Merge branch 'master' into usrp2p

this was the merge from hell

Conflicts:

	firmware/microblaze/Makefile.am
	firmware/microblaze/bootstrap
	firmware/microblaze/configure.ac
	firmware/microblaze/lib/Makefile.inc
	host/lib/CMakeLists.txt
	host/lib/usrp/mimo_usrp.cpp
	host/lib/usrp/simple_usrp.cpp
	host/lib/usrp/usrp2/clock_ctrl.cpp
	host/lib/usrp/usrp2/codec_impl.cpp
	host/lib/usrp/usrp2/dboard_impl.cpp
	host/lib/usrp/usrp2/mboard_impl.cpp
	host/lib/usrp/usrp2/usrp2_iface.hpp
	host/lib/usrp/usrp2/usrp2_impl.hpp
	host/lib/usrp/usrp2/usrp2_regs.hpp
	host/test/CMakeLists.txt

18 files changed, 1002 insertions, 207 deletions

diff --git a/host/lib/usrp/CMakeLists.txt b/host/lib/usrp/CMakeLists.txt
index 4f0710b20..d951ab412 100644
--- a/host/lib/usrp/CMakeLists.txt
+++ b/host/lib/usrp/CMakeLists.txt
@@ -27,5 +27,9 @@ LIBUHD_APPEND_SOURCES(
     ${CMAKE_SOURCE_DIR}/lib/usrp/misc_utils.cpp
     ${CMAKE_SOURCE_DIR}/lib/usrp/misc_utils.hpp
     ${CMAKE_SOURCE_DIR}/lib/usrp/simple_usrp.cpp
+    ${CMAKE_SOURCE_DIR}/lib/usrp/subdev_spec.cpp
     ${CMAKE_SOURCE_DIR}/lib/usrp/tune_helper.cpp
 )
+
+INCLUDE(${CMAKE_SOURCE_DIR}/lib/usrp/dboard/CMakeLists.txt)
+INCLUDE(${CMAKE_SOURCE_DIR}/lib/usrp/usrp2/CMakeLists.txt)
diff --git a/host/lib/usrp/dboard/CMakeLists.txt b/host/lib/usrp/dboard/CMakeLists.txt
index 6093583d3..3e995009e 100644
--- a/host/lib/usrp/dboard/CMakeLists.txt
+++ b/host/lib/usrp/dboard/CMakeLists.txt
@@ -22,6 +22,7 @@ LIBUHD_APPEND_SOURCES(
     ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_rfx.cpp
     ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_xcvr2450.cpp
     ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_wbx.cpp
+    ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_dbsrx.cpp
     ${CMAKE_SOURCE_DIR}/lib/usrp/dboard/db_unknown.cpp
 )
 
