1 files changed, 156 insertions, 0 deletions
diff --git a/host/lib/usrp/common/adf435x_common.cpp b/host/lib/usrp/common/adf435x_common.cpp
new file mode 100644
index 000000000..e9d018fec
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+++ b/host/lib/usrp/common/adf435x_common.cpp
@@ -0,0 +1,156 @@
+//
+// Copyright 2013-2014 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/>.
+//
+
+#include "adf435x_common.hpp"
+#include <uhd/types/tune_request.hpp>
+#include <uhd/utils/log.hpp>
+
+using namespace uhd;
+
+/***********************************************************************
+ * ADF 4350/4351 Tuning Utility
+ **********************************************************************/
+adf435x_tuning_settings tune_adf435x_synth(
+    double target_freq,
+    double ref_freq,
+    const adf435x_tuning_constraints& constraints,
+    double& actual_freq)
+{
+    //Default invalid value for actual_freq
+    actual_freq = 0;
+
+    double pfd_freq = 0;
+    boost::uint16_t R = 0, BS = 0, N = 0, FRAC = 0, MOD = 0;
+    boost::uint16_t RFdiv = static_cast<boost::uint16_t>(constraints.rf_divider_range.start());
+    bool D = false, T = false;
+
+    //Reference doubler for 50% duty cycle
+    //If ref_freq < 12.5MHz enable the reference doubler
+    D = (ref_freq <= constraints.ref_doubler_threshold);
+
+    static const double MIN_VCO_FREQ = 2.2e9;
+    static const double MAX_VCO_FREQ = 4.4e9;
+
+    //increase RF divider until acceptable VCO frequency
+    double vco_freq = target_freq;
+    while (vco_freq < MIN_VCO_FREQ && RFdiv < static_cast<boost::uint16_t>(constraints.rf_divider_range.stop())) {
+        vco_freq *= 2;
+        RFdiv *= 2;
+    }
+
+    /*
+     * The goal here is to loop though possible R dividers,
+     * band select clock dividers, N (int) dividers, and FRAC
+     * (frac) dividers.
+     *
+     * Calculate the N and F dividers for each set of values.
+     * The loop exits when it meets all of the constraints.
+     * The resulting loop values are loaded into the registers.
+     *
+     * from pg.21
+     *
+     * f_pfd = f_ref*(1+D)/(R*(1+T))
+     * f_vco = (N + (FRAC/MOD))*f_pfd
+     *    N = f_vco/f_pfd - FRAC/MOD = f_vco*((R*(T+1))/(f_ref*(1+D))) - FRAC/MOD
+     * f_rf = f_vco/RFdiv)
+     * f_actual = f_rf/2
+     */
+    for(R = 1; R <= 1023; R+=1){
+        //PFD input frequency = f_ref/R ... ignoring Reference doubler/divide-by-2 (D & T)
+        pfd_freq = ref_freq*(D?2:1)/(R*(T?2:1));
+
+        //keep the PFD frequency at or below 25MHz (Loop Filter Bandwidth)
+        if (pfd_freq > constraints.pfd_freq_max) continue;
+
+        //ignore fractional part of tuning
+        //N is computed from target_freq and not vco_freq because the feedback
+        //mode is set to FEEDBACK_SELECT_DIVIDED
+        N = boost::uint16_t(std::floor(target_freq/pfd_freq));
+
+        //keep N > minimum int divider requirement
+        if (N < static_cast<boost::uint16_t>(constraints.int_range.start())) continue;
+
+        for(BS=1; BS <= 255; BS+=1){
+            //keep the band select frequency at or below band_sel_freq_max
+            //constraint on band select clock
