ranges : rfx_rx_gain_ranges
    ),
    _div2(map_list_of
        (dboard_iface::UNIT_RX, rx_div2)
        (dboard_iface::UNIT_TX, tx_div2)
    ),
    _power_up((get_rx_id() == 0x0024 && get_tx_id() == 0x0028) ? POWER_IO : 0)
{
    ////////////////////////////////////////////////////////////////////
    // Register RX properties
    ////////////////////////////////////////////////////////////////////
    if(get_rx_id() == 0x0024) this->get_rx_subtree()->create<std::string>("name").set("RFX400 RX");
    else if(get_rx_id() == 0x0025) this->get_rx_subtree()->create<std::string>("name").set("RFX900 RX");
    else if(get_rx_id() == 0x0034) this->get_rx_subtree()->create<std::string>("name").set("RFX1800 RX");
    else if(get_rx_id() == 0x0026) this->get_rx_subtree()->create<std::string>("name").set("RFX1200 RX");
    else if(get_rx_id() == 0x002c) this->get_rx_subtree()->create<std::string>("name").set("RFX2200 RX");
    else if(get_rx_id() == 0x0027) this->get_rx_subtree()->create<std::string>("name").set("RFX2400 RX");
    else this->get_rx_subtree()->create<std::string>("name").set("RFX RX");

    this->get_rx_subtree()->create<sensor_value_t>("sensors/lo_locked")
        .publish(boost::bind(&rfx_xcvr::get_locked, this, dboard_iface::UNIT_RX));
    BOOST_FOREACH(const std::string &name, _rx_gain_ranges.keys()){
        this->get_rx_subtree()->create<double>("gains/"+name+"/value")
            .coerce(boost::bind(&rfx_xcvr::set_rx_gain, this, _1, name))
            .set(_rx_gain_ranges[name].start());
        this->get_rx_subtree()->create<meta_range_t>("gains/"+name+"/range")
            .set(_rx_gain_ranges[name]);
    }
    this->get_rx_subtree()->create<double>("freq/value")
        .coerce(boost::bind(&rfx_xcvr::set_lo_freq, this, dboard_iface::UNIT_RX, _1))
        .set((_freq_range.start() + _freq_range.stop())/2.0);
    this->get_rx_subtree()->create<meta_range_t>("freq/range").set(_freq_range);
    this->get_rx_subtree()->create<std::string>("antenna/value")
        .subscribe(boost::bind(&rfx_xcvr::set_rx_ant, this, _1))
        .set("RX2");
    this->get_rx_subtree()->create<std::vector<std::string> >("antenna/options")
        .set(rfx_rx_antennas);
    this->get_rx_subtree()->create<std::string>("connection").set("QI");
    this->get_rx_subtree()->create<bool>("enabled").set(true); //always enabled
    this->get_rx_subtree()->create<bool>("use_lo_offset").set(false);
    this->get_rx_subtree()->create<double>("bandwidth/value").set(2*20.0e6); //20MHz low-pass, we want complex double-sided
    this->get_rx_subtree()->create<meta_range_t>("bandwidth/range")
        .set(freq_range_t(2*20.0e6, 2*20.0e6));

    ////////////////////////////////////////////////////////////////////
    // Register TX properties
    ////////////////////////////////////////////////////////////////////
    if(get_tx_id() == 0x0028) this->get_tx_subtree()->create<std::string>("name").set("RFX400 TX");
    else if(get_tx_id() == 0x0029) this->get_tx_subtree()->create<std::string>("name").set("RFX900 TX");
    else if(get_tx_id() == 0x0035) this->get_tx_subtree()->create<std::string>("name").set("RFX1800 TX");
    else if(get_tx_id() == 0x002a) this->get_tx_subtree()->create<std::string>("name").set("RFX1200 TX");
    else if(get_tx_id() == 0x002d) this->get_tx_subtree()->create<std::string>("name").set("RFX2200 TX");
    else if(get_tx_id() == 0x002b) this->get_tx_subtree()->create<std::string>("name").set("RFX2400 TX");
    else this->get_tx_subtree()->create<std::string>("name").set("RFX TX");