diff --git a/host/lib/usrp/dboard/db_dbsrx.cpp b/host/lib/usrp/dboard/db_dbsrx.cpp
new file mode 100644
index 000000000..03e6b6255
--- /dev/null
+++ b/host/lib/usrp/dboard/db_dbsrx.cpp
@@ -0,0 +1,610 @@
+//
+// Copyright 2010 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/>.
+//
+
+// No RX IO Pins Used
+
+// RX IO Functions
+
+#include "max2118_regs.hpp"
+#include <uhd/utils/static.hpp>
+#include <uhd/utils/assert.hpp>
+#include <uhd/utils/algorithm.hpp>
+#include <uhd/utils/warning.hpp>
+#include <uhd/types/ranges.hpp>
+#include <uhd/types/dict.hpp>
+#include <uhd/usrp/subdev_props.hpp>
+#include <uhd/usrp/dboard_base.hpp>
+#include <uhd/usrp/dboard_manager.hpp>
+#include <boost/assign/list_of.hpp>
+#include <boost/format.hpp>
+#include <boost/thread.hpp>
+#include <boost/math/special_functions/round.hpp>
+#include <utility>
+#include <cmath>
+
+using namespace uhd;
+using namespace uhd::usrp;
+using namespace boost::assign;
+
+/***********************************************************************
+ * The DBSRX constants
+ **********************************************************************/
+static const bool dbsrx_debug = false;
+
+static const freq_range_t dbsrx_freq_range(0.8e9, 2.4e9);
+
+static const freq_range_t dbsrx_pfd_freq_range(0.15e6, 2.01e6);
+
+static const prop_names_t dbsrx_antennas = list_of("J3");
+
+static const uhd::dict<std::string, gain_range_t> dbsrx_gain_ranges = map_list_of
+    ("GC1", gain_range_t(0, 56, 0.5))
+    ("GC2", gain_range_t(0, 24, 1))
+;
+
+/***********************************************************************
+ * The DBSRX dboard class
+ **********************************************************************/
+class dbsrx : public rx_dboard_base{
+public:
+    dbsrx(ctor_args_t args, boost::uint8_t max2118_addr);
+    ~dbsrx(void);
+
+    void rx_get(const wax::obj &key, wax::obj &val);
+    void rx_set(const wax::obj &key, const wax::obj &val);
+
+private:
+    double _lo_freq;
+    float _bandwidth;
+    uhd::dict<std::string, float> _gains;
+    max2118_write_regs_t _max2118_write_regs;
+    max2118_read_regs_t _max2118_read_regs;
+    boost::uint8_t _max2118_addr; //0x67 or 0x65 depending on which side
+
+    void set_lo_freq(double target_freq);
+    void set_gain(float gain, const std::string &name);
+    void set_bandwidth(float bandwidth);
+
+    void send_reg(boost::uint8_t start_reg, boost::uint8_t stop_reg){
+        start_reg = boost::uint8_t(std::clip(int(start_reg), 0x0, 0x5));
+        stop_reg = boost::uint8_t(std::clip(int(stop_reg), 0x0, 0x5));
+
+        for(boost::uint8_t start_addr=start_reg; start_addr <= stop_reg; start_addr += sizeof(boost::uint32_t) - 1){
+            int num_bytes = int(stop_reg - start_addr + 1) > int(sizeof(boost::uint32_t)) - 1 ? sizeof(boost::uint32_t) - 1 : stop_reg - start_addr + 1;
+
+            //create buffer for register data (+1 for start address)
+            byte_vector_t regs_vector(num_bytes + 1);
+
+            //first byte is the address of first register
+            regs_vector[0] = start_addr;
+
+            //get the register data
+            for(int i=0; i<num_bytes; i++){
+                regs_vector[1+i] = _max2118_write_regs.get_reg(start_addr+i);
+                if(dbsrx_debug) std::cerr << boost::format(
+                    "DBSRX: send reg 0x%02x, value 0x%04x, start_addr = 0x%04x, num_bytes %d"
+                ) % int(start_addr+i) % int(regs_vector[1+i]) % int(start_addr) % num_bytes << std::endl;
+            }
+
+            //send the data
+            this->get_iface()->write_i2c(
+                _max2118_addr, regs_vector
+            );
+        }
+    }
+
+    void read_reg(boost::uint8_t start_reg, boost::uint8_t stop_reg){
+        static const boost::uint8_t status_addr = 0x0;
+        start_reg = boost::uint8_t(std::clip(int(start_reg), 0x0, 0x1));
+        stop_reg = boost::uint8_t(std::clip(int(stop_reg), 0x0, 0x1));
+
+        for(boost::uint8_t start_addr=start_reg; start_addr <= stop_reg; start_addr += sizeof(boost::uint32_t)){
+            int num_bytes = int(stop_reg - start_addr + 1) > int(sizeof(boost::uint32_t)) ? sizeof(boost::uint32_t) : stop_reg - start_addr + 1;
+
+            //create buffer for register data
+            byte_vector_t regs_vector(num_bytes);
+
+            //read from i2c
+            regs_vector = this->get_iface()->read_i2c(
+                _max2118_addr, num_bytes
+            );
+
+            for(boost::uint8_t i=0; i < num_bytes; i++){
+                if (i + start_addr >= status_addr){
+                    _max2118_read_regs.set_reg(i + start_addr, regs_vector[i]);
+                }
+                if(dbsrx_debug) std::cerr << boost::format(
+                    "DBSRX: read reg 0x%02x, value 0x%04x, start_addr = 0x%04x, num_bytes %d"
+                ) % int(start_addr+i) % int(regs_vector[i]) % int(start_addr) % num_bytes << std::endl;
+            }
+        }
+    }
+
+    /*!
+     * Is the LO locked?
+     * \return true for locked
+     */
+    bool get_locked(void){
+        read_reg(0x0, 0x0);
+
+        //mask and return lock detect
+        bool locked = 5 >= _max2118_read_regs.adc and _max2118_read_regs.adc >= 2;
+
+        if(dbsrx_debug) std::cerr << boost::format(
+            "DBSRX: locked %d"
+        ) % locked << std::endl;
+
+        return locked;
+    }
+
+};
+
+/***********************************************************************
+ * Register the DBSRX dboard
+ **********************************************************************/
+// FIXME 0x67 is the default i2c address on USRP2
+//       need to handle which side for USRP1 with different address
+static dboard_base::sptr make_dbsrx(dboard_base::ctor_args_t args){
+    return dboard_base::sptr(new dbsrx(args, 0x67));
+}
+
+//dbid for USRP2 version
+UHD_STATIC_BLOCK(reg_dbsrx_dboard){
+    //register the factory function for the rx dbid
+    dboard_manager::register_dboard(0x000D, &make_dbsrx, "DBSRX");
+}
+
+//dbid for USRP1 version
+UHD_STATIC_BLOCK(reg_dbsrx_on_usrp1_dboard){
+    //register the factory function for the rx dbid
+    dboard_manager::register_dboard(0x0002, &make_dbsrx, "DBSRX");
+}
+
+/***********************************************************************
+ * Structors
+ **********************************************************************/
+dbsrx::dbsrx(ctor_args_t args, boost::uint8_t max2118_addr) : rx_dboard_base(args){
+    //warn user about incorrect DBID on USRP1, requires R193 populated
+    if (this->get_iface()->get_mboard_name() == "usrp1" and this->get_rx_id() == 0x000D)
+        uhd::print_warning(
+            str(boost::format(
+                "DBSRX: incorrect dbid\n"
+                "%s expects dbid 0x0002 and R193\n"
+                "found dbid == %d\n"
+                "Please see the daughterboard app notes" 
+                ) % (this->get_iface()->get_mboard_name()) % (this->get_rx_id().to_pp_string()))
+        );
+
+    //warn user about incorrect DBID on non-USRP1, requires R194 populated
+    if (this->get_iface()->get_mboard_name() != "usrp1" and this->get_rx_id() == 0x0002)
+        uhd::print_warning(
+            str(boost::format(
+                "DBSRX: incorrect dbid\n"
+                "%s expects dbid 0x000D and R194\n"
+                "found dbid == %d\n"
+                "Please see the daughterboard app notes" 
+                ) % (this->get_iface()->get_mboard_name()) % (this->get_rx_id().to_pp_string()))
+        );
+
+    //enable only the clocks we need
+    this->get_iface()->set_clock_enabled(dboard_iface::UNIT_RX, true);
+
+    //set the gpio directions and atr controls (identically)
+    this->get_iface()->set_pin_ctrl(dboard_iface::UNIT_RX, 0x0); // All unused in atr
+    this->get_iface()->set_gpio_ddr(dboard_iface::UNIT_RX, 0x0); // All Inputs
+
+    //set the i2c address for the max2118
+    _max2118_addr = max2118_addr;
+
+    //send initial register settings
+    this->send_reg(0x0, 0x5);
+
+    //set defaults for LO, gains, and filter bandwidth
+    _bandwidth = 33e6;
+    set_lo_freq(dbsrx_freq_range.min);
+
+    BOOST_FOREACH(const std::string &name, dbsrx_gain_ranges.keys()){
+        set_gain(dbsrx_gain_ranges[name].min, name);
+    }
+
+    set_bandwidth(33e6); // default bandwidth from datasheet
+}
+
+dbsrx::~dbsrx(void){
+}
+
+
+/***********************************************************************
+ * Tuning
+ **********************************************************************/
+void dbsrx::set_lo_freq(double target_freq){
+    target_freq = std::clip(target_freq, dbsrx_freq_range.min, dbsrx_freq_range.max);
+
+    double actual_freq=0.0, pfd_freq=0.0, ref_clock=0.0;
+    int R=0, N=0, r=0, m=0;
+    bool update_filter_settings = false;
+
+    //choose refclock
+    std::vector<double> clock_rates = this->get_iface()->get_clock_rates(dboard_iface::UNIT_RX);
+    BOOST_FOREACH(ref_clock, std::reversed(std::sorted(clock_rates))){
+        if (ref_clock > 27.0e6) continue;
+
+        //choose m_divider such that filter tuning constraint is met
+        m = 31;
+        while ((ref_clock/m < 1e6 or ref_clock/m > 2.5e6) and m > 0){ m--; }
+
+        if(dbsrx_debug) std::cerr << boost::format(
+            "DBSRX: trying ref_clock %f and m_divider %d"
+        ) % (this->get_iface()->get_clock_rate(dboard_iface::UNIT_RX)) % m << std::endl;
+
+        if (m >= 32) continue;
+
+        //choose R
+        for(r = 0; r <= 6; r += 1) {
+            //compute divider from setting
+            R = 1 << (r+1);
+            if (dbsrx_debug) std::cerr << boost::format("DBSRX R:%d\n") % R << std::endl;
+
+            //compute PFD compare frequency = ref_clock/R
+            pfd_freq = ref_clock / R;
+
+            //constrain the PFD frequency to specified range
+            if ((pfd_freq < dbsrx_pfd_freq_range.min) or (pfd_freq > dbsrx_pfd_freq_range.max)) continue;
+
+            //compute N
+            N = int(std::floor(target_freq/pfd_freq));
+
+            //constrain N to specified range
+            if ((N < 256) or (N > 32768)) continue;
+
+            goto done_loop;
+        }
+    } 
+
+    //Assert because we failed to find a suitable combination of ref_clock, R and N 
+    UHD_ASSERT_THROW(ref_clock/(1 << m) < 1e6 or ref_clock/(1 << m) > 2.5e6);
+    UHD_ASSERT_THROW((pfd_freq < dbsrx_pfd_freq_range.min) or (pfd_freq > dbsrx_pfd_freq_range.max));
+    UHD_ASSERT_THROW((N < 256) or (N > 32768));
+    done_loop:
+
+    if(dbsrx_debug) std::cerr << boost::format(
+        "DBSRX: choose ref_clock %f and m_divider %d"
+    ) % (this->get_iface()->get_clock_rate(dboard_iface::UNIT_RX)) % m << std::endl;
+
+    //if ref_clock or m divider changed, we need to update the filter settings
+    if (ref_clock != this->get_iface()->get_clock_rate(dboard_iface::UNIT_RX) or m != _max2118_write_regs.m_divider) update_filter_settings = true;
+
+    //compute resulting output frequency
+    actual_freq = pfd_freq * N;
+
+    //apply ref_clock, R, and N settings
+    this->get_iface()->set_clock_rate(dboard_iface::UNIT_RX, ref_clock);
+    ref_clock = this->get_iface()->get_clock_rate(dboard_iface::UNIT_RX);
+    _max2118_write_regs.m_divider = m;
+    _max2118_write_regs.r_divider = (max2118_write_regs_t::r_divider_t) r;
+    _max2118_write_regs.set_n_divider(N);
+    _max2118_write_regs.ade_vco_ade_read = max2118_write_regs_t::ADE_VCO_ADE_READ_ENABLED;
+    
+    //compute prescaler variables
+    int scaler = actual_freq > 1125e6 ? 2 : 4;
+    _max2118_write_regs.div2 = scaler == 4 ? max2118_write_regs_t::DIV2_DIV4 : max2118_write_regs_t::DIV2_DIV2;
+
+    if(dbsrx_debug) std::cerr << boost::format(
+        "DBSRX: scaler %d, actual_freq %f MHz, register bit: %d"
+    ) % scaler % (actual_freq/1e6) % int(_max2118_write_regs.div2) << std::endl;
+
+    //compute vco frequency and select vco
+    double vco_freq = actual_freq * scaler;
+    if (vco_freq < 2433e6)
+        _max2118_write_regs.osc_band = 0;
+    else if (vco_freq < 2711e6)
+        _max2118_write_regs.osc_band = 1;
+    else if (vco_freq < 3025e6)
+        _max2118_write_regs.osc_band = 2;
+    else if (vco_freq < 3341e6)
+        _max2118_write_regs.osc_band = 3;
+    else if (vco_freq < 3727e6)
+        _max2118_write_regs.osc_band = 4;
+    else if (vco_freq < 4143e6)
+        _max2118_write_regs.osc_band = 5;
+    else if (vco_freq < 4493e6)
+        _max2118_write_regs.osc_band = 6;
+    else
+        _max2118_write_regs.osc_band = 7;
+
+    //send settings over i2c
+    send_reg(0x0, 0x4);
+
+    //check vtune for lock condition
+    read_reg(0x0, 0x0);
+
+    if(dbsrx_debug) std::cerr << boost::format(
+        "DBSRX: initial guess for vco %d, vtune adc %d"
+    ) % int(_max2118_write_regs.osc_band) % int(_max2118_read_regs.adc) << std::endl;
+
+    //if we are out of lock for chosen vco, change vco
+    while ((_max2118_read_regs.adc == 0) or (_max2118_read_regs.adc == 7)){
+
+        //vtune is too low, try lower frequency vco
+        if (_max2118_read_regs.adc == 0){
+            if (_max2118_write_regs.osc_band == 0){
+                uhd::print_warning(
+                    str(boost::format(
+                        "DBSRX: Tuning exceeded vco range, _max2118_write_regs.osc_band == %d\n" 
+                        ) % int(_max2118_write_regs.osc_band))
+                );
+                UHD_ASSERT_THROW(_max2118_read_regs.adc == 0);
+            }
+            if (_max2118_write_regs.osc_band <= 0) break;
+            _max2118_write_regs.osc_band -= 1;
+        }
+
+        //vtune is too high, try higher frequency vco
+        if (_max2118_read_regs.adc == 7){
+            if (_max2118_write_regs.osc_band == 7){
+                uhd::print_warning(
+                    str(boost::format(
+                        "DBSRX: Tuning exceeded vco range, _max2118_write_regs.osc_band == %d\n" 
+                        ) % int(_max2118_write_regs.osc_band))
+                );
+                UHD_ASSERT_THROW(_max2118_read_regs.adc == 0);
+            }
+            if (_max2118_write_regs.osc_band >= 7) break;
+            _max2118_write_regs.osc_band += 1;
+        }
+
+        if(dbsrx_debug) std::cerr << boost::format(
+            "DBSRX: trying vco %d, vtune adc %d"
+        ) % int(_max2118_write_regs.osc_band) % int(_max2118_read_regs.adc) << std::endl;
+
+        //update vco selection and check vtune
+        send_reg(0x2, 0x2);
+        read_reg(0x0, 0x0);
+    }
+      
+    if(dbsrx_debug) std::cerr << boost::format(
+        "DBSRX: final vco %d, vtune adc %d"
+    ) % int(_max2118_write_regs.osc_band) % int(_max2118_read_regs.adc) << std::endl;
+
+    //select charge pump bias current
+    if (_max2118_read_regs.adc <= 2) _max2118_write_regs.cp_current = max2118_write_regs_t::CP_CURRENT_I_CP_100UA;
+    else if (_max2118_read_regs.adc >= 5) _max2118_write_regs.cp_current = max2118_write_regs_t::CP_CURRENT_I_CP_400UA;
+    else _max2118_write_regs.cp_current = max2118_write_regs_t::CP_CURRENT_I_CP_200UA;
+    
+    //update charge pump bias current setting
+    send_reg(0x2, 0x2);
+
+    //compute actual tuned frequency
+    _lo_freq = this->get_iface()->get_clock_rate(dboard_iface::UNIT_RX) / std::pow(2.0,(1 + _max2118_write_regs.r_divider)) * _max2118_write_regs.get_n_divider();
+
+    //debug output of calculated variables
+    if (dbsrx_debug) std::cerr
+        << boost::format("DBSRX tune:\n")
+        << boost::format("    VCO=%d, CP=%d, PFD Freq=%fMHz\n") % int(_max2118_write_regs.osc_band) % _max2118_write_regs.cp_current % (pfd_freq/1e6)
+        << boost::format("    R=%d, N=%f, scaler=%d, div2=%d\n") % R % N % scaler % int(_max2118_write_regs.div2)
+        << boost::format("    Ref    Freq=%fMHz\n") % (ref_clock/1e6)
+        << boost::format("    Target Freq=%fMHz\n") % (target_freq/1e6)
+        << boost::format("    Actual Freq=%fMHz\n") % (_lo_freq/1e6)
+        << std::endl;
+
+    if (update_filter_settings) set_bandwidth(_bandwidth);
+    get_locked();
+}
+
+/***********************************************************************
+ * Gain Handling
+ **********************************************************************/
+/*!
+ * Convert a requested gain for the GC2 vga into the integer register value.
+ * The gain passed into the function will be set to the actual value.
+ * \param gain the requested gain in dB
+ * \return 5 bit the register value
+ */
+static int gain_to_gc2_vga_reg(float &gain){
+    int reg = 0;
+    gain = std::clip<float>(float(boost::math::iround(gain)), dbsrx_gain_ranges["GC2"].min, dbsrx_gain_ranges["GC2"].max);
+
+    // Half dB steps from 0-5dB, 1dB steps from 5-24dB
+    if (gain < 5) {
+        reg = boost::math::iround(31.0 - gain/0.5);
+        gain = float(boost::math::iround(gain) * 0.5);
+    } else {
+        reg = boost::math::iround(22.0 - (gain - 4.0));
+        gain = float(boost::math::iround(gain));
+    }
+
+    if (dbsrx_debug) std::cerr << boost::format(
+        "DBSRX GC2 Gain: %f dB, reg: %d"
+    ) % gain % reg << std::endl;
+
+    return reg;
+}
+
+/*!
+ * Convert a requested gain for the GC1 rf vga into the dac_volts value.
+ * The gain passed into the function will be set to the actual value.
+ * \param gain the requested gain in dB
+ * \return dac voltage value
+ */
+static float gain_to_gc1_rfvga_dac(float &gain){
+    //clip the input
+    gain = std::clip<float>(gain, dbsrx_gain_ranges["GC1"].min, dbsrx_gain_ranges["GC1"].max);
+
+    //voltage level constants
+    static const float max_volts = float(1.2), min_volts = float(2.7);
+    static const float slope = (max_volts-min_volts)/dbsrx_gain_ranges["GC1"].max;
+
+    //calculate the voltage for the aux dac
+    float dac_volts = gain*slope + min_volts;
+
+    if (dbsrx_debug) std::cerr << boost::format(
+        "DBSRX GC1 Gain: %f dB, dac_volts: %f V"
+    ) % gain % dac_volts << std::endl;
+
+    //the actual gain setting
+    gain = (dac_volts - min_volts)/slope;
+
+    return dac_volts;
+}
+
+void dbsrx::set_gain(float gain, const std::string &name){
+    assert_has(dbsrx_gain_ranges.keys(), name, "dbsrx gain name");
+    if (name == "GC2"){
+        _max2118_write_regs.gc2 = gain_to_gc2_vga_reg(gain);
+        send_reg(0x5, 0x5);
+    }
+    else if(name == "GC1"){
+        //write the new voltage to the aux dac
+        this->get_iface()->write_aux_dac(dboard_iface::UNIT_RX, dboard_iface::AUX_DAC_A, gain_to_gc1_rfvga_dac(gain));
+    }
+    else UHD_THROW_INVALID_CODE_PATH();
+    _gains[name] = gain;
+}
+
+/***********************************************************************
+ * Bandwidth Handling
+ **********************************************************************/
+void dbsrx::set_bandwidth(float bandwidth){
+    //clip the input
+    bandwidth = std::clip<float>(bandwidth, 4e6, 33e6);
+
+    double ref_clock = this->get_iface()->get_clock_rate(dboard_iface::UNIT_RX);
+    
+    //NOTE: _max2118_write_regs.m_divider set in set_lo_freq
+
+    //compute f_dac setting
+    _max2118_write_regs.f_dac = std::clip<int>(int((((bandwidth*_max2118_write_regs.m_divider)/ref_clock) - 4)/0.145),0,127);
+
+    //determine actual bandwidth
+    _bandwidth = float((ref_clock/(_max2118_write_regs.m_divider))*(4+0.145*_max2118_write_regs.f_dac));
+
+    if (dbsrx_debug) std::cerr << boost::format(
+        "DBSRX Filter Bandwidth: %f MHz, m: %d, f_dac: %d\n"
+    ) % (_bandwidth/1e6) % int(_max2118_write_regs.m_divider) % int(_max2118_write_regs.f_dac) << std::endl;
+
+    this->send_reg(0x3, 0x4);
+}
+
+/***********************************************************************
+ * RX Get and Set
+ **********************************************************************/
+void dbsrx::rx_get(const wax::obj &key_, wax::obj &val){
+    wax::obj key; std::string name;
+    boost::tie(key, name) = extract_named_prop(key_);
+
+    //handle the get request conditioned on the key
+    switch(key.as<subdev_prop_t>()){
+    case SUBDEV_PROP_NAME:
+        val = get_rx_id().to_pp_string();
+        return;
+
+    case SUBDEV_PROP_OTHERS:
+        val = prop_names_t(); //empty
+        return;
+
+    case SUBDEV_PROP_GAIN:
+        assert_has(_gains.keys(), name, "dbsrx gain name");
+        val = _gains[name];
+        return;
+
+    case SUBDEV_PROP_GAIN_RANGE:
+        assert_has(dbsrx_gain_ranges.keys(), name, "dbsrx gain name");
+        val = dbsrx_gain_ranges[name];
+        return;
+
+    case SUBDEV_PROP_GAIN_NAMES:
+        val = prop_names_t(dbsrx_gain_ranges.keys());
+        return;
+
+    case SUBDEV_PROP_FREQ:
+        val = _lo_freq;
+        return;
+
+    case SUBDEV_PROP_FREQ_RANGE:
+        val = dbsrx_freq_range;
+        return;
+
+    case SUBDEV_PROP_ANTENNA:
+        val = std::string("J3");
+        return;
+
+    case SUBDEV_PROP_ANTENNA_NAMES:
+        val = dbsrx_antennas;
+        return;
+
+/*
+    case SUBDEV_PROP_QUADRATURE:
+        val = true;
+        return;
+
+    case SUBDEV_PROP_IQ_SWAPPED:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_SPECTRUM_INVERTED:
+        val = false;
+        return;
+*/
+    case SUBDEV_PROP_CONNECTION:
+        val = SUBDEV_CONN_COMPLEX_IQ;
+        return;
+
+    case SUBDEV_PROP_USE_LO_OFFSET:
+        val = false;
+        return;
+
+    case SUBDEV_PROP_LO_LOCKED:
+        val = this->get_locked();
+        return;
+
+/*
+    case SUBDEV_PROP_RSSI:
+        val = this->get_rssi();
+        return;
+*/
+
+    case SUBDEV_PROP_BANDWIDTH:
+        val = _bandwidth;
+        return;
+
+    default: UHD_THROW_PROP_GET_ERROR();
+    }
+}
+
+void dbsrx::rx_set(const wax::obj &key_, const wax::obj &val){
+    wax::obj key; std::string name;
+    boost::tie(key, name) = extract_named_prop(key_);
+
+    //handle the get request conditioned on the key
+    switch(key.as<subdev_prop_t>()){
+
+    case SUBDEV_PROP_FREQ:
+        this->set_lo_freq(val.as<double>());
+        return;
+
+    case SUBDEV_PROP_GAIN:
+        this->set_gain(val.as<float>(), name);
+        return;
+
+    case SUBDEV_PROP_BANDWIDTH:
+        this->set_bandwidth(val.as<float>());
+        return;
+
+    default: UHD_THROW_PROP_SET_ERROR();
+    }
+}
+
diff --git a/host/lib/usrp/dboard/db_rfx.cpp b/host/lib/usrp/dboard/db_rfx.cpp
index 914ca5e19..b6b44199a 100644
--- a/host/lib/usrp/dboard/db_rfx.cpp
+++ b/host/lib/usrp/dboard/db_rfx.cpp
@@ -43,6 +43,7 @@
 #include <uhd/utils/assert.hpp>
 #include <uhd/utils/static.hpp>
 #include <uhd/utils/algorithm.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>
@@ -65,6 +66,10 @@ static const prop_names_t rfx_rx_antennas = list_of("TX/RX")("RX2");
 static const uhd::dict<std::string, gain_range_t> rfx_tx_gain_ranges; //empty
 
