X300: Change dboard clock rate to 50 MHz

4 files changed, 480 insertions, 345 deletions

diff --git a/host/lib/usrp/dboard/db_wbx_version4.cpp b/host/lib/usrp/dboard/db_wbx_version4.cpp
index f80aeda77..81cdaefac 100644
--- a/host/lib/usrp/dboard/db_wbx_version4.cpp
+++ b/host/lib/usrp/dboard/db_wbx_version4.cpp
@@ -63,7 +63,7 @@ static int tx_pga0_gain_to_iobits(double &gain){
             (attn_code &  8 ? 0 : TX_ATTN_8) |
             (attn_code &  4 ? 0 : TX_ATTN_4) |
             (attn_code &  2 ? 0 : TX_ATTN_2) |
-            (attn_code &  1 ? 0 : TX_ATTN_1) 
+            (attn_code &  1 ? 0 : TX_ATTN_1)
         ) & TX_ATTN_MASK;
 
     UHD_LOGV(often) << boost::format(
@@ -220,8 +220,8 @@ double wbx_base::wbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar
 
     //map prescaler setting to mininmum integer divider (N) values (pg.18 prescaler)
     static const uhd::dict<int, int> prescaler_to_min_int_div = map_list_of
-        (0,23) //adf4351_regs_t::PRESCALER_4_5
-        (1,75) //adf4351_regs_t::PRESCALER_8_9
+        (adf4351_regs_t::PRESCALER_4_5, 23)
+        (adf4351_regs_t::PRESCALER_8_9, 75)
     ;
 
     //map rf divider select output dividers to enums
@@ -237,14 +237,13 @@ double wbx_base::wbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar
 
     double reference_freq = self_base->get_iface()->get_clock_rate(unit);
     //The mixer has a divide-by-2 stage on the LO port so the synthesizer
-    //frequency must 2x the target frequency
+    //frequency must 2x the target frequency.  This introduces a 180 degree phase
+    //ambiguity when trying to synchronize the phase of multiple boards.
     double synth_target_freq = target_freq * 2;
-    //TODO: Document why the following has to be true
-    bool div_resync_enabled = (target_freq > reference_freq);
 
     adf4351_regs_t::prescaler_t prescaler =
-        synth_target_freq > 3e9 ? adf4351_regs_t::PRESCALER_8_9 : adf4351_regs_t::PRESCALER_4_5;
-    
+        synth_target_freq > 3.6e9 ? adf4351_regs_t::PRESCALER_8_9 : adf4351_regs_t::PRESCALER_4_5;
+
     adf435x_tuning_constraints tuning_constraints;
     tuning_constraints.force_frac0 = is_int_n;
     tuning_constraints.band_sel_freq_max = 100e3;
@@ -252,9 +251,13 @@ double wbx_base::wbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar
     tuning_constraints.int_range = uhd::range_t(prescaler_to_min_int_div[prescaler], 4095);
     tuning_constraints.pfd_freq_max = 25e6;
     tuning_constraints.rf_divider_range = uhd::range_t(1, 64);
-    //When divider resync is enabled, a 180 deg phase error is introduced when syncing
-    //multiple WBX boards. Switching to fundamental mode works arounds this issue.
-    tuning_constraints.feedback_after_divider = div_resync_enabled;
+    //The feedback of the divided frequency must be disabled whenever the target frequency
+    //divided by the minimum PFD frequency cannot meet the minimum integer divider (N) value.
+    //If it is disabled, additional phase ambiguity will be introduced.  With a minimum PFD
+    //frequency of 10 MHz, synthesizer frequencies below 230 MHz (LO frequencies below 115 MHz)
+    //will have too much ambiguity to synchronize.
+    tuning_constraints.feedback_after_divider =
+        (int(synth_target_freq / 10e6) >= prescaler_to_min_int_div[prescaler]);
 
     double synth_actual_freq = 0;
     adf435x_tuning_settings tuning_settings = tune_adf435x_synth(
@@ -281,7 +284,7 @@ double wbx_base::wbx_version4::set_lo_freq(dboard_iface::unit_t unit, double tar
     regs.feedback_select        = tuning_constraints.feedback_after_divider ?
                                     adf4351_regs_t::FEEDBACK_SELECT_DIVIDED :
                                     adf4351_regs_t::FEEDBACK_SELECT_FUNDAMENTAL;
-    regs.clock_div_mode         = div_resync_enabled ?
+    regs.clock_div_mode         = tuning_constraints.feedback_after_divider ?
                                     adf4351_regs_t::CLOCK_DIV_MODE_RESYNC_ENABLE :
                                     adf4351_regs_t::CLOCK_DIV_MODE_FAST_LOCK;
     regs.prescaler              = prescaler;
diff --git a/host/lib/usrp/x300/x300_clock_ctrl.cpp b/host/lib/usrp/x300/x300_clock_ctrl.cpp
index b59247d53..9bea4a4b4 100644
--- a/host/lib/usrp/x300/x300_clock_ctrl.cpp
+++ b/host/lib/usrp/x300/x300_clock_ctrl.cpp
@@ -25,6 +25,8 @@
 #include <cstdlib>
 
 static const double X300_REF_CLK_OUT_RATE  = 10e6;
+static const boost::uint16_t X300_MAX_CLKOUT_DIV = 1045;
+static const double X300_DEFAULT_DBOARD_CLK_RATE = 50e6;
 
 using namespace uhd;
 
@@ -36,370 +38,475 @@ class x300_clock_ctrl_impl : public x300_clock_ctrl    {
 
 public:
 
-~x300_clock_ctrl_impl(void) {}
-
-x300_clock_ctrl_impl(uhd::spi_iface::sptr spiface,
-    const size_t slaveno,
-    const size_t hw_rev,
-    const double master_clock_rate,
-    const double system_ref_rate):
-    _spiface(spiface),
-    _slaveno(slaveno),
-    _hw_rev(hw_rev),
-    _master_clock_rate(master_clock_rate),
-    _system_ref_rate(system_ref_rate)
-{
-}
-
-void reset_clocks() {
-    set_master_clock_rate(_master_clock_rate);
-}
-
-void sync_clocks(void) {
-    //soft sync:
-    //put the sync IO into output mode - FPGA must be input
-    //write low, then write high - this triggers a soft sync
-    _lmk04816_regs.SYNC_POL_INV = lmk04816_regs_t::SYNC_POL_INV_SYNC_LOW;
-    this->write_regs(11);
-    _lmk04816_regs.SYNC_POL_INV = lmk04816_regs_t::SYNC_POL_INV_SYNC_HIGH;
-    this->write_regs(11);
-}
-
-double get_master_clock_rate(void) {
-    return _master_clock_rate;
-}
-
-double get_sysref_clock_rate(void) {
-    return _system_ref_rate;
-}
+    ~x300_clock_ctrl_impl(void) {}
 
