CBX support

1 files changed, 212 insertions, 0 deletions

diff --git a/host/lib/usrp/dboard/db_cbx.cpp b/host/lib/usrp/dboard/db_cbx.cpp
new file mode 100644
index 000000000..04399e64e
--- /dev/null
+++ b/host/lib/usrp/dboard/db_cbx.cpp
@@ -0,0 +1,212 @@
+//
+// Copyright 2011-2012 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/>.
+//
+
+
+#include "max2870_regs.hpp"
+#include "db_sbx_common.hpp"
+
+
+using namespace uhd;
+using namespace uhd::usrp;
+using namespace boost::assign;
+
+/***********************************************************************
+ * Structors
+ **********************************************************************/
+sbx_xcvr::cbx::cbx(sbx_xcvr *_self_sbx_xcvr) {
+    //register the handle to our base CBX class
+    self_base = _self_sbx_xcvr;
+}
+
+
+sbx_xcvr::cbx::~cbx(void){
+    /* NOP */
+}
+
+
+/***********************************************************************
+ * Tuning
+ **********************************************************************/
+double sbx_xcvr::cbx::set_lo_freq(dboard_iface::unit_t unit, double target_freq) {
+    UHD_LOGV(often) << boost::format(
+        "CBX tune: target frequency %f Mhz"
+    ) % (target_freq/1e6) << std::endl;
+
+    //clip the input
+    target_freq = cbx_freq_range.clip(target_freq);
+
+    //map mode setting to valid integer divider (N) values
+    static const uhd::range_t int_n_mode_div_range(16,4095,1);
+    static const uhd::range_t frac_n_mode_div_range(19,4091,1);
+
+    //map rf divider select output dividers to enums
+    static const uhd::dict<int, max2870_regs_t::rf_divider_select_t> rfdivsel_to_enum = map_list_of
+        (1,   max2870_regs_t::RF_DIVIDER_SELECT_DIV1)
+        (2,   max2870_regs_t::RF_DIVIDER_SELECT_DIV2)
+        (4,   max2870_regs_t::RF_DIVIDER_SELECT_DIV4)
+        (8,   max2870_regs_t::RF_DIVIDER_SELECT_DIV8)
+        (16,  max2870_regs_t::RF_DIVIDER_SELECT_DIV16)
+        (32,  max2870_regs_t::RF_DIVIDER_SELECT_DIV32)
+        (64,  max2870_regs_t::RF_DIVIDER_SELECT_DIV64)
+        (128, max2870_regs_t::RF_DIVIDER_SELECT_DIV128)
+    ;
+    
+    double actual_freq, pfd_freq;
+    double ref_freq = self_base->get_iface()->get_clock_rate(unit);
+    max2870_regs_t::int_n_mode_t int_n_mode;
+    int R=0, BS=0, N=0, FRAC=0, MOD=4095;
+    int RFdiv = 1;
+    max2870_regs_t::reference_divide_by_2_t T     = max2870_regs_t::REFERENCE_DIVIDE_BY_2_DISABLED;
+    max2870_regs_t::reference_doubler_t     D     = max2870_regs_t::REFERENCE_DOUBLER_DISABLED;    
+
+    //Reference doubler for 50% duty cycle
+    // if ref_freq < 12.5MHz enable regs.reference_divide_by_2
+    //NOTE: MAX2870 goes down to 10MHz ref vs. 12.5MHz on ADF4351
+    if(ref_freq <= 10.0e6) D = max2870_regs_t::REFERENCE_DOUBLER_ENABLED;
+
+    //increase RF divider until acceptable VCO frequency
+    double vco_freq = target_freq;
+    //NOTE: MIN freq for MAX2870 VCO is 3GHz vs. 2.2GHz on ADF4351
+    while (vco_freq < 3e9) {
+        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
+     */
+    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*(1+D)/(R*(1+T));
+
+        //keep the PFD frequency at or below 25MHz
+        if (pfd_freq > 25e6) continue;
+
+        //ignore fractional part of tuning
+        N = int(vco_freq/pfd_freq);
+
+        //Fractional-N calculation
+        FRAC = int((vco_freq/pfd_freq - N)*MOD);
+
+        //are we in int-N or frac-N mode?