 static const uhd::dict<std::string, gain_range_t> rfx_rx_gain_ranges = map_list_of
+    ("PGA0", gain_range_t(0, 70, float(0.022)))
+;
+
+static const uhd::dict<std::string, gain_range_t> rfx400_rx_gain_ranges = map_list_of
     ("PGA0", gain_range_t(0, 45, float(0.022)))
 ;
 
@@ -88,6 +93,7 @@ public:
 
 private:
     freq_range_t _freq_range;
+    uhd::dict<std::string, gain_range_t> _rx_gain_ranges;
     uhd::dict<dboard_iface::unit_t, bool> _div2;
     double       _rx_lo_freq, _tx_lo_freq;
     std::string  _rx_ant;
@@ -166,6 +172,14 @@ rfx_xcvr::rfx_xcvr(
     _div2[dboard_iface::UNIT_RX] = rx_div2;
     _div2[dboard_iface::UNIT_TX] = tx_div2;
 
+    if(this->get_rx_id() == 0x0024) { //RFX400
+        _rx_gain_ranges = rfx400_rx_gain_ranges;
+    }
+    else {
+        _rx_gain_ranges = rfx_rx_gain_ranges;
+    }
+
+
     //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);
@@ -193,8 +207,8 @@ rfx_xcvr::rfx_xcvr(
     set_tx_lo_freq((_freq_range.min + _freq_range.max)/2.0);
     set_rx_ant("RX2");
 
-    BOOST_FOREACH(const std::string &name, rfx_rx_gain_ranges.keys()){
-        set_rx_gain(rfx_rx_gain_ranges[name].min, name);
+    BOOST_FOREACH(const std::string &name, _rx_gain_ranges.keys()){
+        set_rx_gain(_rx_gain_ranges[name].min, name);
     }
 }
 
@@ -227,10 +241,10 @@ void rfx_xcvr::set_tx_ant(const std::string &ant){
 /***********************************************************************
  * Gain Handling
  **********************************************************************/
-static float rx_pga0_gain_to_dac_volts(float &gain){
+static float rx_pga0_gain_to_dac_volts(float &gain, float range){
     //voltage level constants (negative slope)
     static const float max_volts = float(.2), min_volts = float(1.2);
-    static const float slope = (max_volts-min_volts)/45;
+    static const float slope = (max_volts-min_volts)/(range);
 
     //calculate the voltage for the aux dac
     float dac_volts = std::clip<float>(gain*slope + min_volts, max_volts, min_volts);
@@ -247,9 +261,10 @@ void rfx_xcvr::set_tx_gain(float, const std::string &name){
 }
 
 void rfx_xcvr::set_rx_gain(float gain, const std::string &name){
-    assert_has(rfx_rx_gain_ranges.keys(), name, "rfx rx gain name");
+    assert_has(_rx_gain_ranges.keys(), name, "rfx rx gain name");
     if(name == "PGA0"){
-        float dac_volts = rx_pga0_gain_to_dac_volts(gain);
+        float dac_volts = rx_pga0_gain_to_dac_volts(gain, 
+                              (_rx_gain_ranges["PGA0"].max - _rx_gain_ranges["PGA0"].min));
         _rx_gains[name] = gain;
 
         //write the new voltage to the aux dac
@@ -402,12 +417,12 @@ void rfx_xcvr::rx_get(const wax::obj &key_, wax::obj &val){
         return;
 
     case SUBDEV_PROP_GAIN_RANGE:
-        assert_has(rfx_rx_gain_ranges.keys(), name, "rfx rx gain name");
-        val = rfx_rx_gain_ranges[name];
+        assert_has(_rx_gain_ranges.keys(), name, "rfx rx gain name");
+        val = _rx_gain_ranges[name];
         return;
 
     case SUBDEV_PROP_GAIN_NAMES:
-        val = prop_names_t(rfx_rx_gain_ranges.keys());
+        val = prop_names_t(_rx_gain_ranges.keys());
         return;
 
     case SUBDEV_PROP_FREQ:
diff --git a/host/lib/usrp/mimo_usrp.cpp b/host/lib/usrp/mimo_usrp.cpp
index 6b9318c39..e78d38fc0 100644
--- a/host/lib/usrp/mimo_usrp.cpp
+++ b/host/lib/usrp/mimo_usrp.cpp
@@ -20,6 +20,7 @@
 #include <uhd/utils/assert.hpp>
 #include <uhd/utils/gain_group.hpp>
 #include <uhd/utils/algorithm.hpp>
+#include <uhd/utils/warning.hpp>
 #include <uhd/usrp/subdev_props.hpp>
 #include <uhd/usrp/mboard_props.hpp>
 #include <uhd/usrp/device_props.hpp>
@@ -47,31 +48,12 @@ public:
     mimo_usrp_impl(const device_addr_t &addr){
         _dev = device::make(addr);
 