-double get_refout_clock_rate(void) {
-    //We support only one reference output rate
-    return X300_REF_CLK_OUT_RATE;
-}
-
-void set_dboard_rate(const x300_clock_which_t, double rate) {
-    if(not doubles_are_equal(rate, get_master_clock_rate())) {
-        throw uhd::not_implemented_error("x3xx set dboard clock rate does not support setting an arbitrary clock rate");
+    x300_clock_ctrl_impl(uhd::spi_iface::sptr spiface,
+        const size_t slaveno,
+        const size_t hw_rev,
+        const double master_clock_rate,
+        const double system_ref_rate):
+        _spiface(spiface),
+        _slaveno(slaveno),
+        _hw_rev(hw_rev),
+        _master_clock_rate(master_clock_rate),
+        _system_ref_rate(system_ref_rate)
+    {
+        init();
     }
-}
-
-std::vector<double> get_dboard_rates(const x300_clock_which_t) {
-    /* Right now, the only supported daughterboard clock rate is the master clock
-    * rate. TODO Implement divider settings for lower clock rates for legacy
-    * daughterboard support. */
-
-    std::vector<double> rates;
-    rates.push_back(get_master_clock_rate());
-    return rates;
-}
 
-void set_ref_out(const bool enable) {
-    // TODO  Implement divider configuration to allow for configurable output
-    // rates
-    if (enable)
-        _lmk04816_regs.CLKout10_TYPE = lmk04816_regs_t::CLKOUT10_TYPE_LVDS;
-    else
-        _lmk04816_regs.CLKout10_TYPE = lmk04816_regs_t::CLKOUT10_TYPE_P_DOWN;
-    this->write_regs(8);
-}
-
-void write_regs(boost::uint8_t addr) {
-    boost::uint32_t data = _lmk04816_regs.get_reg(addr);
-    _spiface->write_spi(_slaveno, spi_config_t::EDGE_RISE, data,32);
-}
-
-
-private:
-
-void set_master_clock_rate(double clock_rate) {
-    /* The X3xx has two primary rates. The first is the
-     * _system_ref_rate, which is sourced from the "clock_source"/"value" field
-     * of the property tree, and whose value can be 10e6, 30.72e6, or 200e6.
-     * The _system_ref_rate is the input to the clocking system, and
-     * what comes out is a disciplined master clock running at the
-     * _master_clock_rate. As such, only certain combinations of
-     * system reference rates and master clock rates are supported.
-     * Additionally, a subset of these will operate in "zero delay" mode. */
-
-    enum opmode_t { INVALID,
-                    m10M_200M_NOZDEL,      // used for debug purposes only
-                    m10M_200M_ZDEL,        // Normal mode
-                    m30_72M_184_32M_ZDEL,  // LTE with external ref, aka CPRI Mode
-                    m10M_184_32M_NOZDEL,   // LTE with 10 MHz ref
-                    m10M_120M_ZDEL };       // NI USRP 120 MHz Clocking
-
-    /* The default clocking mode is 10MHz reference generating a 200 MHz master
-     * clock, in zero-delay mode. */
-    opmode_t clocking_mode = INVALID;
-
-    if(doubles_are_equal(_system_ref_rate, 10e6)) {
-        if(doubles_are_equal(clock_rate, 184.32e6)) {
-            /* 10MHz reference, 184.32 MHz master clock out, NOT Zero Delay. */
-            clocking_mode = m10M_184_32M_NOZDEL;
-        } else if(doubles_are_equal(clock_rate, 200e6)) {
-            /* 10MHz reference, 200 MHz master clock out, Zero Delay */
-            clocking_mode = m10M_200M_ZDEL;
-        } else if(doubles_are_equal(clock_rate, 120e6)) {
-            /* 10MHz reference, 120 MHz master clock rate, Zero Delay */
-            clocking_mode = m10M_120M_ZDEL;
+    void reset_clocks() {
+        _lmk04816_regs.RESET = lmk04816_regs_t::RESET_RESET;
+        this->write_regs(0);
+        _lmk04816_regs.RESET = lmk04816_regs_t::RESET_NO_RESET;
+        for (size_t i = 0; i <= 16; ++i) {
+            this->write_regs(i);
         }
-    } else if(doubles_are_equal(_system_ref_rate, 30.72e6)) {
-        if(doubles_are_equal(clock_rate, 184.32e6)) {
-            /* 30.72MHz reference, 184.32 MHz master clock out, Zero Delay */
-            clocking_mode = m30_72M_184_32M_ZDEL;
+        for (size_t i = 24; i <= 31; ++i) {
+            this->write_regs(i);
         }
+        sync_clocks();
     }
 
-    if(clocking_mode == INVALID) {
-        throw uhd::runtime_error(str(boost::format("A master clock rate of %f cannot be derived from a system reference rate of %f") % clock_rate % _system_ref_rate));
+    void sync_clocks(void) {
+        //soft sync:
+        //put the sync IO into output mode - FPGA must be input
+        //write low, then write high - this triggers a soft sync
+        _lmk04816_regs.SYNC_POL_INV = lmk04816_regs_t::SYNC_POL_INV_SYNC_LOW;
+        this->write_regs(11);
+        _lmk04816_regs.SYNC_POL_INV = lmk04816_regs_t::SYNC_POL_INV_SYNC_HIGH;
+        this->write_regs(11);
     }
 
-    // For 200 MHz output, the VCO is run at 2400 MHz
-    // For the LTE/CPRI rate of 184.32 MHz, the VCO runs at 2580.48 MHz
-
-    int vco_div = 0;
-
-    // Note: PLL2 N2 prescaler is enabled for all cases
-    //       PLL2 reference doubler is enabled for all cases
-
-    /* All LMK04816 settings are from the LMK datasheet for our clocking
-     * architecture. Please refer to the datasheet for more information. */
-    switch (clocking_mode) {
-        case m10M_200M_NOZDEL:
-            vco_div = 12;
-            _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT;
+    double get_master_clock_rate(void) {
+        return _master_clock_rate;
+    }
 
-            // PLL1 - 2 MHz compare frequency
-            _lmk04816_regs.PLL1_N_28 = 48;
-            _lmk04816_regs.PLL1_R_27 = 5;
-            _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_100UA;
+    double get_sysref_clock_rate(void) {
+        return _system_ref_rate;
+    }
 
-            // PLL2 - 48 MHz compare frequency
-            _lmk04816_regs.PLL2_N_30 = 25;
-            _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_2A;
-            _lmk04816_regs.PLL2_R_28 = 4;
-            _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_3200UA;
+    double get_refout_clock_rate(void) {
+        //We support only one reference output rate
+        return X300_REF_CLK_OUT_RATE;
+    }
 