    this->get_tx_subtree()->create<sensor_value_t>("sensors/lo_locked")
        .publish(boost::bind(&rfx_xcvr::get_locked, this, dboard_iface::UNIT_TX));
    this->get_tx_subtree()->create<int>("gains"); //phony property so this dir exists
    this->get_tx_subtree()->create<double>("freq/value")
        .coerce(boost::bind(&rfx_xcvr::set_lo_freq, this, dboard_iface::UNIT_TX, _1))
        .set((_freq_range.start() + _freq_range.stop())/2.0);
    this->get_tx_subtree()->create<meta_range_t>("freq/range").set(_freq_range);
    this->get_tx_subtree()->create<std::string>("antenna/value")
        .subscribe(boost::bind(&rfx_xcvr::set_tx_ant, this, _1)).set(rfx_tx_antennas.at(0));
    this->get_tx_subtree()->create<std::vector<std::string> >("antenna/options")
        .set(rfx_tx_antennas);
    this->get_tx_subtree()->create<std::string>("connection").set("IQ");
    this->get_tx_subtree()->create<bool>("enabled").set(true); //always enabled
    this->get_tx_subtree()->create<bool>("use_lo_offset").set(true);
    this->get_tx_subtree()->create<double>("bandwidth/value").set(2*20.0e6); //20MHz low-pass, we want complex double-sided
    this->get_tx_subtree()->create<meta_range_t>("bandwidth/range")
        .set(freq_range_t(2*20.0e6, 2*20.0e6));

    //enable the clocks that we need
    this->get_iface()->set_clock_enabled(dboard_iface::UNIT_TX, true);
    this->get_iface()->set_clock_enabled(dboard_iface::UNIT_RX, true);

    //set the gpio directions and atr controls (identically)
    boost::uint16_t output_enables = POWER_IO | ANTSW_IO | MIXER_IO;
    this->get_iface()->set_pin_ctrl(dboard_iface::UNIT_TX, output_enables);
    this->get_iface()->set_pin_ctrl(dboard_iface::UNIT_RX, output_enables);
    this->get_iface()->set_gpio_ddr(dboard_iface::UNIT_TX, output_enables);
    this->get_iface()->set_gpio_ddr(dboard_iface::UNIT_RX, output_enables);

    //setup the tx atr (this does not change with antenna)
    this->get_iface()->set_atr_reg(dboard_iface::UNIT_TX, gpio_atr::ATR_REG_IDLE,        _power_up | ANT_XX | MIXER_DIS);
    this->get_iface()->set_atr_reg(dboard_iface::UNIT_TX, gpio_atr::ATR_REG_RX_ONLY,     _power_up | ANT_RX | MIXER_DIS);
    this->get_iface()->set_atr_reg(dboard_iface::UNIT_TX, gpio_atr::ATR_REG_TX_ONLY,     _power_up | ANT_TX | MIXER_ENB);
    this->get_iface()->set_atr_reg(dboard_iface::UNIT_TX, gpio_atr::ATR_REG_FULL_DUPLEX, _power_up | ANT_TX | MIXER_ENB);

    //setup the rx atr (this does not change with antenna)
    this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_IDLE,        _power_up | ANT_XX | MIXER_DIS);
    this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_TX_ONLY,     _power_up | ANT_XX | MIXER_DIS);
    this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_FULL_DUPLEX, _power_up | ANT_RX2| MIXER_ENB);
}

rfx_xcvr::~rfx_xcvr(void){
    /* NOP */
}

/***********************************************************************
 * Antenna Handling
 **********************************************************************/
void rfx_xcvr::set_rx_ant(const std::string &ant){
    //validate input
    assert_has(rfx_rx_antennas, ant, "rfx rx antenna name");

    //set the rx atr regs that change with antenna setting
    if (ant == "CAL") {
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_TX_ONLY,     _power_up | ANT_TXRX  | MIXER_ENB);
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_FULL_DUPLEX, _power_up | ANT_TXRX  | MIXER_ENB);
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_RX_ONLY,     _power_up | MIXER_ENB | ANT_TXRX );
    } 
    else {
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_TX_ONLY,     _power_up | ANT_XX | MIXER_DIS);
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_FULL_DUPLEX, _power_up | ANT_RX2| MIXER_ENB);
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_RX, gpio_atr::ATR_REG_RX_ONLY,     _power_up | MIXER_ENB |
            ((ant == "TX/RX")? ANT_TXRX : ANT_RX2));
    }