-        //extract each mboard and its sub-devices
-        BOOST_FOREACH(const std::string &name, (*_dev)[DEVICE_PROP_MBOARD_NAMES].as<prop_names_t>()){
-            _mboards.push_back((*_dev)[named_prop_t(DEVICE_PROP_MBOARD, name)]);
-            _rx_dsps.push_back(_mboards.back()[MBOARD_PROP_RX_DSP]);
-            _tx_dsps.push_back(_mboards.back()[MBOARD_PROP_TX_DSP]);
-
-            //extract rx subdevice
-            _rx_dboards.push_back(_mboards.back()[MBOARD_PROP_RX_DBOARD]);
-            std::string rx_subdev_in_use = _rx_dboards.back()[DBOARD_PROP_USED_SUBDEVS].as<prop_names_t>().at(0);
-            _rx_subdevs.push_back(_rx_dboards.back()[named_prop_t(DBOARD_PROP_SUBDEV, rx_subdev_in_use)]);
-            _rx_gain_groups.push_back(_rx_dboards.back()[named_prop_t(DBOARD_PROP_GAIN_GROUP, rx_subdev_in_use)].as<gain_group::sptr>());
-
-            //extract tx subdevice
-            _tx_dboards.push_back(_mboards.back()[MBOARD_PROP_TX_DBOARD]);
-            std::string tx_subdev_in_use = _tx_dboards.back()[DBOARD_PROP_USED_SUBDEVS].as<prop_names_t>().at(0);
-            _tx_subdevs.push_back(_tx_dboards.back()[named_prop_t(DBOARD_PROP_SUBDEV, tx_subdev_in_use)]);
-            _tx_gain_groups.push_back(_tx_dboards.back()[named_prop_t(DBOARD_PROP_GAIN_GROUP, tx_subdev_in_use)].as<gain_group::sptr>());
-        }
-
         //set the clock config across all mboards (TODO set through api)
         clock_config_t clock_config;
         clock_config.ref_source = clock_config_t::REF_SMA;
         clock_config.pps_source = clock_config_t::PPS_SMA;
-        BOOST_FOREACH(wax::obj mboard, _mboards){
-            mboard[MBOARD_PROP_CLOCK_CONFIG] = clock_config;
+        for (size_t chan = 0; chan < get_num_channels(); chan++){
+            _mboard(chan)[MBOARD_PROP_CLOCK_CONFIG] = clock_config;
         }
     }
 
@@ -90,7 +72,7 @@ public:
         )
             % (*_dev)[DEVICE_PROP_NAME].as<std::string>()
         );
-        for (size_t i = 0; i < get_num_channels(); i++){
+        for (size_t chan = 0; chan < get_num_channels(); chan++){
             buff += str(boost::format(
                 "  Channel: %u\n"
                 "    Mboard: %s\n"
@@ -100,21 +82,21 @@ public:
                 "    TX DSP: %s\n"
                 "    TX Dboard: %s\n"
                 "    TX Subdev: %s\n"
-            ) % i
-                % _mboards.at(i)[MBOARD_PROP_NAME].as<std::string>()
-                % _rx_dsps.at(i)[DSP_PROP_NAME].as<std::string>()
-                % _rx_dboards.at(i)[DBOARD_PROP_NAME].as<std::string>()
-                % _rx_subdevs.at(i)[SUBDEV_PROP_NAME].as<std::string>()
-                % _tx_dsps.at(i)[DSP_PROP_NAME].as<std::string>()
-                % _tx_dboards.at(i)[DBOARD_PROP_NAME].as<std::string>()
-                % _tx_subdevs.at(i)[SUBDEV_PROP_NAME].as<std::string>()
+            ) % chan
+                % _mboard(chan)[MBOARD_PROP_NAME].as<std::string>()
+                % _rx_dsp(chan)[DSP_PROP_NAME].as<std::string>()
+                % _rx_dboard(chan)[DBOARD_PROP_NAME].as<std::string>()
+                % _rx_subdev(chan)[SUBDEV_PROP_NAME].as<std::string>()
+                % _tx_dsp(chan)[DSP_PROP_NAME].as<std::string>()
+                % _tx_dboard(chan)[DBOARD_PROP_NAME].as<std::string>()
+                % _tx_subdev(chan)[SUBDEV_PROP_NAME].as<std::string>()
             );
         }
         return buff;
     }
 
     size_t get_num_channels(void){
-        return _mboards.size();
+        return (*_dev)[DEVICE_PROP_MBOARD_NAMES].as<prop_names_t>().size();
     }
 
     /*******************************************************************
@@ -122,12 +104,12 @@ public:
      ******************************************************************/
     time_spec_t get_time_now(void){
         //the time on the first mboard better be the same on all
-        return _mboards.front()[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
+        return _mboard(0)[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
     }
 
     void set_time_next_pps(const time_spec_t &time_spec){
-        BOOST_FOREACH(wax::obj mboard, _mboards){
-            mboard[MBOARD_PROP_TIME_NEXT_PPS] = time_spec;
+        for (size_t chan = 0; chan < get_num_channels(); chan++){
+            _mboard(chan)[MBOARD_PROP_TIME_NEXT_PPS] = time_spec;
         }
     }
 
@@ -149,33 +131,42 @@ public:
         boost::this_thread::sleep(boost::posix_time::seconds(1));
 
         //verify that the time registers are read to be within a few RTT
-        for (size_t i = 1; i < get_num_channels(); i++){
-            time_spec_t time_0 = _mboards.front()[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
-            time_spec_t time_i = _mboards.at(i)[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
+        for (size_t chan = 1; chan < get_num_channels(); chan++){
+            time_spec_t time_0 = _mboard(0)[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
+            time_spec_t time_i = _mboard(chan)[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
             if (time_i < time_0 or (time_i - time_0) > time_spec_t(0.01)){ //10 ms: greater than RTT but not too big
-                std::cerr << boost::format(
-                    "Error: time deviation between board %d and board 0.\n"
-                    "    Board 0 time is %f seconds.\n"
-                    "    Board %d time is %f seconds.\n"
-                ) % i % time_0.get_real_secs() % i % time_i.get_real_secs() << std::endl;
+                uhd::print_warning(str(boost::format(
+                    "Detected time deviation between board %d and board 0.\n"
+                    "Board 0 time is %f seconds.\n"
+                    "Board %d time is %f seconds.\n"
+                ) % chan % time_0.get_real_secs() % chan % time_i.get_real_secs()));
             }
         }
     }
 
     void issue_stream_cmd(const stream_cmd_t &stream_cmd){
-        BOOST_FOREACH(wax::obj mboard, _mboards){
-            mboard[MBOARD_PROP_STREAM_CMD] = stream_cmd;
+        for (size_t chan = 0; chan < get_num_channels(); chan++){
+            _mboard(chan)[MBOARD_PROP_STREAM_CMD] = stream_cmd;
         }
     }
 
     /*******************************************************************
      * RX methods
      ******************************************************************/
+    void set_rx_subdev_spec(size_t chan, const subdev_spec_t &spec){
+        UHD_ASSERT_THROW(spec.size() <= 1);
+        _mboard(chan)[MBOARD_PROP_RX_SUBDEV_SPEC] = spec;
+    }
+
+    subdev_spec_t get_rx_subdev_spec(size_t chan){
+        return _mboard(chan)[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>();
+    }
+
     void set_rx_rate_all(double rate){
         std::vector<double> _actual_rates;
-        BOOST_FOREACH(wax::obj rx_dsp, _rx_dsps){
-            rx_dsp[DSP_PROP_HOST_RATE] = rate;
-            _actual_rates.push_back(rx_dsp[DSP_PROP_HOST_RATE].as<double>());
+        for (size_t chan = 0; chan < get_num_channels(); chan++){
+            _rx_dsp(chan)[DSP_PROP_HOST_RATE] = rate;
+            _actual_rates.push_back(_rx_dsp(chan)[DSP_PROP_HOST_RATE].as<double>());
         }
         _rx_rate = _actual_rates.front();
         if (std::count(_actual_rates, _rx_rate) != _actual_rates.size()) throw std::runtime_error(
@@ -188,61 +179,70 @@ public:
     }
 
     tune_result_t set_rx_freq(size_t chan, double target_freq){
-        return tune_rx_subdev_and_dsp(_rx_subdevs.at(chan), _rx_dsps.at(chan), target_freq);
+        return tune_rx_subdev_and_dsp(_rx_subdev(chan), _rx_dsp(chan), target_freq);
     }
 
     tune_result_t set_rx_freq(size_t chan, double target_freq, double lo_off){
-        return tune_rx_subdev_and_dsp(_rx_subdevs.at(chan), _rx_dsps.at(chan), target_freq, lo_off);
+        return tune_rx_subdev_and_dsp(_rx_subdev(chan), _rx_dsp(chan), target_freq, lo_off);
     }
 
     double get_rx_freq(size_t chan){
-        return derive_freq_from_rx_subdev_and_dsp(_rx_subdevs.at(chan), _rx_dsps.at(chan));
+        return derive_freq_from_rx_subdev_and_dsp(_rx_subdev(chan), _rx_dsp(chan));
     }
 
     freq_range_t get_rx_freq_range(size_t chan){
-        return add_dsp_shift(_rx_subdevs.at(chan)[SUBDEV_PROP_FREQ_RANGE].as<freq_range_t>(), _rx_dsps.at(chan));
+        return add_dsp_shift(_rx_subdev(chan)[SUBDEV_PROP_FREQ_RANGE].as<freq_range_t>(), _rx_dsp(chan));
     }
 
     void set_rx_gain(size_t chan, float gain){
-        _rx_gain_groups.at(chan)->set_value(gain);
+        return _rx_gain_group(chan)->set_value(gain);
     }
 
     float get_rx_gain(size_t chan){
-        return _rx_gain_groups.at(chan)->get_value();
+        return _rx_gain_group(chan)->get_value();
     }
 
     gain_range_t get_rx_gain_range(size_t chan){
-        return _rx_gain_groups.at(chan)->get_range();
+        return _rx_gain_group(chan)->get_range();
     }
 
     void set_rx_antenna(size_t chan, const std::string &ant){
-        _rx_subdevs.at(chan)[SUBDEV_PROP_ANTENNA] = ant;
+        _rx_subdev(chan)[SUBDEV_PROP_ANTENNA] = ant;
     }
 
     std::string get_rx_antenna(size_t chan){
-        return _rx_subdevs.at(chan)[SUBDEV_PROP_ANTENNA].as<std::string>();
+        return _rx_subdev(chan)[SUBDEV_PROP_ANTENNA].as<std::string>();
     }
 
     std::vector<std::string> get_rx_antennas(size_t chan){
-        return _rx_subdevs.at(chan)[SUBDEV_PROP_ANTENNA_NAMES].as<prop_names_t>();
+        return _rx_subdev(chan)[SUBDEV_PROP_ANTENNA_NAMES].as<prop_names_t>();
     }
 
     bool get_rx_lo_locked(size_t chan){
-        return _rx_subdevs.at(chan)[SUBDEV_PROP_LO_LOCKED].as<bool>();
+        return _rx_subdev(chan)[SUBDEV_PROP_LO_LOCKED].as<bool>();
     }
 
     float read_rssi(size_t chan){
-        return _rx_subdevs.at(chan)[SUBDEV_PROP_RSSI].as<float>();
+        return _rx_subdev(chan)[SUBDEV_PROP_RSSI].as<float>();
     }
 