+    void set_dboard_rate(const x300_clock_which_t which, double rate) {
+        boost::uint16_t div = boost::uint16_t(_vco_freq / rate);
+        boost::uint16_t *reg = NULL;
+        boost::uint8_t addr = 0xFF;
+
+        // Make sure requested rate is an even divisor of the VCO frequency
+        if (not doubles_are_equal(_vco_freq / div, rate))
+            throw uhd::value_error("invalid dboard rate requested");
+
+        switch (which)
+        {
+        case X300_CLOCK_WHICH_DB0_RX:
+        case X300_CLOCK_WHICH_DB1_RX:
+            reg = &_lmk04816_regs.CLKout2_3_DIV;
+            addr = 1;
             break;
+        case X300_CLOCK_WHICH_DB0_TX:
+        case X300_CLOCK_WHICH_DB1_TX:
+            reg = &_lmk04816_regs.CLKout4_5_DIV;
+            addr = 2;
+            break;
+        default:
+            UHD_THROW_INVALID_CODE_PATH();
+        }
 
-        case m10M_200M_ZDEL:
-            vco_div = 12;
-            _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT_ZER_DELAY;
+        if (*reg == div)
+            return;
 
-            // PLL1 - 2 MHz compare frequency
-            _lmk04816_regs.PLL1_N_28 = 100;
-            _lmk04816_regs.PLL1_R_27 = 5;
-            _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_1600UA;
+        // Since the clock rate on one daughter board cannot be changed without
+        // affecting the other daughter board, don't allow it.
+        throw uhd::not_implemented_error("x3xx set dboard clock rate does not support changing the clock rate");
 
-            // PLL2 - 96 MHz compare frequency
-            _lmk04816_regs.PLL2_N_30 = 5;
-            _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_5;
-            _lmk04816_regs.PLL2_R_28 = 2;
+        // This is open source code and users may need to enable this function
+        // to support other daughterboards.  If so, comment out the line above
+        // that throws the error and allow the program to reach the code below.
 
-            if(_hw_rev <= 4)
-                _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_1600UA;
-            else
-                _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_400UA;
+        // The LMK04816 datasheet says the register must be written twice if SYNC is enabled
+        *reg = div;
+        write_regs(addr);
+        write_regs(addr);
+        sync_clocks();
+    }
 
+    double get_dboard_rate(const x300_clock_which_t which)
+    {
+        double rate = 0.0;
+        switch (which)
+        {
+        case X300_CLOCK_WHICH_DB0_RX:
+        case X300_CLOCK_WHICH_DB1_RX:
+            rate = _vco_freq / _lmk04816_regs.CLKout2_3_DIV;
             break;
+        case X300_CLOCK_WHICH_DB0_TX:
+        case X300_CLOCK_WHICH_DB1_TX:
+            rate = _vco_freq / _lmk04816_regs.CLKout4_5_DIV;
+            break;
+        default:
+            UHD_THROW_INVALID_CODE_PATH();
+        }
+        return rate;
+    }
 
-        case m30_72M_184_32M_ZDEL:
-            vco_div=14;
-            _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT_ZER_DELAY;
-
-            // PLL1 - 2.048 MHz compare frequency
-            _lmk04816_regs.PLL1_N_28 = 90;
-            _lmk04816_regs.PLL1_R_27 = 15;
-            _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_100UA;
+    std::vector<double> get_dboard_rates(const x300_clock_which_t)
+    {
+        std::vector<double> rates;
+        for (size_t div = size_t(_vco_freq / _master_clock_rate); div <= X300_MAX_CLKOUT_DIV; div++)
+            rates.push_back(_vco_freq / div);
+        return rates;
+    }
 
-            // PLL2 - 7.68 MHz compare frequency
-            _lmk04816_regs.PLL2_N_30 = 168;
-            _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_2A;
-            _lmk04816_regs.PLL2_R_28 = 25;
-            _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_3200UA;
+    void enable_dboard_clock(const x300_clock_which_t which, const bool enable)
+    {
+        switch (which)
+        {
+        case X300_CLOCK_WHICH_DB0_RX:
+            if (enable != (_lmk04816_regs.CLKout2_TYPE == lmk04816_regs_t::CLKOUT2_TYPE_LVPECL_700MVPP))
+            {
+                _lmk04816_regs.CLKout2_TYPE = enable ? lmk04816_regs_t::CLKOUT2_TYPE_LVPECL_700MVPP : lmk04816_regs_t::CLKOUT2_TYPE_P_DOWN;
+                write_regs(6);
+            }
+            break;
+        case X300_CLOCK_WHICH_DB1_RX:
+            if (enable != (_lmk04816_regs.CLKout3_TYPE == lmk04816_regs_t::CLKOUT3_TYPE_LVPECL_700MVPP))
+            {
+                _lmk04816_regs.CLKout3_TYPE = enable ? lmk04816_regs_t::CLKOUT3_TYPE_LVPECL_700MVPP : lmk04816_regs_t::CLKOUT3_TYPE_P_DOWN;
+                write_regs(6);
+            }
+            break;
+        case X300_CLOCK_WHICH_DB0_TX:
+            if (enable != (_lmk04816_regs.CLKout5_TYPE == lmk04816_regs_t::CLKOUT5_TYPE_LVPECL_700MVPP))
+            {
+                _lmk04816_regs.CLKout5_TYPE = enable ? lmk04816_regs_t::CLKOUT5_TYPE_LVPECL_700MVPP : lmk04816_regs_t::CLKOUT5_TYPE_P_DOWN;
+                write_regs(7);
+            }
+            break;
+        case X300_CLOCK_WHICH_DB1_TX:
+            if (enable != (_lmk04816_regs.CLKout4_TYPE == lmk04816_regs_t::CLKOUT4_TYPE_LVPECL_700MVPP))
+            {
+                _lmk04816_regs.CLKout4_TYPE = enable ? lmk04816_regs_t::CLKOUT4_TYPE_LVPECL_700MVPP : lmk04816_regs_t::CLKOUT4_TYPE_P_DOWN;
+                write_regs(7);
+            }
+            break;
+        default:
+            UHD_THROW_INVALID_CODE_PATH();
+        }
+    }
 
-            _lmk04816_regs.PLL2_R3_LF = lmk04816_regs_t::PLL2_R3_LF_1KILO_OHM;
-            _lmk04816_regs.PLL2_C3_LF = lmk04816_regs_t::PLL2_C3_LF_39PF;
+    void set_ref_out(const bool enable) {
+        // TODO  Implement divider configuration to allow for configurable output
+        // rates
+        if (enable)
+            _lmk04816_regs.CLKout10_TYPE = lmk04816_regs_t::CLKOUT10_TYPE_LVDS;
+        else
+            _lmk04816_regs.CLKout10_TYPE = lmk04816_regs_t::CLKOUT10_TYPE_P_DOWN;
+        this->write_regs(8);
+    }
 