    //shadow the setting
    _rx_ant = ant;
}

void rfx_xcvr::set_tx_ant(const std::string &ant){
    assert_has(rfx_tx_antennas, ant, "rfx tx antenna name");

    //set the tx atr regs that change with antenna setting
    if (ant == "CAL") {
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_TX, gpio_atr::ATR_REG_TX_ONLY,     _power_up | ANT_RX | MIXER_ENB);
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_TX, gpio_atr::ATR_REG_FULL_DUPLEX, _power_up | ANT_RX | MIXER_ENB);
    } 
    else {
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_TX, gpio_atr::ATR_REG_TX_ONLY,     _power_up | ANT_TX | MIXER_ENB);
        this->get_iface()->set_atr_reg(dboard_iface::UNIT_TX, gpio_atr::ATR_REG_FULL_DUPLEX, _power_up | ANT_TX | MIXER_ENB);
    }
}

/***********************************************************************
 * Gain Handling
 **********************************************************************/
static double rx_pga0_gain_to_dac_volts(double &gain, double range){
    //voltage level constants (negative slope)
    static const double max_volts = .2, min_volts = 1.2;
    static const double slope = (max_volts-min_volts)/(range);

    //calculate the voltage for the aux dac
    double dac_volts = uhd::clip<double>(gain*slope + min_volts, max_volts, min_volts);

    //the actual gain setting
    gain = (dac_volts - min_volts)/slope;

    return dac_volts;
}

double rfx_xcvr::set_rx_gain(double gain, const std::string &name){
    assert_has(_rx_gain_ranges.keys(), name, "rfx rx gain name");
    if(name == "PGA0"){
        double dac_volts = rx_pga0_gain_to_dac_volts(gain, 
                              (_rx_gain_ranges["PGA0"].stop() - _rx_gain_ranges["PGA0"].start()));

        //write the new voltage to the aux dac
        this->get_iface()->write_aux_dac(dboard_iface::UNIT_RX, dboard_iface::AUX_DAC_A, dac_volts);

        return gain;
    }
    else UHD_THROW_INVALID_CODE_PATH();
}

/***********************************************************************
 * Tuning
 **********************************************************************/
double rfx_xcvr::set_lo_freq(
    dboard_iface::unit_t unit,
    double target_freq
){
    UHD_LOGV(often) << boost::format(
        "RFX tune: target frequency %f MHz"
    ) % (target_freq/1e6) << std::endl;

    //clip the input
    target_freq = _freq_range.clip(target_freq);
    if (_div2[unit]) target_freq *= 2;

    //rfx400 rx is a special case with div2 in mixer, so adf4360 must output fundamental
    bool is_rx_rfx400 = ((get_rx_id() == 0x0024) && unit != dboard_iface::UNIT_TX);

    //map prescalers to the register enums
    static const uhd::dict<int, adf4360_regs_t::prescaler_value_t> prescaler_to_enum = map_list_of
        (8,  adf4360_regs_t::PRESCALER_VALUE_8_9)
        (16, adf4360_regs_t::PRESCALER_VALUE_16_17)
        (32, adf4360_regs_t::PRESCALER_VALUE_32_33)
    ;

    //map band select clock dividers to enums
    static const uhd::dict<int, adf4360_regs_t::band_select_clock_div_t> bandsel_to_enum = map_list_of
        (1, adf4360_regs_t::BAND_SELECT_CLOCK_DIV_1)
        (2, adf4360_regs_t::BAND_SELECT_CLOCK_DIV_2)
        (4, adf4360_regs_t::BAND_SELECT_CLOCK_DIV_4)
        (8, adf4360_regs_t::BAND_SELECT_CLOCK_DIV_8)
    ;

    double actual_freq=0, ref_freq = this->get_iface()->get_clock_rate(unit);
    int R=0, BS=0, P=0, B=0, A=0;