     /*******************************************************************
      * TX methods
      ******************************************************************/
+    void set_tx_subdev_spec(size_t chan, const subdev_spec_t &spec){
+        UHD_ASSERT_THROW(spec.size() <= 1);
+        _mboard(chan)[MBOARD_PROP_TX_SUBDEV_SPEC] = spec;
+    }
+
+    subdev_spec_t get_tx_subdev_spec(size_t chan){
+        return _mboard(chan)[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>();
+    }
+
     void set_tx_rate_all(double rate){
         std::vector<double> _actual_rates;
-        BOOST_FOREACH(wax::obj tx_dsp, _tx_dsps){
-            tx_dsp[DSP_PROP_HOST_RATE] = rate;
-            _actual_rates.push_back(tx_dsp[DSP_PROP_HOST_RATE].as<double>());
+        for (size_t chan = 0; chan < get_num_channels(); chan++){
+            _tx_dsp(chan)[DSP_PROP_HOST_RATE] = rate;
+            _actual_rates.push_back(_tx_dsp(chan)[DSP_PROP_HOST_RATE].as<double>());
         }
         _tx_rate = _actual_rates.front();
         if (std::count(_actual_rates, _tx_rate) != _actual_rates.size()) throw std::runtime_error(
@@ -255,60 +255,85 @@ public:
     }
 
     tune_result_t set_tx_freq(size_t chan, double target_freq){
-        return tune_tx_subdev_and_dsp(_tx_subdevs.at(chan), _tx_dsps.at(chan), target_freq);
+        return tune_tx_subdev_and_dsp(_tx_subdev(chan), _tx_dsp(chan), target_freq);
     }
 
     tune_result_t set_tx_freq(size_t chan, double target_freq, double lo_off){
-        return tune_tx_subdev_and_dsp(_tx_subdevs.at(chan), _tx_dsps.at(chan), target_freq, lo_off);
+        return tune_tx_subdev_and_dsp(_tx_subdev(chan), _tx_dsp(chan), target_freq, lo_off);
     }
 
     double get_tx_freq(size_t chan){
-        return derive_freq_from_tx_subdev_and_dsp(_tx_subdevs.at(chan), _tx_dsps.at(chan));
+        return derive_freq_from_tx_subdev_and_dsp(_tx_subdev(chan), _tx_dsp(chan));
     }
 
     freq_range_t get_tx_freq_range(size_t chan){
-        return add_dsp_shift(_tx_subdevs.at(chan)[SUBDEV_PROP_FREQ_RANGE].as<freq_range_t>(), _tx_dsps.at(chan));
+        return add_dsp_shift(_tx_subdev(chan)[SUBDEV_PROP_FREQ_RANGE].as<freq_range_t>(), _tx_dsp(chan));
     }
 
     void set_tx_gain(size_t chan, float gain){
-        _tx_gain_groups.at(chan)->set_value(gain);
+        return _tx_gain_group(chan)->set_value(gain);
     }
 
     float get_tx_gain(size_t chan){
-        return _tx_gain_groups.at(chan)->get_value();
+        return _tx_gain_group(chan)->get_value();
     }
 
     gain_range_t get_tx_gain_range(size_t chan){
-        return _tx_gain_groups.at(chan)->get_range();
+        return _tx_gain_group(chan)->get_range();
     }
 
     void set_tx_antenna(size_t chan, const std::string &ant){
-        _tx_subdevs.at(chan)[SUBDEV_PROP_ANTENNA] = ant;
+        _tx_subdev(chan)[SUBDEV_PROP_ANTENNA] = ant;
     }
 
     std::string get_tx_antenna(size_t chan){
-        return _tx_subdevs.at(chan)[SUBDEV_PROP_ANTENNA].as<std::string>();
+        return _tx_subdev(chan)[SUBDEV_PROP_ANTENNA].as<std::string>();
     }
 
     std::vector<std::string> get_tx_antennas(size_t chan){
-        return _tx_subdevs.at(chan)[SUBDEV_PROP_ANTENNA_NAMES].as<prop_names_t>();
+        return _tx_subdev(chan)[SUBDEV_PROP_ANTENNA_NAMES].as<prop_names_t>();
     }
 
     bool get_tx_lo_locked(size_t chan){
-        return _tx_subdevs.at(chan)[SUBDEV_PROP_LO_LOCKED].as<bool>();
+        return _tx_subdev(chan)[SUBDEV_PROP_LO_LOCKED].as<bool>();
     }
 
 private:
     device::sptr _dev;
-    std::vector<wax::obj> _mboards;
-    std::vector<wax::obj> _rx_dsps;
-    std::vector<wax::obj> _tx_dsps;
-    std::vector<wax::obj> _rx_dboards;
-    std::vector<wax::obj> _tx_dboards;
-    std::vector<wax::obj> _rx_subdevs;
-    std::vector<wax::obj> _tx_subdevs;
-    std::vector<gain_group::sptr> _rx_gain_groups;
-    std::vector<gain_group::sptr> _tx_gain_groups;
+    wax::obj _mboard(size_t chan){
+        prop_names_t names = (*_dev)[DEVICE_PROP_MBOARD_NAMES].as<prop_names_t>();
+        return (*_dev)[named_prop_t(DEVICE_PROP_MBOARD, names.at(chan))];
+    }
+    wax::obj _rx_dsp(size_t chan){
+        return _mboard(chan)[MBOARD_PROP_RX_DSP];
+    }
+    wax::obj _tx_dsp(size_t chan){
+        return _mboard(chan)[MBOARD_PROP_TX_DSP];
+    }
+    wax::obj _rx_dboard(size_t chan){
+        std::string db_name = _mboard(chan)[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>().front().db_name;
+        return _mboard(chan)[named_prop_t(MBOARD_PROP_RX_DBOARD, db_name)];
+    }
+    wax::obj _tx_dboard(size_t chan){
+        std::string db_name = _mboard(chan)[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>().front().db_name;
+        return _mboard(chan)[named_prop_t(MBOARD_PROP_TX_DBOARD, db_name)];
+    }
+    wax::obj _rx_subdev(size_t chan){
+        std::string sd_name = _mboard(chan)[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>().front().sd_name;
+        return _rx_dboard(chan)[named_prop_t(DBOARD_PROP_SUBDEV, sd_name)];
+    }
+    wax::obj _tx_subdev(size_t chan){
+        std::string sd_name = _mboard(chan)[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>().front().sd_name;
+        return _tx_dboard(chan)[named_prop_t(DBOARD_PROP_SUBDEV, sd_name)];
+    }
+    gain_group::sptr _rx_gain_group(size_t chan){
+        std::string sd_name = _mboard(chan)[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>().front().sd_name;
+        return _rx_dboard(chan)[named_prop_t(DBOARD_PROP_GAIN_GROUP, sd_name)].as<gain_group::sptr>();
+    }
+    gain_group::sptr _tx_gain_group(size_t chan){
+        std::string sd_name = _mboard(chan)[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>().front().sd_name;
+        return _tx_dboard(chan)[named_prop_t(DBOARD_PROP_GAIN_GROUP, sd_name)].as<gain_group::sptr>();
+    }
 
     //shadows
     double _rx_rate, _tx_rate;
diff --git a/host/lib/usrp/simple_usrp.cpp b/host/lib/usrp/simple_usrp.cpp
index a8c20c439..5b4a58805 100644
--- a/host/lib/usrp/simple_usrp.cpp
+++ b/host/lib/usrp/simple_usrp.cpp
@@ -27,6 +27,7 @@
 #include <boost/foreach.hpp>
 #include <boost/format.hpp>
 #include <stdexcept>
+#include <iostream>
 
 using namespace uhd;
 using namespace uhd::usrp;
@@ -43,21 +44,6 @@ class simple_usrp_impl : public simple_usrp{
 public:
     simple_usrp_impl(const device_addr_t &addr){
         _dev = device::make(addr);
-        _mboard = (*_dev)[DEVICE_PROP_MBOARD];
-        _rx_dsp = _mboard[MBOARD_PROP_RX_DSP];
-        _tx_dsp = _mboard[MBOARD_PROP_TX_DSP];
-
-        //extract rx subdevice
-        _rx_dboard = _mboard[MBOARD_PROP_RX_DBOARD];
-        std::string rx_subdev_in_use = _rx_dboard[DBOARD_PROP_USED_SUBDEVS].as<prop_names_t>().at(0);
-        _rx_subdev = _rx_dboard[named_prop_t(DBOARD_PROP_SUBDEV, rx_subdev_in_use)];
-        _rx_gain_group = _rx_dboard[named_prop_t(DBOARD_PROP_GAIN_GROUP, rx_subdev_in_use)].as<gain_group::sptr>();
-
-        //extract tx subdevice
-        _tx_dboard = _mboard[MBOARD_PROP_TX_DBOARD];
-        std::string tx_subdev_in_use = _tx_dboard[DBOARD_PROP_USED_SUBDEVS].as<prop_names_t>().at(0);
-        _tx_subdev = _tx_dboard[named_prop_t(DBOARD_PROP_SUBDEV, tx_subdev_in_use)];
-        _tx_gain_group = _tx_dboard[named_prop_t(DBOARD_PROP_GAIN_GROUP, tx_subdev_in_use)].as<gain_group::sptr>();
     }
 
     ~simple_usrp_impl(void){
@@ -81,13 +67,13 @@ public:
             "  TX Subdev: %s\n"
         )
             % (*_dev)[DEVICE_PROP_NAME].as<std::string>()
-            % _mboard[MBOARD_PROP_NAME].as<std::string>()
-            % _rx_dsp[DSP_PROP_NAME].as<std::string>()
-            % _rx_dboard[DBOARD_PROP_NAME].as<std::string>()
-            % _rx_subdev[SUBDEV_PROP_NAME].as<std::string>()
-            % _tx_dsp[DSP_PROP_NAME].as<std::string>()
-            % _tx_dboard[DBOARD_PROP_NAME].as<std::string>()
-            % _tx_subdev[SUBDEV_PROP_NAME].as<std::string>()
+            % _mboard()[MBOARD_PROP_NAME].as<std::string>()
+            % _rx_dsp()[DSP_PROP_NAME].as<std::string>()
+            % _rx_dboard()[DBOARD_PROP_NAME].as<std::string>()
+            % _rx_subdev()[SUBDEV_PROP_NAME].as<std::string>()
+            % _tx_dsp()[DSP_PROP_NAME].as<std::string>()
+            % _tx_dboard()[DBOARD_PROP_NAME].as<std::string>()
+            % _tx_subdev()[SUBDEV_PROP_NAME].as<std::string>()
         );
     }
 