-            _lmk04816_regs.PLL2_R4_LF = lmk04816_regs_t::PLL2_R4_LF_1KILO_OHM;
-            _lmk04816_regs.PLL2_C4_LF = lmk04816_regs_t::PLL2_C4_LF_34PF;
+    void write_regs(boost::uint8_t addr) {
+        boost::uint32_t data = _lmk04816_regs.get_reg(addr);
+        _spiface->write_spi(_slaveno, spi_config_t::EDGE_RISE, data,32);
+    }
 
-            break;
 
-        case m10M_184_32M_NOZDEL:
-            vco_div=14;
-            _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT;
+private:
 
-            // PLL1 - 2 MHz compare frequency
-            _lmk04816_regs.PLL1_N_28 = 48;
-            _lmk04816_regs.PLL1_R_27 = 5;
-            _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_100UA;
+    void init() {
+        /* The X3xx has two primary rates. The first is the
+         * _system_ref_rate, which is sourced from the "clock_source"/"value" field
+         * of the property tree, and whose value can be 10e6, 30.72e6, or 200e6.
+         * The _system_ref_rate is the input to the clocking system, and
+         * what comes out is a disciplined master clock running at the
+         * _master_clock_rate. As such, only certain combinations of
+         * system reference rates and master clock rates are supported.
+         * Additionally, a subset of these will operate in "zero delay" mode. */
+
+        enum opmode_t { INVALID,
+                        m10M_200M_NOZDEL,      // used for debug purposes only
+                        m10M_200M_ZDEL,        // Normal mode
+                        m30_72M_184_32M_ZDEL,  // LTE with external ref, aka CPRI Mode
+                        m10M_184_32M_NOZDEL,   // LTE with 10 MHz ref
+                        m10M_120M_ZDEL };       // NI USRP 120 MHz Clocking
+
+        /* The default clocking mode is 10MHz reference generating a 200 MHz master
+         * clock, in zero-delay mode. */
+        opmode_t clocking_mode = INVALID;
+
+        if(doubles_are_equal(_system_ref_rate, 10e6)) {
+            if(doubles_are_equal(_master_clock_rate, 184.32e6)) {
+                /* 10MHz reference, 184.32 MHz master clock out, NOT Zero Delay. */
+                clocking_mode = m10M_184_32M_NOZDEL;
+            } else if(doubles_are_equal(_master_clock_rate, 200e6)) {
+                /* 10MHz reference, 200 MHz master clock out, Zero Delay */
+                clocking_mode = m10M_200M_ZDEL;
+            } else if(doubles_are_equal(_master_clock_rate, 120e6)) {
+                /* 10MHz reference, 120 MHz master clock rate, Zero Delay */
+                clocking_mode = m10M_120M_ZDEL;
+            }
+        } else if(doubles_are_equal(_system_ref_rate, 30.72e6)) {
+            if(doubles_are_equal(_master_clock_rate, 184.32e6)) {
+                /* 30.72MHz reference, 184.32 MHz master clock out, Zero Delay */
+                clocking_mode = m30_72M_184_32M_ZDEL;
+            }
+        }
 
-            // PLL2 - 7.68 MHz compare frequency
-            _lmk04816_regs.PLL2_N_30 = 168;
-            _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_2A;
-            _lmk04816_regs.PLL2_R_28 = 25;
-            _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_3200UA;
+        if(clocking_mode == INVALID) {
+            throw uhd::runtime_error(str(boost::format("A master clock rate of %f cannot be derived from a system reference rate of %f") % _master_clock_rate % _system_ref_rate));
+        }
 
-            _lmk04816_regs.PLL2_R3_LF = lmk04816_regs_t::PLL2_R3_LF_4KILO_OHM;
-            _lmk04816_regs.PLL2_C3_LF = lmk04816_regs_t::PLL2_C3_LF_39PF;
+        // For 200 MHz output, the VCO is run at 2400 MHz
+        // For the LTE/CPRI rate of 184.32 MHz, the VCO runs at 2580.48 MHz
 
-            _lmk04816_regs.PLL2_R4_LF = lmk04816_regs_t::PLL2_R4_LF_1KILO_OHM;
-            _lmk04816_regs.PLL2_C4_LF = lmk04816_regs_t::PLL2_C4_LF_71PF;
+        // Note: PLL2 N2 prescaler is enabled for all cases
+        //       PLL2 reference doubler is enabled for all cases
 
-            break;
+        /* All LMK04816 settings are from the LMK datasheet for our clocking
+         * architecture. Please refer to the datasheet for more information. */
+        switch (clocking_mode) {
+            case m10M_200M_NOZDEL:
+                _vco_freq = 2400e6;
+                _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT;
 
-        case m10M_120M_ZDEL:
-            vco_div = 20;
-            _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT_ZER_DELAY;
+                // PLL1 - 2 MHz compare frequency
+                _lmk04816_regs.PLL1_N_28 = 48;
+                _lmk04816_regs.PLL1_R_27 = 5;
+                _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_100UA;
 
-            // PLL1 - 2 MHz compare frequency
-            _lmk04816_regs.PLL1_N_28 = 60;
-            _lmk04816_regs.PLL1_R_27 = 5;
-            _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_100UA;
+                // PLL2 - 48 MHz compare frequency
+                _lmk04816_regs.PLL2_N_30 = 25;
+                _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_2A;
+                _lmk04816_regs.PLL2_R_28 = 4;
+                _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_3200UA;
 
-            // PLL2 - 96 MHz compare frequency
-            _lmk04816_regs.PLL2_N_30 = 5;
-            _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_5;
-            _lmk04816_regs.PLL2_R_28 = 2;
+                break;
 
-            if(_hw_rev <= 4)
-                _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_1600UA;
-            else
-                _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_400UA;
+            case m10M_200M_ZDEL:
+                _vco_freq = 2400e6;
+                _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT_ZER_DELAY;
 