    /*
     * The goal here to to loop though possible R dividers,
     * band select clock dividers, and prescaler values.
     * Calculate the A and B counters for each set of values.
     * The loop exits when it meets all of the constraints.
     * The resulting loop values are loaded into the registers.
     *
     * fvco = [P*B + A] * fref/R
     * fvco*R/fref = P*B + A = N
     */
    for(R = 2; R <= 32; R+=2){
        BOOST_FOREACH(BS, bandsel_to_enum.keys()){
            if (ref_freq/R/BS > 1e6) continue; //constraint on band select clock
            BOOST_FOREACH(P, prescaler_to_enum.keys()){
                //calculate B and A from N
                double N = target_freq*R/ref_freq;
                B = int(std::floor(N/P));
                A = boost::math::iround(N - P*B);
                if (B < A or B > 8191 or B < 3 or A > 31) continue; //constraints on A, B
                //calculate the actual frequency
                actual_freq = double(P*B + A)*ref_freq/R;
                if (actual_freq/P > 300e6) continue; //constraint on prescaler output
                //constraints met: exit loop
                goto done_loop;
            }
        }
    } done_loop:

    UHD_LOGV(often) << boost::format(
        "RFX tune: R=%d, BS=%d, P=%d, B=%d, A=%d, DIV2=%d"
    ) % R % BS % P % B % A % int(_div2[unit] && (!is_rx_rfx400)) << std::endl;

    //load the register values
    adf4360_regs_t regs;
    regs.core_power_level        = adf4360_regs_t::CORE_POWER_LEVEL_10MA;
    regs.counter_operation       = adf4360_regs_t::COUNTER_OPERATION_NORMAL;
    regs.muxout_control          = adf4360_regs_t::MUXOUT_CONTROL_DLD;
    regs.phase_detector_polarity = adf4360_regs_t::PHASE_DETECTOR_POLARITY_POS;
    regs.charge_pump_output      = adf4360_regs_t::CHARGE_PUMP_OUTPUT_NORMAL;
    regs.cp_gain_0               = adf4360_regs_t::CP_GAIN_0_SET1;
    regs.mute_till_ld            = adf4360_regs_t::MUTE_TILL_LD_ENB;
    regs.output_power_level      = adf4360_regs_t::OUTPUT_POWER_LEVEL_3_5MA;
    regs.current_setting1        = adf4360_regs_t::CURRENT_SETTING1_0_31MA;
    regs.current_setting2        = adf4360_regs_t::CURRENT_SETTING2_0_31MA;
    regs.power_down              = adf4360_regs_t::POWER_DOWN_NORMAL_OP;
    regs.prescaler_value         = prescaler_to_enum[P];
    regs.a_counter               = A;
    regs.b_counter               = B;
    regs.cp_gain_1               = adf4360_regs_t::CP_GAIN_1_SET1;
    regs.divide_by_2_output      = (_div2[unit] && (!is_rx_rfx400)) ?  // Special case RFX400 RX Mixer divides by two
                                    adf4360_regs_t::DIVIDE_BY_2_OUTPUT_DIV2 :
                                    adf4360_regs_t::DIVIDE_BY_2_OUTPUT_FUND ;
    regs.divide_by_2_prescaler   = adf4360_regs_t::DIVIDE_BY_2_PRESCALER_FUND;
    regs.r_counter               = R;
    regs.ablpw                   = adf4360_regs_t::ABLPW_3_0NS;
    regs.lock_detect_precision   = adf4360_regs_t::LOCK_DETECT_PRECISION_5CYCLES;
    regs.test_mode_bit           = 0;
    regs.band_select_clock_div   = bandsel_to_enum[BS];

    //write the registers
    std::vector<adf4360_regs_t::addr_t> addrs = list_of //correct power-up sequence to write registers (R, C, N)
        (adf4360_regs_t::ADDR_RCOUNTER)
        (adf4360_regs_t::ADDR_CONTROL)
        (adf4360_regs_t::ADDR_NCOUNTER)
    ;
    BOOST_FOREACH(adf4360_regs_t::addr_t addr, addrs){
        this->get_iface()->write_spi(
            unit, spi_config_t::EDGE_RISE,
            regs.get_reg(addr), 24
        );
    }

    //return the actual frequency
    if (_div2[unit]) actual_freq /= 2;
    UHD_LOGV(often) << boost::format(
        "RFX tune: actual frequency %f MHz"
    ) % (actual_freq/1e6) << std::endl;
    return actual_freq;
}