+        int_n_mode = (FRAC == 0) ? max2870_regs_t::INT_N_MODE_INT_N : max2870_regs_t::INT_N_MODE_FRAC_N;
+
+        //keep N within int divider requirements
+        if(int_n_mode == max2870_regs_t::INT_N_MODE_INT_N) {
+            if(N < int_n_mode_div_range.start()) continue;
+            if(N > int_n_mode_div_range.stop()) continue;
+        } else {
+            if(N < frac_n_mode_div_range.start()) continue;
+            if(N > frac_n_mode_div_range.stop()) continue;
+        }
+
+        //keep pfd freq low enough to achieve 50kHz BS clock
+        BS = std::ceil(pfd_freq / 50e3);
+        if(BS <= 1023) break;
+    }
+
+    UHD_ASSERT_THROW(R <= 1023);
+
+    //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 = max2870_regs_t::REFERENCE_DIVIDE_BY_2_ENABLED;
+        R /= 2;
+    }
+
+    //actual frequency calculation
+    actual_freq = double((N + (double(FRAC)/double(MOD)))*ref_freq*(1+int(D))/(R*(1+int(T)))/RFdiv);
+
+    UHD_LOGV(often)
+        << boost::format("CBX Intermediates: ref=%0.2f, outdiv=%f, fbdiv=%f") % (ref_freq*(1+int(D))/(R*(1+int(T)))) % double(RFdiv*2) % double(N + double(FRAC)/double(MOD)) << std::endl
+        << boost::format("CBX tune: 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
+        << boost::format("CBX Frequencies (MHz): REQ=%0.2f, ACT=%0.2f, VCO=%0.2f, PFD=%0.2f, BAND=%0.2f"
+            ) % (target_freq/1e6) % (actual_freq/1e6) % (vco_freq/1e6) % (pfd_freq/1e6) % (pfd_freq/BS/1e6) << std::endl;
+
+    //load the register values
+    max2870_regs_t regs;
+
+    if ((unit == dboard_iface::UNIT_TX) and (actual_freq == sbx_tx_lo_2dbm.clip(actual_freq))) 
+        regs.output_power = max2870_regs_t::OUTPUT_POWER_2DBM;
+    else
+        regs.output_power = max2870_regs_t::OUTPUT_POWER_5DBM;
+
+    //set frac/int CPL mode
+    max2870_regs_t::cpl_t cpl;
+    max2870_regs_t::ldf_t ldf;
+    max2870_regs_t::cpoc_t cpoc;
+    if(int_n_mode == max2870_regs_t::INT_N_MODE_INT_N) {
+        cpl = max2870_regs_t::CPL_DISABLED;
+        cpoc = max2870_regs_t::CPOC_ENABLED;
+        ldf = max2870_regs_t::LDF_INT_N;
+    } else {
+        cpl = max2870_regs_t::CPL_ENABLED;
+        ldf = max2870_regs_t::LDF_FRAC_N;
+        cpoc = max2870_regs_t::CPOC_DISABLED;
+    }
+
+    regs.frac_12_bit = FRAC;
+    regs.int_16_bit = N;
+    regs.mod_12_bit = MOD;
+    regs.clock_divider_12_bit = std::max(1, int(std::ceil(400e-6*pfd_freq/MOD)));
+    regs.feedback_select = (target_freq >= 3.0e9) ? max2870_regs_t::FEEDBACK_SELECT_DIVIDED : max2870_regs_t::FEEDBACK_SELECT_FUNDAMENTAL;
+    regs.r_counter_10_bit = R;
+    regs.reference_divide_by_2 = T;
+    regs.reference_doubler = D;
+    regs.band_select_clock_div = BS;
+    UHD_ASSERT_THROW(rfdivsel_to_enum.has_key(RFdiv));
+    regs.rf_divider_select = rfdivsel_to_enum[RFdiv];
+    regs.int_n_mode = int_n_mode;
+    regs.cpl = cpl;
+    regs.ldf = ldf;
+    regs.cpoc = cpoc;    
+
+    //write the registers
+    //correct power-up sequence to write registers (5, 4, 3, 2, 1, 0)
+    int addr;
+
+    for(addr=5; addr>=0; addr--){
+        UHD_LOGV(often) << boost::format(
+            "CBX SPI Reg (0x%02x): 0x%08x"
+        ) % addr % regs.get_reg(addr) << std::endl;
+        self_base->get_iface()->write_spi(
+            unit, spi_config_t::EDGE_RISE,
+            regs.get_reg(addr), 32
+        );
+    }
+
+    //return the actual frequency
+    UHD_LOGV(often) << boost::format(
+        "CBX tune: actual frequency %f Mhz"
+    ) % (actual_freq/1e6) << std::endl;
+    return actual_freq;
+}
+