-            break;
+                // PLL1 - 2 MHz compare frequency
+                _lmk04816_regs.PLL1_N_28 = 5;
+                _lmk04816_regs.PLL1_R_27 = 5;
+                _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_1600UA;
+
+                // PLL2 - 96 MHz compare frequency
+                _lmk04816_regs.PLL2_N_30 = 5;
+                _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_5;
+                _lmk04816_regs.PLL2_R_28 = 2;
+
+                if(_hw_rev <= 4)
+                    _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_1600UA;
+                else
+                    _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_400UA;
+
+                break;
+
+            case m30_72M_184_32M_ZDEL:
+                _vco_freq = 2580.48e6;
+                _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT_ZER_DELAY;
+
+                // PLL1 - 2.048 MHz compare frequency
+                _lmk04816_regs.PLL1_N_28 = 15;
+                _lmk04816_regs.PLL1_R_27 = 15;
+                _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_100UA;
+
+                // PLL2 - 7.68 MHz compare frequency
+                _lmk04816_regs.PLL2_N_30 = 168;
+                _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_2A;
+                _lmk04816_regs.PLL2_R_28 = 25;
+                _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_3200UA;
+
+                _lmk04816_regs.PLL2_R3_LF = lmk04816_regs_t::PLL2_R3_LF_1KILO_OHM;
+                _lmk04816_regs.PLL2_C3_LF = lmk04816_regs_t::PLL2_C3_LF_39PF;
+
+                _lmk04816_regs.PLL2_R4_LF = lmk04816_regs_t::PLL2_R4_LF_1KILO_OHM;
+                _lmk04816_regs.PLL2_C4_LF = lmk04816_regs_t::PLL2_C4_LF_34PF;
+
+                break;
+
+            case m10M_184_32M_NOZDEL:
+                _vco_freq = 2580.48e6;
+                _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT;
+
+                // PLL1 - 2 MHz compare frequency
+                _lmk04816_regs.PLL1_N_28 = 48;
+                _lmk04816_regs.PLL1_R_27 = 5;
+                _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_100UA;
+
+                // PLL2 - 7.68 MHz compare frequency
+                _lmk04816_regs.PLL2_N_30 = 168;
+                _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_2A;
+                _lmk04816_regs.PLL2_R_28 = 25;
+                _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_3200UA;
+
+                _lmk04816_regs.PLL2_R3_LF = lmk04816_regs_t::PLL2_R3_LF_4KILO_OHM;
+                _lmk04816_regs.PLL2_C3_LF = lmk04816_regs_t::PLL2_C3_LF_39PF;
+
+                _lmk04816_regs.PLL2_R4_LF = lmk04816_regs_t::PLL2_R4_LF_1KILO_OHM;
+                _lmk04816_regs.PLL2_C4_LF = lmk04816_regs_t::PLL2_C4_LF_71PF;
+
+                break;
+
+            case m10M_120M_ZDEL:
+                _vco_freq = 2400e6;
+                _lmk04816_regs.MODE = lmk04816_regs_t::MODE_DUAL_INT_ZER_DELAY;
+
+                // PLL1 - 2 MHz compare frequency
+                _lmk04816_regs.PLL1_N_28 = 5;
+                _lmk04816_regs.PLL1_R_27 = 5;
+                _lmk04816_regs.PLL1_CP_GAIN_27 = lmk04816_regs_t::PLL1_CP_GAIN_27_100UA;
+
+                // PLL2 - 96 MHz compare frequency
+                _lmk04816_regs.PLL2_N_30 = 5;
+                _lmk04816_regs.PLL2_P_30 = lmk04816_regs_t::PLL2_P_30_DIV_5;
+                _lmk04816_regs.PLL2_R_28 = 2;
+
+                if(_hw_rev <= 4)
+                    _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_1600UA;
+                else
+                    _lmk04816_regs.PLL2_CP_GAIN_26 = lmk04816_regs_t::PLL2_CP_GAIN_26_400UA;
+
+                break;
+
+            default:
+                UHD_THROW_INVALID_CODE_PATH();
+                break;
+        };
+
+        boost::uint16_t master_clock_div = static_cast<boost::uint16_t>(
+            std::ceil(_vco_freq / _master_clock_rate));
+
+        boost::uint16_t dboard_div = static_cast<boost::uint16_t>(
+            std::ceil(_vco_freq / X300_DEFAULT_DBOARD_CLK_RATE));
+
+        /* Reset the LMK clock controller. */
+        _lmk04816_regs.RESET = lmk04816_regs_t::RESET_RESET;
+        this->write_regs(0);
+        _lmk04816_regs.RESET = lmk04816_regs_t::RESET_NO_RESET;
+        this->write_regs(0);
+
+        /* Initial power-up */
+        _lmk04816_regs.CLKout0_1_PD = lmk04816_regs_t::CLKOUT0_1_PD_POWER_UP;
+        this->write_regs(0);
+        _lmk04816_regs.CLKout0_1_DIV = master_clock_div;
+        _lmk04816_regs.CLKout0_ADLY_SEL = lmk04816_regs_t::CLKOUT0_ADLY_SEL_D_EV_X;
+        this->write_regs(0);
+
+        // Register 1
+        _lmk04816_regs.CLKout2_3_PD = lmk04816_regs_t::CLKOUT2_3_PD_POWER_UP;
+        _lmk04816_regs.CLKout2_3_DIV = dboard_div;
+        // Register 2
+        _lmk04816_regs.CLKout4_5_PD = lmk04816_regs_t::CLKOUT4_5_PD_POWER_UP;
+        _lmk04816_regs.CLKout4_5_DIV = dboard_div;
+        // Register 3
