uhd

    size_t index,

    transport::udp_simple::sptr ctrl_transport,

    transport::zero_copy_if::sptr data_transport,

):

    _index(index),

    _iface(usrp2_iface::make(ctrl_transport))

    //contruct the interfaces to mboard perifs

    _clock_ctrl = usrp2_clock_ctrl::make(_iface);

    _codec_ctrl = usrp2_codec_ctrl::make(_iface);

    //_gps_ctrl = usrp2_gps_ctrl::make(_iface);

    //if(_gps_ctrl->gps_detected()) std::cout << "GPS time: " << _gps_ctrl->get_time() << std::endl;

    _iface->poke32(_iface->regs.tx_ctrl_policy, U2_FLAG_TX_CTRL_POLICY_NEXT_PACKET);

    //setting the cycles per update (disabled by default)

    if (ups_per_sec > 0.0){

        const size_t cycles_per_up = size_t(_clock_ctrl->get_master_clock_rate()/ups_per_sec);

        _iface->poke32(_iface->regs.tx_ctrl_cycles_per_up, U2_FLAG_TX_CTRL_UP_ENB | cycles_per_up);

    }

    //setting the packets per update (enabled by default)

    if (ups_per_fifo > 0.0){

        const size_t packets_per_up = size_t(usrp2_impl::sram_bytes/ups_per_fifo/data_transport->get_send_frame_size());

        _iface->poke32(_iface->regs.tx_ctrl_packets_per_up, U2_FLAG_TX_CTRL_UP_ENB | packets_per_up);

    //translate pps source enums

    switch(_clock_config.pps_source){

    case clock_config_t::PPS_SMA:  pps_flags |= U2_FLAG_TIME64_PPS_SMA;  break;

    default: throw std::runtime_error("unhandled clock configuration pps source");

    }

        switch(_clock_config.ref_source){

        case clock_config_t::REF_INT : _iface->poke32(_iface->regs.misc_ctrl_clock, 0x12); break;

        case clock_config_t::REF_SMA : _iface->poke32(_iface->regs.misc_ctrl_clock, 0x1C); break;

        default: throw std::runtime_error("unhandled clock configuration reference source");

        }

        _clock_ctrl->enable_external_ref(true); //USRP2P has an internal 10MHz TCXO

        switch(_clock_config.ref_source){

        case clock_config_t::REF_INT : _iface->poke32(_iface->regs.misc_ctrl_clock, 0x10); break;

        case clock_config_t::REF_SMA : _iface->poke32(_iface->regs.misc_ctrl_clock, 0x1C); break;

        default: throw std::runtime_error("unhandled clock configuration reference source");

        }

        _clock_ctrl->enable_external_ref(_clock_config.ref_source != clock_config_t::REF_INT);