@@ -95,137 +81,155 @@ public:
      * Misc
      ******************************************************************/
     time_spec_t get_time_now(void){
-        return _mboard[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
+        return _mboard()[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
     }
 
     void set_time_now(const time_spec_t &time_spec){
-        _mboard[MBOARD_PROP_TIME_NOW] = time_spec;
+        _mboard()[MBOARD_PROP_TIME_NOW] = time_spec;
     }
 
     void set_time_next_pps(const time_spec_t &time_spec){
-        _mboard[MBOARD_PROP_TIME_NEXT_PPS] = time_spec;
+        _mboard()[MBOARD_PROP_TIME_NEXT_PPS] = time_spec;
     }
 
     void issue_stream_cmd(const stream_cmd_t &stream_cmd){
-        _mboard[MBOARD_PROP_STREAM_CMD] = stream_cmd;
+        _mboard()[MBOARD_PROP_STREAM_CMD] = stream_cmd;
     }
 
     void set_clock_config(const clock_config_t &clock_config){
-        _mboard[MBOARD_PROP_CLOCK_CONFIG] = clock_config;
+        _mboard()[MBOARD_PROP_CLOCK_CONFIG] = clock_config;
     }
 
     /*******************************************************************
      * RX methods
      ******************************************************************/
+    void set_rx_subdev_spec(const subdev_spec_t &spec){
+        _mboard()[MBOARD_PROP_RX_SUBDEV_SPEC] = spec;
+        std::cout << "RX " << _mboard()[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>().to_pp_string() << std::endl;
+    }
+
+    subdev_spec_t get_rx_subdev_spec(void){
+        return _mboard()[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>();
+    }
+
     void set_rx_rate(double rate){
-        _rx_dsp[DSP_PROP_HOST_RATE] = rate;
+        _rx_dsp()[DSP_PROP_HOST_RATE] = rate;
     }
 
     double get_rx_rate(void){
-        return _rx_dsp[DSP_PROP_HOST_RATE].as<double>();
+        return _rx_dsp()[DSP_PROP_HOST_RATE].as<double>();
     }
 
     tune_result_t set_rx_freq(double target_freq){
-        return tune_rx_subdev_and_dsp(_rx_subdev, _rx_dsp, target_freq);
+        return tune_rx_subdev_and_dsp(_rx_subdev(), _rx_dsp(), target_freq);
     }
 
     tune_result_t set_rx_freq(double target_freq, double lo_off){
-        return tune_rx_subdev_and_dsp(_rx_subdev, _rx_dsp, target_freq, lo_off);
+        return tune_rx_subdev_and_dsp(_rx_subdev(), _rx_dsp(), target_freq, lo_off);
     }
 
     double get_rx_freq(void){
-        return derive_freq_from_rx_subdev_and_dsp(_rx_subdev, _rx_dsp);
+        return derive_freq_from_rx_subdev_and_dsp(_rx_subdev(), _rx_dsp());
     }
 
     freq_range_t get_rx_freq_range(void){
-        return add_dsp_shift(_rx_subdev[SUBDEV_PROP_FREQ_RANGE].as<freq_range_t>(), _rx_dsp);
+        return add_dsp_shift(_rx_subdev()[SUBDEV_PROP_FREQ_RANGE].as<freq_range_t>(), _rx_dsp());
     }
 
     void set_rx_gain(float gain){
-        _rx_gain_group->set_value(gain);
+        return _rx_gain_group()->set_value(gain);
     }
 
     float get_rx_gain(void){
-        return _rx_gain_group->get_value();
+        return _rx_gain_group()->get_value();
     }
 
     gain_range_t get_rx_gain_range(void){
-        return _rx_gain_group->get_range();
+        return _rx_gain_group()->get_range();
     }
 
     void set_rx_antenna(const std::string &ant){
-        _rx_subdev[SUBDEV_PROP_ANTENNA] = ant;
+        _rx_subdev()[SUBDEV_PROP_ANTENNA] = ant;
     }
 
     std::string get_rx_antenna(void){
-        return _rx_subdev[SUBDEV_PROP_ANTENNA].as<std::string>();
+        return _rx_subdev()[SUBDEV_PROP_ANTENNA].as<std::string>();
     }
 
     std::vector<std::string> get_rx_antennas(void){
-        return _rx_subdev[SUBDEV_PROP_ANTENNA_NAMES].as<prop_names_t>();
+        return _rx_subdev()[SUBDEV_PROP_ANTENNA_NAMES].as<prop_names_t>();
     }
 
     bool get_rx_lo_locked(void){
-        return _rx_subdev[SUBDEV_PROP_LO_LOCKED].as<bool>();
+        return _rx_subdev()[SUBDEV_PROP_LO_LOCKED].as<bool>();
     }
 
     float read_rssi(void){
-        return _rx_subdev[SUBDEV_PROP_RSSI].as<float>();
+        return _rx_subdev()[SUBDEV_PROP_RSSI].as<float>();
     }
 
     /*******************************************************************
      * TX methods
      ******************************************************************/
+    void set_tx_subdev_spec(const subdev_spec_t &spec){
+        _mboard()[MBOARD_PROP_TX_SUBDEV_SPEC] = spec;
+        std::cout << "TX " << _mboard()[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>().to_pp_string() << std::endl;
+    }
+
+    subdev_spec_t get_tx_subdev_spec(void){
+        return _mboard()[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>();
+    }
+
     void set_tx_rate(double rate){
-        _tx_dsp[DSP_PROP_HOST_RATE] = rate;
+        _tx_dsp()[DSP_PROP_HOST_RATE] = rate;
     }
 
     double get_tx_rate(void){
-        return _tx_dsp[DSP_PROP_HOST_RATE].as<double>();
+        return _tx_dsp()[DSP_PROP_HOST_RATE].as<double>();
     }
 
     tune_result_t set_tx_freq(double target_freq){
-        return tune_tx_subdev_and_dsp(_tx_subdev, _tx_dsp, target_freq);
+        return tune_tx_subdev_and_dsp(_tx_subdev(), _tx_dsp(), target_freq);
     }
 
     tune_result_t set_tx_freq(double target_freq, double lo_off){
-        return tune_tx_subdev_and_dsp(_tx_subdev, _tx_dsp, target_freq, lo_off);
+        return tune_tx_subdev_and_dsp(_tx_subdev(), _tx_dsp(), target_freq, lo_off);
     }
 
     double get_tx_freq(void){
-        return derive_freq_from_tx_subdev_and_dsp(_tx_subdev, _tx_dsp);
+        return derive_freq_from_tx_subdev_and_dsp(_tx_subdev(), _tx_dsp());
     }
 
     freq_range_t get_tx_freq_range(void){
-        return add_dsp_shift(_tx_subdev[SUBDEV_PROP_FREQ_RANGE].as<freq_range_t>(), _tx_dsp);
+        return add_dsp_shift(_tx_subdev()[SUBDEV_PROP_FREQ_RANGE].as<freq_range_t>(), _tx_dsp());
     }
 
     void set_tx_gain(float gain){
-        _tx_gain_group->set_value(gain);
+        return _tx_gain_group()->set_value(gain);
     }
 
     float get_tx_gain(void){
-        return _tx_gain_group->get_value();
+        return _tx_gain_group()->get_value();
     }
 
     gain_range_t get_tx_gain_range(void){
-        return _tx_gain_group->get_range();
+        return _tx_gain_group()->get_range();
     }
 
     void set_tx_antenna(const std::string &ant){
-        _tx_subdev[SUBDEV_PROP_ANTENNA] = ant;
+        _tx_subdev()[SUBDEV_PROP_ANTENNA] = ant;
     }
 
     std::string get_tx_antenna(void){
-        return _tx_subdev[SUBDEV_PROP_ANTENNA].as<std::string>();
+        return _tx_subdev()[SUBDEV_PROP_ANTENNA].as<std::string>();
     }
 
     std::vector<std::string> get_tx_antennas(void){
-        return _tx_subdev[SUBDEV_PROP_ANTENNA_NAMES].as<prop_names_t>();
+        return _tx_subdev()[SUBDEV_PROP_ANTENNA_NAMES].as<prop_names_t>();
     }
 
     bool get_tx_lo_locked(void){
-        return _tx_subdev[SUBDEV_PROP_LO_LOCKED].as<bool>();
+        return _tx_subdev()[SUBDEV_PROP_LO_LOCKED].as<bool>();
     }
 
     /*******************************************************************
@@ -233,24 +237,48 @@ public:
      ******************************************************************/
 
     wax::obj get_rx_dboard_iface(void) {
-        return _rx_dboard;
+        return _rx_dboard();
     }
 
     wax::obj get_tx_dboard_iface(void) {
-        return _tx_dboard;
+        return _tx_dboard();
     }
 
 private:
     device::sptr _dev;
-    wax::obj _mboard;
-    wax::obj _rx_dsp;
-    wax::obj _tx_dsp;
-    wax::obj _rx_dboard;
-    wax::obj _tx_dboard;
-    wax::obj _rx_subdev;
-    wax::obj _tx_subdev;
-    gain_group::sptr _rx_gain_group;
-    gain_group::sptr _tx_gain_group;
+    wax::obj _mboard(void){
+        return (*_dev)[DEVICE_PROP_MBOARD];
+    }
+    wax::obj _rx_dsp(void){
+        return _mboard()[MBOARD_PROP_RX_DSP];
+    }
+    wax::obj _tx_dsp(void){
+        return _mboard()[MBOARD_PROP_TX_DSP];
+    }
+    wax::obj _rx_dboard(void){
+        std::string db_name = _mboard()[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>().front().db_name;
+        return _mboard()[named_prop_t(MBOARD_PROP_RX_DBOARD, db_name)];
+    }
+    wax::obj _tx_dboard(void){
+        std::string db_name = _mboard()[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>().front().db_name;
+        return _mboard()[named_prop_t(MBOARD_PROP_TX_DBOARD, db_name)];
+    }
+    wax::obj _rx_subdev(void){
+        std::string sd_name = _mboard()[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>().front().sd_name;
+        return _rx_dboard()[named_prop_t(DBOARD_PROP_SUBDEV, sd_name)];
+    }
+    wax::obj _tx_subdev(void){
+        std::string sd_name = _mboard()[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>().front().sd_name;
+        return _tx_dboard()[named_prop_t(DBOARD_PROP_SUBDEV, sd_name)];
+    }
+    gain_group::sptr _rx_gain_group(void){
+        std::string sd_name = _mboard()[MBOARD_PROP_RX_SUBDEV_SPEC].as<subdev_spec_t>().front().sd_name;
+        return _rx_dboard()[named_prop_t(DBOARD_PROP_GAIN_GROUP, sd_name)].as<gain_group::sptr>();
+    }
+    gain_group::sptr _tx_gain_group(void){
+        std::string sd_name = _mboard()[MBOARD_PROP_TX_SUBDEV_SPEC].as<subdev_spec_t>().front().sd_name;
+        return _tx_dboard()[named_prop_t(DBOARD_PROP_GAIN_GROUP, sd_name)].as<gain_group::sptr>();
+    }
 };
 