+        _lmk04816_regs.CLKout6_7_DIV = master_clock_div;
+        _lmk04816_regs.CLKout6_7_OSCin_Sel = lmk04816_regs_t::CLKOUT6_7_OSCIN_SEL_VCO;
+        // Register 4
+        _lmk04816_regs.CLKout8_9_DIV = master_clock_div;
+        // Register 5
+        _lmk04816_regs.CLKout10_11_PD = lmk04816_regs_t::CLKOUT10_11_PD_NORMAL;
+        _lmk04816_regs.CLKout10_11_DIV =
+            static_cast<boost::uint16_t>(std::ceil(_vco_freq / _system_ref_rate));
+
+        // Register 6
+        _lmk04816_regs.CLKout0_TYPE = lmk04816_regs_t::CLKOUT0_TYPE_LVDS; //FPGA
+        _lmk04816_regs.CLKout1_TYPE = lmk04816_regs_t::CLKOUT1_TYPE_P_DOWN; //CPRI feedback clock, use LVDS
+        _lmk04816_regs.CLKout2_TYPE = lmk04816_regs_t::CLKOUT2_TYPE_LVPECL_700MVPP; //DB_0_RX
+        _lmk04816_regs.CLKout3_TYPE = lmk04816_regs_t::CLKOUT3_TYPE_LVPECL_700MVPP; //DB_1_RX
+        // Analog delay of 900ps to synchronize the radio clock with the source synchronous ADC clocks.
+        // This delay may need to vary due to temperature.  Tested and verified at room temperature only.
+        _lmk04816_regs.CLKout0_1_ADLY = 0x10;
+
+        // Register 7
+        _lmk04816_regs.CLKout4_TYPE = lmk04816_regs_t::CLKOUT4_TYPE_LVPECL_700MVPP; //DB_1_TX
+        _lmk04816_regs.CLKout5_TYPE = lmk04816_regs_t::CLKOUT5_TYPE_LVPECL_700MVPP; //DB_0_TX
+        _lmk04816_regs.CLKout6_TYPE = lmk04816_regs_t::CLKOUT6_TYPE_LVPECL_700MVPP; //DB0_DAC
+        _lmk04816_regs.CLKout7_TYPE = lmk04816_regs_t::CLKOUT7_TYPE_LVPECL_700MVPP; //DB1_DAC
+        _lmk04816_regs.CLKout8_TYPE = lmk04816_regs_t::CLKOUT8_TYPE_LVPECL_700MVPP; //DB0_ADC
+
+        // Register 8
+        _lmk04816_regs.CLKout9_TYPE = lmk04816_regs_t::CLKOUT9_TYPE_LVPECL_700MVPP; //DB1_ADC
+        _lmk04816_regs.CLKout10_TYPE = lmk04816_regs_t::CLKOUT10_TYPE_LVDS; //REF_CLKOUT
+        _lmk04816_regs.CLKout11_TYPE = lmk04816_regs_t::CLKOUT11_TYPE_P_DOWN; //Debug header, use LVPECL
+
+
+        // Register 10
+        _lmk04816_regs.EN_OSCout0 = lmk04816_regs_t::EN_OSCOUT0_DISABLED; //Debug header
+        _lmk04816_regs.FEEDBACK_MUX = 5; //use output 10 (REF OUT) for feedback
+        _lmk04816_regs.EN_FEEDBACK_MUX = lmk04816_regs_t::EN_FEEDBACK_MUX_ENABLED;
+
+        // Register 11
+        // MODE set in individual cases above
+        _lmk04816_regs.SYNC_QUAL = lmk04816_regs_t::SYNC_QUAL_FB_MUX;
+        _lmk04816_regs.EN_SYNC = lmk04816_regs_t::EN_SYNC_ENABLE;
+        _lmk04816_regs.NO_SYNC_CLKout0_1 = lmk04816_regs_t::NO_SYNC_CLKOUT0_1_CLOCK_XY_SYNC;
+        _lmk04816_regs.NO_SYNC_CLKout2_3 = lmk04816_regs_t::NO_SYNC_CLKOUT2_3_CLOCK_XY_SYNC;
+        _lmk04816_regs.NO_SYNC_CLKout4_5 = lmk04816_regs_t::NO_SYNC_CLKOUT4_5_CLOCK_XY_SYNC;
+        _lmk04816_regs.NO_SYNC_CLKout6_7 = lmk04816_regs_t::NO_SYNC_CLKOUT6_7_CLOCK_XY_SYNC;
+        _lmk04816_regs.NO_SYNC_CLKout8_9 = lmk04816_regs_t::NO_SYNC_CLKOUT8_9_CLOCK_XY_SYNC;
+        _lmk04816_regs.NO_SYNC_CLKout10_11 = lmk04816_regs_t::NO_SYNC_CLKOUT10_11_CLOCK_XY_SYNC;
+        _lmk04816_regs.SYNC_TYPE = lmk04816_regs_t::SYNC_TYPE_INPUT;
+
+        // Register 12
+        _lmk04816_regs.LD_MUX = lmk04816_regs_t::LD_MUX_BOTH;
+
+        /* Input Clock Configurations */
+        // Register 13
+        _lmk04816_regs.EN_CLKin0 = lmk04816_regs_t::EN_CLKIN0_NO_VALID_USE;  // This is not connected
+        _lmk04816_regs.EN_CLKin2 = lmk04816_regs_t::EN_CLKIN2_NO_VALID_USE;  // Used only for CPRI
+        _lmk04816_regs.Status_CLKin1_MUX = lmk04816_regs_t::STATUS_CLKIN1_MUX_UWIRE_RB;
+        _lmk04816_regs.CLKin_Select_MODE = lmk04816_regs_t::CLKIN_SELECT_MODE_CLKIN1_MAN;
+        _lmk04816_regs.HOLDOVER_MUX = lmk04816_regs_t::HOLDOVER_MUX_PLL1_R;
+        // Register 14
+        _lmk04816_regs.Status_CLKin1_TYPE = lmk04816_regs_t::STATUS_CLKIN1_TYPE_OUT_PUSH_PULL;
+        _lmk04816_regs.Status_CLKin0_TYPE = lmk04816_regs_t::STATUS_CLKIN0_TYPE_OUT_PUSH_PULL;
+
+        // Register 26
+        // PLL2_CP_GAIN_26 set above in individual cases
+        _lmk04816_regs.PLL2_CP_POL_26 = lmk04816_regs_t::PLL2_CP_POL_26_NEG_SLOPE;
+        _lmk04816_regs.EN_PLL2_REF_2X = lmk04816_regs_t::EN_PLL2_REF_2X_DOUBLED_FREQ_REF;
+
+        // Register 27
+        // PLL1_CP_GAIN_27 set in individual cases above
+        // PLL1_R_27 set in the individual cases above
+
+        // Register 28
+        // PLL1_N_28 and PLL2_R_28 are set in the individual cases above
+
+        // Register 29
+        _lmk04816_regs.PLL2_N_CAL_29 = _lmk04816_regs.PLL2_N_30;  // N_CAL should always match N
+        _lmk04816_regs.OSCin_FREQ_29 = lmk04816_regs_t::OSCIN_FREQ_29_63_TO_127MHZ;
+
+        // Register 30
+        // PLL2_P_30 set in individual cases above
+        // PLL2_N_30 set in individual cases above
+
+        /* Write the configuration values into the LMK */
+        for (size_t i = 1; i <= 16; ++i) {
+            this->write_regs(i);
+        }
+        for (size_t i = 24; i <= 31; ++i) {
+            this->write_regs(i);
+        }
 
