Difference between revisions of "Getting Started with UHD and C++"

Revision as of 11:55, 1 May 2016

Application Note Number

AN-204

Revision History

Abstract

This AN explains how to write and build C++ programs that use the UHD API.

Overview

This Application Note will walk through building a basic C++ program with UHD. This program will initialize, configure the USRP device, set the sample rate, frequency, gain, bandwidth, and select the antenna.

Example code:

   #include <uhd/utils/thread_priority.hpp>
   #include <uhd/utils/safe_main.hpp>
   #include <uhd/usrp/multi_usrp.hpp>
   #include <uhd/exception.hpp>
   #include <uhd/types/tune_request.hpp>
   #include <boost/program_options.hpp>
   #include <boost/format.hpp>
   #include <boost/thread.hpp>
   #include <iostream>
   
   int UHD_SAFE_MAIN(int argc, char *argv[]) {
       uhd::set_thread_priority_safe();
   
       std::string device_args("addr=192.168.10.2");
       std::string subdev("A:0");
       std::string ant("TX/RX");
       std::string ref("internal");
   
       double rate(1e6);
       double freq(915e6);
       double gain(10);
       double bw(1e6);
   
       //create a usrp device
       std::cout << std::endl;
       std::cout << boost::format("Creating the usrp device with: %s...") % device_args << std::endl;
       uhd::usrp::multi_usrp::sptr usrp = uhd::usrp::multi_usrp::make(device_args);
   
       // Lock mboard clocks
       std::cout << boost::format("Lock mboard clocks: %f") % ref << std::endl;
       usrp->set_clock_source(ref);
       
       //always select the subdevice first, the channel mapping affects the other settings
       std::cout << boost::format("subdev set to: %f") % subdev << std::endl;
       usrp->set_rx_subdev_spec(subdev);
       std::cout << boost::format("Using Device: %s") % usrp->get_pp_string() << std::endl;
   
       //set the sample rate
       if (rate <= 0.0) {
           std::cerr << "Please specify a valid sample rate" << std::endl;
           return ~0;
       }
   
       // set sample rate
       std::cout << boost::format("Setting RX Rate: %f Msps...") % (rate / 1e6) << std::endl;
       usrp->set_rx_rate(rate);
       std::cout << boost::format("Actual RX Rate: %f Msps...") % (usrp->get_rx_rate() / 1e6) << std::endl << std::endl;
   
       // set freq
       std::cout << boost::format("Setting RX Freq: %f MHz...") % (freq / 1e6) << std::endl;
       uhd::tune_request_t tune_request(freq);
       usrp->set_rx_freq(tune_request);
       std::cout << boost::format("Actual RX Freq: %f MHz...") % (usrp->get_rx_freq() / 1e6) << std::endl << std::endl;
   
       // set the rf gain
       std::cout << boost::format("Setting RX Gain: %f dB...") % gain << std::endl;
       usrp->set_rx_gain(gain);
       std::cout << boost::format("Actual RX Gain: %f dB...") % usrp->get_rx_gain() << std::endl << std::endl;
   
       // set the IF filter bandwidth
       std::cout << boost::format("Setting RX Bandwidth: %f MHz...") % (bw / 1e6) << std::endl;
       usrp->set_rx_bandwidth(bw);
       std::cout << boost::format("Actual RX Bandwidth: %f MHz...") % (usrp->get_rx_bandwidth() / 1e6) << std::endl << std::endl;
   
       // set the antenna
       std::cout << boost::format("Setting RX Antenna: %s") % ant << std::endl;
       usrp->set_rx_antenna(ant);
       std::cout << boost::format("Actual RX Antenna: %s") % usrp->get_rx_antenna() << std::endl << std::endl;
   
       return EXIT_SUCCESS;
   }

Use the uhd/host/examples/init_usrp/CMakeLists.txt file as template - Add the names of your C++ source files to the add_executable(...) section - Put both modified CMakeLists.txt file and C++ file into an empty folder - Create a “build” folder and invoke CMake the usual way:

   mkdir build
   cd build
   cmake ../
   make -j4