 /***********************************************************************
diff --git a/host/lib/usrp/subdev_spec.cpp b/host/lib/usrp/subdev_spec.cpp
new file mode 100644
index 000000000..0f00e2f74
--- /dev/null
+++ b/host/lib/usrp/subdev_spec.cpp
@@ -0,0 +1,77 @@
+//
+// Copyright 2010 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 <uhd/usrp/subdev_spec.hpp>
+#include <boost/algorithm/string.hpp>
+#include <boost/format.hpp>
+#include <boost/foreach.hpp>
+#include <stdexcept>
+#include <sstream>
+
+using namespace uhd;
+using namespace uhd::usrp;
+
+subdev_spec_pair_t::subdev_spec_pair_t(
+    const std::string &db_name, const std::string &sd_name
+):
+    db_name(db_name),
+    sd_name(sd_name)
+{
+    /* NOP */
+}
+
+subdev_spec_t::subdev_spec_t(const std::string &markup){
+    std::vector<std::string> pairs;
+    boost::split(pairs, markup, boost::is_any_of("\t "));
+    BOOST_FOREACH(const std::string &pair, pairs){
+        if (pair == "") continue;
+        std::vector<std::string> db_sd;
+        boost::split(db_sd, pair, boost::is_any_of(":"));
+        switch(db_sd.size()){
+        case 1: this->push_back(subdev_spec_pair_t("", db_sd.front())); break;
+        case 2: this->push_back(subdev_spec_pair_t(db_sd.front(), db_sd.back())); break;
+        default: throw std::runtime_error("invalid subdev-spec markup string: "+markup);
+        }
+    }
+}
+
+std::string subdev_spec_t::to_pp_string(void) const{
+    if (this->size() == 0) return "Empty Subdevice Specification";
+
+    std::stringstream ss;
+    size_t count = 0;
+    ss << "Subdevice Specification:" << std::endl;
+    BOOST_FOREACH(const subdev_spec_pair_t &pair, *this){
+        std::string db_name = pair.db_name;
+        if (db_name == "") db_name = "0";
+        std::string sd_name = pair.sd_name;
+        if (sd_name == "") sd_name = "0";
+        ss << boost::format(
+            "    Channel %d: Daughterboard %s, Subdevice %s"
+        ) % (count++) % db_name % sd_name << std::endl;
+    }
+    return ss.str();
+}
+
+std::string subdev_spec_t::to_string(void) const{
+    std::string markup;
+    size_t count = 0;
+    BOOST_FOREACH(const subdev_spec_pair_t &pair, *this){
+        markup += ((count++)? " " : "") + pair.db_name + ":" + pair.sd_name;
+    }
+    return markup;
+}
diff --git a/host/lib/usrp/usrp2/clock_ctrl.cpp b/host/lib/usrp/usrp2/clock_ctrl.cpp
index 5ed8ec079..ef027c1df 100644
--- a/host/lib/usrp/usrp2/clock_ctrl.cpp
+++ b/host/lib/usrp/usrp2/clock_ctrl.cpp
@@ -90,7 +90,7 @@ public:
 
     void set_rate_rx_dboard_clock(double rate){
         assert_has(get_rates_rx_dboard_clock(), rate, "rx dboard clock rate");
-        size_t divider = size_t(rate/get_master_clock_rate());
+        size_t divider = size_t(get_master_clock_rate()/rate);
         //bypass when the divider ratio is one
         _ad9510_regs.bypass_divider_out7 = (divider == 1)? 1 : 0;
         //calculate the low and high dividers
@@ -132,7 +132,9 @@ public:
 
     void set_rate_tx_dboard_clock(double rate){
         assert_has(get_rates_tx_dboard_clock(), rate, "tx dboard clock rate");
-        size_t divider = size_t(rate/get_master_clock_rate());
+        size_t divider = size_t(get_master_clock_rate()/rate);
+        //bypass when the divider ratio is one
+        _ad9510_regs.bypass_divider_out6 = (divider == 1)? 1 : 0;
         //calculate the low and high dividers
         size_t high = divider/2;
         size_t low = divider - high;
diff --git a/host/lib/usrp/usrp2/dboard_iface.cpp b/host/lib/usrp/usrp2/dboard_iface.cpp
index 5c81856bb..be45c2c9e 100644
--- a/host/lib/usrp/usrp2/dboard_iface.cpp
+++ b/host/lib/usrp/usrp2/dboard_iface.cpp
@@ -37,6 +37,8 @@ public:
     usrp2_dboard_iface(usrp2_iface::sptr iface, usrp2_clock_ctrl::sptr clock_ctrl);
     ~usrp2_dboard_iface(void);
 
+    std::string get_mboard_name(void){return "usrp2";}
+
     void write_aux_dac(unit_t, aux_dac_t, float);
     float read_aux_adc(unit_t, aux_adc_t);
 
diff --git a/host/lib/usrp/usrp2/dboard_impl.cpp b/host/lib/usrp/usrp2/dboard_impl.cpp
index 3a2a53674..075f22388 100644
--- a/host/lib/usrp/usrp2/dboard_impl.cpp
+++ b/host/lib/usrp/usrp2/dboard_impl.cpp
@@ -53,10 +53,6 @@ void usrp2_mboard_impl::dboard_init(void){
         boost::bind(&usrp2_mboard_impl::tx_dboard_get, this, _1, _2),
         boost::bind(&usrp2_mboard_impl::tx_dboard_set, this, _1, _2)
     );
-
-    //init the subdevs in use (use the first subdevice)
-    rx_dboard_set(DBOARD_PROP_USED_SUBDEVS, prop_names_t(1, _dboard_manager->get_rx_subdev_names().at(0)));
-    tx_dboard_set(DBOARD_PROP_USED_SUBDEVS, prop_names_t(1, _dboard_manager->get_tx_subdev_names().at(0)));
 }
 
 /***********************************************************************
@@ -80,10 +76,6 @@ void usrp2_mboard_impl::rx_dboard_get(const wax::obj &key_, wax::obj &val){
         val = _dboard_manager->get_rx_subdev_names();
         return;
 
-    case DBOARD_PROP_USED_SUBDEVS:
-        val = _rx_subdevs_in_use;
-        return;
-
     case DBOARD_PROP_DBOARD_ID:
         val = _rx_db_eeprom.id;
         return;
@@ -108,16 +100,6 @@ void usrp2_mboard_impl::rx_dboard_get(const wax::obj &key_, wax::obj &val){
 
 void usrp2_mboard_impl::rx_dboard_set(const wax::obj &key, const wax::obj &val){
     switch(key.as<dboard_prop_t>()){
-    case DBOARD_PROP_USED_SUBDEVS:{
-            _rx_subdevs_in_use = val.as<prop_names_t>();
-            UHD_ASSERT_THROW(_rx_subdevs_in_use.size() == 1);
-            wax::obj rx_subdev = _dboard_manager->get_rx_subdev(_rx_subdevs_in_use.at(0));
-            std::cout << "Using: " << rx_subdev[SUBDEV_PROP_NAME].as<std::string>() << std::endl;
-            _iface->poke32(_iface->regs.dsp_rx_mux, dsp_type1::calc_rx_mux_word(
-                rx_subdev[SUBDEV_PROP_CONNECTION].as<subdev_conn_t>()
-            ));
-        }
-        return;
 
     case DBOARD_PROP_DBOARD_ID:
         _rx_db_eeprom.id = val.as<dboard_id_t>();
@@ -149,10 +131,6 @@ void usrp2_mboard_impl::tx_dboard_get(const wax::obj &key_, wax::obj &val){
         val = _dboard_manager->get_tx_subdev_names();
         return;
 
-    case DBOARD_PROP_USED_SUBDEVS:
-        val = _tx_subdevs_in_use;
-        return;
-
     case DBOARD_PROP_DBOARD_ID:
         val = _tx_db_eeprom.id;
         return;
@@ -177,16 +155,6 @@ void usrp2_mboard_impl::tx_dboard_get(const wax::obj &key_, wax::obj &val){
 
 void usrp2_mboard_impl::tx_dboard_set(const wax::obj &key, const wax::obj &val){
     switch(key.as<dboard_prop_t>()){
-    case DBOARD_PROP_USED_SUBDEVS:{
-            _tx_subdevs_in_use = val.as<prop_names_t>();
-            UHD_ASSERT_THROW(_tx_subdevs_in_use.size() == 1);
-            wax::obj tx_subdev = _dboard_manager->get_tx_subdev(_tx_subdevs_in_use.at(0));
-            std::cout << "Using: " << tx_subdev[SUBDEV_PROP_NAME].as<std::string>() << std::endl;
-            _iface->poke32(_iface->regs.dsp_tx_mux, dsp_type1::calc_tx_mux_word(
-                tx_subdev[SUBDEV_PROP_CONNECTION].as<subdev_conn_t>()
-            ));
-        }
-        return;
 
     case DBOARD_PROP_DBOARD_ID:
         _tx_db_eeprom.id = val.as<dboard_id_t>();
diff --git a/host/lib/usrp/usrp2/fw_common.h b/host/lib/usrp/usrp2/fw_common.h
index 389ac9892..85d41d57f 100644
--- a/host/lib/usrp/usrp2/fw_common.h
+++ b/host/lib/usrp/usrp2/fw_common.h
@@ -32,9 +32,9 @@ extern "C" {
     #define __stdint(type) type
 #endif
 
-//defines the protocol version in this shared header
-//increment this value when the protocol is changed
-#define USRP2_PROTO_VERSION 5
+//fpga and firmware compatibility numbers
+#define USRP2_FPGA_COMPAT_NUM 1
+#define USRP2_FW_COMPAT_NUM 5
 
 //used to differentiate control packets over data port
 #define USRP2_INVALID_VRT_HEADER 0
diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
index aa6d15783..c67bd02fd 100644
--- a/host/lib/usrp/usrp2/io_impl.cpp
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -144,11 +144,13 @@ void usrp2_impl::io_impl::recv_pirate_loop(
  **********************************************************************/
 void usrp2_impl::io_init(void){
     //send a small data packet so the usrp2 knows the udp source port
-    for(size_t i = 0; i < _data_transports.size(); i++){
-        managed_send_buffer::sptr send_buff = _data_transports[i]->get_send_buff();
-        boost::uint32_t data = htonl(USRP2_INVALID_VRT_HEADER);
-        memcpy(send_buff->cast<void*>(), &data, sizeof(data));
+    BOOST_FOREACH(zero_copy_if::sptr data_transport, _data_transports){
+        managed_send_buffer::sptr send_buff = data_transport->get_send_buff();
+        static const boost::uint32_t data = htonl(USRP2_INVALID_VRT_HEADER);
+        std::memcpy(send_buff->cast<void*>(), &data, sizeof(data));
         send_buff->commit(sizeof(data));
+        //drain the recv buffers (may have junk)
+        while (data_transport->get_recv_buff().get()){;}
     }
 
     //the number of recv frames is the number for the first transport
diff --git a/host/lib/usrp/usrp2/mboard_impl.cpp b/host/lib/usrp/usrp2/mboard_impl.cpp
index c8e22a709..a3d5e8955 100644
--- a/host/lib/usrp/usrp2/mboard_impl.cpp
+++ b/host/lib/usrp/usrp2/mboard_impl.cpp
@@ -105,6 +105,15 @@ usrp2_mboard_impl::usrp2_mboard_impl(
 