-        default:
-            UHD_THROW_INVALID_CODE_PATH();
-            break;
-    };
-
-    /* Reset the LMK clock controller. */
-    _lmk04816_regs.RESET = lmk04816_regs_t::RESET_RESET;
-    this->write_regs(0);
-    _lmk04816_regs.RESET = lmk04816_regs_t::RESET_NO_RESET;
-    this->write_regs(0);
-
-    /* Initial power-up */
-    _lmk04816_regs.CLKout0_1_PD = lmk04816_regs_t::CLKOUT0_1_PD_POWER_UP;
-    this->write_regs(0);
-    _lmk04816_regs.CLKout0_1_DIV = vco_div;
-    _lmk04816_regs.CLKout0_ADLY_SEL = lmk04816_regs_t::CLKOUT0_ADLY_SEL_D_EV_X;
-    this->write_regs(0);
-
-    // Register 1
-    _lmk04816_regs.CLKout2_3_PD = lmk04816_regs_t::CLKOUT2_3_PD_POWER_UP;
-    _lmk04816_regs.CLKout2_3_DIV = vco_div;
-    // Register 2
-    _lmk04816_regs.CLKout4_5_PD = lmk04816_regs_t::CLKOUT4_5_PD_POWER_UP;
-    _lmk04816_regs.CLKout4_5_DIV = vco_div;
-    // Register 3
-    _lmk04816_regs.CLKout6_7_DIV = vco_div;
-    _lmk04816_regs.CLKout6_7_OSCin_Sel = lmk04816_regs_t::CLKOUT6_7_OSCIN_SEL_VCO;
-    // Register 4
-    _lmk04816_regs.CLKout8_9_DIV = vco_div;
-    // Register 5
-    _lmk04816_regs.CLKout10_11_PD = lmk04816_regs_t::CLKOUT10_11_PD_NORMAL;
-    _lmk04816_regs.CLKout10_11_DIV = vco_div * static_cast<int>(clock_rate/X300_REF_CLK_OUT_RATE);
-
-    // Register 6
-    _lmk04816_regs.CLKout0_TYPE = lmk04816_regs_t::CLKOUT0_TYPE_LVDS; //FPGA
-    _lmk04816_regs.CLKout1_TYPE = lmk04816_regs_t::CLKOUT1_TYPE_P_DOWN; //CPRI feedback clock, use LVDS
-    _lmk04816_regs.CLKout2_TYPE = lmk04816_regs_t::CLKOUT2_TYPE_LVPECL_700MVPP; //DB_0_RX
-    _lmk04816_regs.CLKout3_TYPE = lmk04816_regs_t::CLKOUT3_TYPE_LVPECL_700MVPP; //DB_1_RX
-    // Analog delay of 900ps to synchronize the radio clock with the source synchronous ADC clocks.
-    // This delay may need to vary due to temperature.  Tested and verified at room temperature only.
-    _lmk04816_regs.CLKout0_1_ADLY = 0x10;
-
-    // Register 7
-    _lmk04816_regs.CLKout4_TYPE = lmk04816_regs_t::CLKOUT4_TYPE_LVPECL_700MVPP; //DB_1_TX
-    _lmk04816_regs.CLKout5_TYPE = lmk04816_regs_t::CLKOUT5_TYPE_LVPECL_700MVPP; //DB_0_TX
-    _lmk04816_regs.CLKout6_TYPE = lmk04816_regs_t::CLKOUT6_TYPE_LVPECL_700MVPP; //DB0_DAC
-    _lmk04816_regs.CLKout7_TYPE = lmk04816_regs_t::CLKOUT7_TYPE_LVPECL_700MVPP; //DB1_DAC
-    _lmk04816_regs.CLKout8_TYPE = lmk04816_regs_t::CLKOUT8_TYPE_LVPECL_700MVPP; //DB0_ADC
-
-    // Register 8
-    _lmk04816_regs.CLKout9_TYPE = lmk04816_regs_t::CLKOUT9_TYPE_LVPECL_700MVPP; //DB1_ADC
-    _lmk04816_regs.CLKout10_TYPE = lmk04816_regs_t::CLKOUT10_TYPE_LVDS; //REF_CLKOUT
-    _lmk04816_regs.CLKout11_TYPE = lmk04816_regs_t::CLKOUT11_TYPE_P_DOWN; //Debug header, use LVPECL
-
-
-    // Register 10
-    _lmk04816_regs.EN_OSCout0 = lmk04816_regs_t::EN_OSCOUT0_DISABLED; //Debug header
-    _lmk04816_regs.FEEDBACK_MUX = 0; //use output 0 (FPGA clock) for feedback
-    _lmk04816_regs.EN_FEEDBACK_MUX = lmk04816_regs_t::EN_FEEDBACK_MUX_ENABLED;
-
-    // Register 11
-    // MODE set in individual cases above
-    _lmk04816_regs.SYNC_QUAL = lmk04816_regs_t::SYNC_QUAL_FB_MUX;
-    _lmk04816_regs.EN_SYNC = lmk04816_regs_t::EN_SYNC_ENABLE;
-    _lmk04816_regs.NO_SYNC_CLKout0_1 = lmk04816_regs_t::NO_SYNC_CLKOUT0_1_CLOCK_XY_SYNC;
-    _lmk04816_regs.NO_SYNC_CLKout2_3 = lmk04816_regs_t::NO_SYNC_CLKOUT2_3_CLOCK_XY_SYNC;
-    _lmk04816_regs.NO_SYNC_CLKout4_5 = lmk04816_regs_t::NO_SYNC_CLKOUT4_5_CLOCK_XY_SYNC;
-    _lmk04816_regs.NO_SYNC_CLKout6_7 = lmk04816_regs_t::NO_SYNC_CLKOUT6_7_CLOCK_XY_SYNC;
-    _lmk04816_regs.NO_SYNC_CLKout8_9 = lmk04816_regs_t::NO_SYNC_CLKOUT8_9_CLOCK_XY_SYNC;
-    _lmk04816_regs.NO_SYNC_CLKout10_11 = lmk04816_regs_t::NO_SYNC_CLKOUT10_11_CLOCK_XY_SYNC;
-    _lmk04816_regs.SYNC_EN_AUTO = lmk04816_regs_t::SYNC_EN_AUTO_SYNC_INT_GEN;
-    _lmk04816_regs.SYNC_POL_INV = lmk04816_regs_t::SYNC_POL_INV_SYNC_LOW;
-    _lmk04816_regs.SYNC_TYPE = lmk04816_regs_t::SYNC_TYPE_INPUT;
-
-    // Register 12
-    _lmk04816_regs.LD_MUX = lmk04816_regs_t::LD_MUX_BOTH;
-
-    /* Input Clock Configurations */
-    // Register 13
-    _lmk04816_regs.EN_CLKin0 = lmk04816_regs_t::EN_CLKIN0_NO_VALID_USE;  // This is not connected
-    _lmk04816_regs.EN_CLKin2 = lmk04816_regs_t::EN_CLKIN2_NO_VALID_USE;  // Used only for CPRI
-    _lmk04816_regs.Status_CLKin1_MUX = lmk04816_regs_t::STATUS_CLKIN1_MUX_UWIRE_RB;
-    _lmk04816_regs.CLKin_Select_MODE = lmk04816_regs_t::CLKIN_SELECT_MODE_CLKIN1_MAN;
-    _lmk04816_regs.HOLDOVER_MUX = lmk04816_regs_t::HOLDOVER_MUX_PLL1_R;
-    // Register 14
-    _lmk04816_regs.Status_CLKin1_TYPE = lmk04816_regs_t::STATUS_CLKIN1_TYPE_OUT_PUSH_PULL;
-    _lmk04816_regs.Status_CLKin0_TYPE = lmk04816_regs_t::STATUS_CLKIN0_TYPE_OUT_PUSH_PULL;
-
-    // Register 26
-    // PLL2_CP_GAIN_26 set above in individual cases
-    _lmk04816_regs.PLL2_CP_POL_26 = lmk04816_regs_t::PLL2_CP_POL_26_NEG_SLOPE;
-    _lmk04816_regs.EN_PLL2_REF_2X = lmk04816_regs_t::EN_PLL2_REF_2X_DOUBLED_FREQ_REF;
-
-    // Register 27
-    // PLL1_CP_GAIN_27 set in individual cases above
-    // PLL1_R_27 set in the individual cases above
-
-    // Register 28
-    // PLL1_N_28 and PLL2_R_28 are set in the individual cases above
-
-    // Register 29
-    _lmk04816_regs.PLL2_N_CAL_29 = _lmk04816_regs.PLL2_N_30;  // N_CAL should always match N
-    _lmk04816_regs.OSCin_FREQ_29 = lmk04816_regs_t::OSCIN_FREQ_29_63_TO_127MHZ;
-
-    // Register 30
-    // PLL2_P_30 set in individual cases above
-    // PLL2_N_30 set in individual cases above
-
-    /* Write the configuration values into the LMK */
-    for (size_t i = 1; i <= 16; ++i) {
-        this->write_regs(i);
-    }
-    for (size_t i = 24; i <= 31; ++i) {
-        this->write_regs(i);
+        this->sync_clocks();
     }
 