+            if (pfd_freq/BS > constraints.band_sel_freq_max) continue;
+            goto done_loop;
+        }
+    } done_loop:
+
+    //Fractional-N calculation
+    MOD = 4095; //max fractional accuracy
+    //N is computed from target_freq and not vco_freq because the feedback
+    //mode is set to FEEDBACK_SELECT_DIVIDED
+    FRAC = static_cast<boost::uint16_t>((target_freq/pfd_freq - N)*MOD);
+    if (constraints.force_frac0) {
+        if (FRAC > (MOD / 2)) { //Round integer such that actual freq is closest to target
+            N++;
+        }
+        FRAC = 0;
+    }
+
+    //Reference divide-by-2 for 50% duty cycle
+    // if R even, move one divide by 2 to to regs.reference_divide_by_2
+    if(R % 2 == 0) {
+        T = true;
+        R /= 2;
+    }
+
+    //Typical phase resync time documented in data sheet pg.24
+    static const double PHASE_RESYNC_TIME = 400e-6;
+
+    //actual frequency calculation
+    actual_freq = double((N + (double(FRAC)/double(MOD)))*ref_freq*(D?2:1)/(R*(T?2:1)));
+
+    //load the settings
+    adf435x_tuning_settings settings;
+    settings.frac_12_bit = FRAC;
+    settings.int_16_bit = N;
+    settings.mod_12_bit = MOD;
+    settings.clock_divider_12_bit = std::max<boost::uint16_t>(1, std::ceil(PHASE_RESYNC_TIME*pfd_freq/MOD));
+    settings.r_counter_10_bit = R;
+    settings.r_divide_by_2_en = T;
+    settings.r_doubler_en = D;
+    settings.band_select_clock_div = BS;
+    settings.rf_divider = RFdiv;
+    settings.feedback_after_divider = true;
+
+    std::string tuning_str = (constraints.force_frac0) ? "Integer-N" : "Fractional";
+
+    UHD_LOGV(often)
+        << boost::format("ADF 435X Frequencies (MHz): REQUESTED=%0.9f, ACTUAL=%0.9f"
+        ) % (target_freq/1e6) % (actual_freq/1e6) << std::endl
+        << boost::format("ADF 435X Intermediates (MHz): VCO=%0.2f, PFD=%0.2f, BAND=%0.2f, REF=%0.2f"
+        ) % (vco_freq/1e6) % (pfd_freq/1e6) % (pfd_freq/BS/1e6) % (ref_freq/1e6) << std::endl
+        << boost::format("ADF 435X Tuning: %s") % tuning_str.c_str() << std::endl
+        << boost::format("ADF 435X Settings: R=%d, BS=%d, N=%d, FRAC=%d, MOD=%d, T=%d, D=%d, RFdiv=%d"
+        ) % R % BS % N % FRAC % MOD % T % D % RFdiv << std::endl;
+
+    UHD_ASSERT_THROW((settings.frac_12_bit          & ((boost::uint16_t)~0xFFF)) == 0);
+    UHD_ASSERT_THROW((settings.mod_12_bit           & ((boost::uint16_t)~0xFFF)) == 0);
+    UHD_ASSERT_THROW((settings.clock_divider_12_bit & ((boost::uint16_t)~0xFFF)) == 0);
+    UHD_ASSERT_THROW((settings.r_counter_10_bit     & ((boost::uint16_t)~0x3FF)) == 0);
+
+    UHD_ASSERT_THROW(vco_freq >= MIN_VCO_FREQ and vco_freq <= MAX_VCO_FREQ);
+    UHD_ASSERT_THROW(settings.rf_divider >= static_cast<boost::uint16_t>(constraints.rf_divider_range.start()));
+    UHD_ASSERT_THROW(settings.rf_divider <= static_cast<boost::uint16_t>(constraints.rf_divider_range.stop()));
+    UHD_ASSERT_THROW(settings.int_16_bit >= static_cast<boost::uint16_t>(constraints.int_range.start()));
+    UHD_ASSERT_THROW(settings.int_16_bit <= static_cast<boost::uint16_t>(constraints.int_range.stop()));
+
+    return settings;
+}