     //init the tx and rx dboards (do last)
     dboard_init();
+
+    //set default subdev specs
+    (*this)[MBOARD_PROP_RX_SUBDEV_SPEC] = subdev_spec_t();
+    (*this)[MBOARD_PROP_TX_SUBDEV_SPEC] = subdev_spec_t();
+
+    //Issue a stop streaming command (in case it was left running).
+    //Since this command is issued before the networking is setup,
+    //most if not all junk packets will never make it to the socket.
+    this->issue_ddc_stream_cmd(stream_cmd_t::STREAM_MODE_STOP_CONTINUOUS);
 }
 
 usrp2_mboard_impl::~usrp2_mboard_impl(void){
@@ -265,6 +274,14 @@ void usrp2_mboard_impl::get(const wax::obj &key_, wax::obj &val){
         }
         return;
 
+    case MBOARD_PROP_RX_SUBDEV_SPEC:
+        val = _rx_subdev_spec;
+        return;
+
+    case MBOARD_PROP_TX_SUBDEV_SPEC:
+        val = _tx_subdev_spec;
+        return;
+
     default: UHD_THROW_PROP_GET_ERROR();
     }
 }
@@ -309,6 +326,38 @@ void usrp2_mboard_impl::set(const wax::obj &key, const wax::obj &val){
         issue_ddc_stream_cmd(val.as<stream_cmd_t>());
         return;
 
+    case MBOARD_PROP_RX_SUBDEV_SPEC:
+        _rx_subdev_spec = val.as<subdev_spec_t>();
+        //handle automatic
+        if (_rx_subdev_spec.empty()) _rx_subdev_spec.push_back(
+            subdev_spec_pair_t("", _dboard_manager->get_rx_subdev_names().front())
+        );
+        //sanity check
+        UHD_ASSERT_THROW(_rx_subdev_spec.size() == 1);
+        uhd::assert_has((*this)[MBOARD_PROP_RX_DBOARD_NAMES].as<prop_names_t>(), _rx_subdev_spec.front().db_name, "rx dboard names");
+        uhd::assert_has(_dboard_manager->get_rx_subdev_names(), _rx_subdev_spec.front().sd_name, "rx subdev names");
+        //set the mux
+        _iface->poke32(_iface->regs.dsp_rx_mux, dsp_type1::calc_rx_mux_word(
+            _dboard_manager->get_rx_subdev(_rx_subdev_spec.front().sd_name)[SUBDEV_PROP_CONNECTION].as<subdev_conn_t>()
+        ));
+        return;
+
+    case MBOARD_PROP_TX_SUBDEV_SPEC:
+        _tx_subdev_spec = val.as<subdev_spec_t>();
+        //handle automatic
+        if (_tx_subdev_spec.empty()) _tx_subdev_spec.push_back(
+            subdev_spec_pair_t("", _dboard_manager->get_tx_subdev_names().front())
+        );
+        //sanity check
+        UHD_ASSERT_THROW(_tx_subdev_spec.size() == 1);
+        uhd::assert_has((*this)[MBOARD_PROP_TX_DBOARD_NAMES].as<prop_names_t>(), _tx_subdev_spec.front().db_name, "tx dboard names");
+        uhd::assert_has(_dboard_manager->get_tx_subdev_names(), _tx_subdev_spec.front().sd_name, "tx subdev names");
+        //set the mux
+        _iface->poke32(_iface->regs.dsp_tx_mux, dsp_type1::calc_tx_mux_word(
+            _dboard_manager->get_tx_subdev(_tx_subdev_spec.front().sd_name)[SUBDEV_PROP_CONNECTION].as<subdev_conn_t>()
+        ));
+        return;
+
     default: UHD_THROW_PROP_SET_ERROR();
     }
 }
diff --git a/host/lib/usrp/usrp2/usrp2_iface.cpp b/host/lib/usrp/usrp2/usrp2_iface.cpp
index 2a380dc44..44aef2a34 100644
--- a/host/lib/usrp/usrp2/usrp2_iface.cpp
+++ b/host/lib/usrp/usrp2/usrp2_iface.cpp
@@ -15,6 +15,7 @@
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //
 
+#include "usrp2_regs.hpp"
 #include "usrp2_iface.hpp"
 #include <uhd/utils/assert.hpp>
 #include <uhd/types/dict.hpp>
@@ -22,6 +23,7 @@
 #include <boost/foreach.hpp>
 #include <boost/asio.hpp> //used for htonl and ntohl
 #include <boost/assign/list_of.hpp>
+#include <boost/format.hpp>
 #include <stdexcept>
 #include <algorithm>
 
@@ -47,6 +49,15 @@ public:
  **********************************************************************/
     usrp2_iface_impl(udp_simple::sptr ctrl_transport){
         _ctrl_transport = ctrl_transport;
+
+         //check the fpga compatibility number
+        const boost::uint32_t fpga_compat_num = this->peek32(this->regs.compat_num_rb);
+        if (fpga_compat_num != USRP2_FPGA_COMPAT_NUM){
+            throw std::runtime_error(str(boost::format(
+                "Expected fpga compatibility number %d, but got %d:\n"
+                "The fpga build is not compatible with the host code build."
+            ) % int(USRP2_FPGA_COMPAT_NUM) % fpga_compat_num));
+        }
     }
 
     ~usrp2_iface_impl(void){
@@ -168,7 +179,7 @@ public:
 
         //fill in the seq number and send
         usrp2_ctrl_data_t out_copy = out_data;
-        out_copy.proto_ver = htonl(USRP2_PROTO_VERSION);
+        out_copy.proto_ver = htonl(USRP2_FW_COMPAT_NUM);
         out_copy.seq = htonl(++_ctrl_seq_num);
         _ctrl_transport->send(boost::asio::buffer(&out_copy, sizeof(usrp2_ctrl_data_t)));
 
@@ -177,12 +188,11 @@ public:
         const usrp2_ctrl_data_t *ctrl_data_in = reinterpret_cast<const usrp2_ctrl_data_t *>(usrp2_ctrl_data_in_mem);
         while(true){
             size_t len = _ctrl_transport->recv(boost::asio::buffer(usrp2_ctrl_data_in_mem), CONTROL_TIMEOUT_MS);
-            if(len >= sizeof(boost::uint32_t) and ntohl(ctrl_data_in->proto_ver) != USRP2_PROTO_VERSION){
-                throw std::runtime_error(str(
-                    boost::format("Expected protocol version %d, but got %d\n"
-                    "The firmware build does not match the host code build."
-                    ) % int(USRP2_PROTO_VERSION) % ntohl(ctrl_data_in->proto_ver)
-                ));
+            if(len >= sizeof(boost::uint32_t) and ntohl(ctrl_data_in->proto_ver) != USRP2_FW_COMPAT_NUM){
+                throw std::runtime_error(str(boost::format(
+                    "Expected protocol compatibility number %d, but got %d:\n"
+                    "The firmware build is not compatible with the host code build."
+                ) % int(USRP2_FW_COMPAT_NUM) % ntohl(ctrl_data_in->proto_ver)));
             }
             if (len >= sizeof(usrp2_ctrl_data_t) and ntohl(ctrl_data_in->seq) == _ctrl_seq_num){
                 return *ctrl_data_in;
diff --git a/host/lib/usrp/usrp2/usrp2_impl.cpp b/host/lib/usrp/usrp2/usrp2_impl.cpp
index 2c314c085..21f411afe 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.cpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.cpp
@@ -97,7 +97,7 @@ static uhd::device_addrs_t usrp2_find(const device_addr_t &hint){
 
     //send a hello control packet
     usrp2_ctrl_data_t ctrl_data_out;
-    ctrl_data_out.proto_ver = htonl(USRP2_PROTO_VERSION);
+    ctrl_data_out.proto_ver = htonl(USRP2_FW_COMPAT_NUM);
     ctrl_data_out.id = htonl(USRP2_CTRL_ID_WAZZUP_BRO);
     udp_transport->send(boost::asio::buffer(&ctrl_data_out, sizeof(ctrl_data_out)));
 
diff --git a/host/lib/usrp/usrp2/usrp2_impl.hpp b/host/lib/usrp/usrp2/usrp2_impl.hpp
index 8421b6b39..21a56cb67 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.hpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.hpp
@@ -35,6 +35,7 @@
 #include <uhd/transport/udp_simple.hpp> //mtu
 #include <uhd/transport/udp_zero_copy.hpp>
 #include <uhd/usrp/dboard_manager.hpp>
+#include <uhd/usrp/subdev_spec.hpp>
 
 /*!
  * Make a usrp2 dboard interface.
@@ -143,6 +144,7 @@ private:
     //properties for this mboard
     void get(const wax::obj &, wax::obj &);
     void set(const wax::obj &, const wax::obj &);
+    uhd::usrp::subdev_spec_t _rx_subdev_spec, _tx_subdev_spec;
 
     //interfaces
     usrp2_iface::sptr _iface;
@@ -177,14 +179,12 @@ private:
     void rx_dboard_get(const wax::obj &, wax::obj &);
     void rx_dboard_set(const wax::obj &, const wax::obj &);
     wax_obj_proxy::sptr _rx_dboard_proxy;
-    uhd::prop_names_t _rx_subdevs_in_use;
     uhd::usrp::dboard_eeprom_t _rx_db_eeprom;
 
     //properties interface for tx dboard
     void tx_dboard_get(const wax::obj &, wax::obj &);
     void tx_dboard_set(const wax::obj &, const wax::obj &);
     wax_obj_proxy::sptr _tx_dboard_proxy;
-    uhd::prop_names_t _tx_subdevs_in_use;
     uhd::usrp::dboard_eeprom_t _tx_db_eeprom;
 
     //methods and shadows for the ddc dsp
diff --git a/host/lib/usrp/usrp2/usrp2_regs.cpp b/host/lib/usrp/usrp2/usrp2_regs.cpp
index 857fbda9c..49f077221 100644
--- a/host/lib/usrp/usrp2/usrp2_regs.cpp
+++ b/host/lib/usrp/usrp2/usrp2_regs.cpp
@@ -58,6 +58,7 @@ usrp2_regs_t usrp2_get_regs(int hw_rev) {
   x.time64_tps = sr_addr(misc_output_base, x.sr_time64 + 4);
   x.time64_secs_rb = bp_base + 4*10;
   x.time64_ticks_rb = bp_base + 4*11;
+  x.compat_num_rb = bp_base + 4*12;
   x.dsp_tx_freq = sr_addr(misc_output_base, x.sr_tx_dsp + 0);
   x.dsp_tx_scale_iq = sr_addr(misc_output_base, x.sr_tx_dsp + 1);
   x.dsp_tx_interp_rate = sr_addr(misc_output_base, x.sr_tx_dsp + 2);
diff --git a/host/lib/usrp/usrp2/usrp2_regs.hpp b/host/lib/usrp/usrp2/usrp2_regs.hpp
index c12098c8e..0a171d20c 100644
--- a/host/lib/usrp/usrp2/usrp2_regs.hpp
+++ b/host/lib/usrp/usrp2/usrp2_regs.hpp
@@ -61,6 +61,7 @@ typedef struct {
 	int time64_tps; // ticks per second rollover count
 	int time64_secs_rb;
 	int time64_ticks_rb;
+  int compat_num_rb;
 	int dsp_tx_freq;
 	int dsp_tx_scale_iq;
 	int dsp_tx_interp_rate;