-    this->sync_clocks();
-}
-
-UHD_INLINE bool doubles_are_equal(double a, double b) {
-    return  (std::fabs(a - b) < std::numeric_limits<double>::epsilon());
-}
+    UHD_INLINE bool doubles_are_equal(double a, double b) {
+        return  (std::fabs(a - b) < std::numeric_limits<double>::epsilon());
+    }
 
-const spi_iface::sptr _spiface;
-const size_t _slaveno;
-const size_t _hw_rev;
-const double _master_clock_rate;
-const double _system_ref_rate;
-lmk04816_regs_t _lmk04816_regs;
+    const spi_iface::sptr _spiface;
+    const size_t _slaveno;
+    const size_t _hw_rev;
+    const double _master_clock_rate;
+    const double _system_ref_rate;
+    lmk04816_regs_t _lmk04816_regs;
+    double _vco_freq;
 };
 
 x300_clock_ctrl::sptr x300_clock_ctrl::make(uhd::spi_iface::sptr spiface,
diff --git a/host/lib/usrp/x300/x300_clock_ctrl.hpp b/host/lib/usrp/x300/x300_clock_ctrl.hpp
index 40b62b09a..9c08aa356 100644
--- a/host/lib/usrp/x300/x300_clock_ctrl.hpp
+++ b/host/lib/usrp/x300/x300_clock_ctrl.hpp
@@ -71,11 +71,24 @@ public:
      */
     virtual void set_dboard_rate(const x300_clock_which_t which, double rate) = 0;
 
+    /*! Get the clock rate on the given daughterboard clock.
+     * \throw exception when rate invalid
+     * \return the clock rate in Hz
+     */
+    virtual double get_dboard_rate(const x300_clock_which_t which) = 0;
+
     /*! Get a list of possible daughterboard clock rates.
      * \return a list of clock rates in Hz
      */
     virtual std::vector<double> get_dboard_rates(const x300_clock_which_t which) = 0;
 
+    /*! Enable or disable daughterboard clock.
+     * \param which which clock
+     * \param enable true=enable, false=disable
+     * \return a list of clock rates in Hz
+     */
+    virtual void enable_dboard_clock(const x300_clock_which_t which, const bool enable) = 0;
+
     /*! Turn the reference output on/off
      * \param true = on, false = off
      */
diff --git a/host/lib/usrp/x300/x300_dboard_iface.cpp b/host/lib/usrp/x300/x300_dboard_iface.cpp
index c286e805a..502630109 100644
--- a/host/lib/usrp/x300/x300_dboard_iface.cpp
+++ b/host/lib/usrp/x300/x300_dboard_iface.cpp
@@ -111,12 +111,12 @@ x300_dboard_iface::x300_dboard_iface(const x300_dboard_iface_config_t &config):
         this->_write_aux_dac(unit);
     }
 
+    _clock_rates[UNIT_RX] = _config.clock->get_dboard_rate(_config.which_rx_clk);
+    _clock_rates[UNIT_TX] = _config.clock->get_dboard_rate(_config.which_tx_clk);
+
     this->set_clock_enabled(UNIT_RX, false);
     this->set_clock_enabled(UNIT_TX, false);
 
-    this->set_clock_rate(UNIT_RX, _config.clock->get_master_clock_rate());
-    this->set_clock_rate(UNIT_TX, _config.clock->get_master_clock_rate());
-
 
     //some test code
     /*
@@ -153,16 +153,20 @@ x300_dboard_iface::~x300_dboard_iface(void)
  **********************************************************************/
 void x300_dboard_iface::set_clock_rate(unit_t unit, double rate)
 {
-    _clock_rates[unit] = rate; //set to shadow
+    // Just return if the requested rate is already set
+    if (std::fabs(_clock_rates[unit] - rate) < std::numeric_limits<double>::epsilon())
+        return;
+
     switch(unit)
     {
         case UNIT_RX:
             _config.clock->set_dboard_rate(_config.which_rx_clk, rate);
-            return;
+            break;
         case UNIT_TX:
             _config.clock->set_dboard_rate(_config.which_tx_clk, rate);
-            return;
+            break;
     }
+    _clock_rates[unit] = rate; //set to shadow
 }
 
 double x300_dboard_iface::get_clock_rate(unit_t unit)
@@ -183,9 +187,17 @@ std::vector<double> x300_dboard_iface::get_clock_rates(unit_t unit)
     }
 }
 
-void x300_dboard_iface::set_clock_enabled(UHD_UNUSED(unit_t unit), UHD_UNUSED(bool enb))
+void x300_dboard_iface::set_clock_enabled(unit_t unit, bool enb)
 {
-    // TODO Variable DBoard clock control needs to be implemented for X300.
+    switch(unit)
+    {
+        case UNIT_RX:
+            return _config.clock->enable_dboard_clock(_config.which_rx_clk, enb);
+        case UNIT_TX:
+            return _config.clock->enable_dboard_clock(_config.which_tx_clk, enb);
+        default:
+            UHD_THROW_INVALID_CODE_PATH();
+    }
 }
 
 double x300_dboard_iface::get_codec_rate(unit_t)