Add example to synchronize USRPs to GPS time

1 files changed, 191 insertions, 0 deletions

diff --git a/host/examples/sync_to_gps.cpp b/host/examples/sync_to_gps.cpp
new file mode 100644
index 000000000..f27c3eff5
--- /dev/null
+++ b/host/examples/sync_to_gps.cpp
@@ -0,0 +1,191 @@
+//
+// Copyright 2016 Ettus Research
+//
+// 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/utils/thread_priority.hpp>
+#include <uhd/utils/safe_main.hpp>
+#include <uhd/usrp/multi_usrp.hpp>
+#include <boost/format.hpp>
+#include <boost/program_options.hpp>
+#include <boost/thread.hpp>
+#include <iostream>
+
+namespace po = boost::program_options;
+
+void print_notes(void)
+{
+    // Helpful notes
+    std::cout << boost::format("**************************************Helpful Notes on Clock/PPS Selection**************************************\n");
+    std::cout << boost::format("As you can see, the default 10 MHz Reference and 1 PPS signals are now from the GPSDO.\n");
+    std::cout << boost::format("If you would like to use the internal reference(TCXO) in other applications, you must configure that explicitly.\n");
+    std::cout << boost::format("You can no longer select the external SMAs for 10 MHz or 1 PPS signaling.\n");
+    std::cout << boost::format("****************************************************************************************************************\n");
+}
+
+int UHD_SAFE_MAIN(int argc, char *argv[])
+{
+    uhd::set_thread_priority_safe();
+
+    std::string args;
+
+    //Set up program options
+    po::options_description desc("Allowed options");
+    desc.add_options()
+    ("help", "help message")
+    ("args", po::value<std::string>(&args)->default_value(""), "USRP device arguments")
+    ;
+    po::variables_map vm;
+    po::store(po::parse_command_line(argc, argv, desc), vm);
+    po::notify(vm);
+
+    //Print the help message
+    if (vm.count("help"))
+    {
+        std::cout << boost::format("Synchronize USRP to GPS %s") % desc << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    //Create a USRP device
+    std::cout << boost::format("\nCreating the USRP device with: %s...\n") % args;
+    uhd::usrp::multi_usrp::sptr usrp = uhd::usrp::multi_usrp::make(args);
+    std::cout << boost::format("Using Device: %s\n") % usrp->get_pp_string();
+
+    try
+    {
+        size_t num_mboards = usrp->get_num_mboards();
+        size_t num_gps_locked = 0;
+        for (size_t mboard = 0; mboard < num_mboards; mboard++)
+        {
+            std::cout << "Synchronizing mboard " << mboard << ": " << usrp->get_mboard_name(mboard) << std::endl;
+
+            //Set references to GPSDO
+            usrp->set_clock_source("gpsdo", mboard);
+            usrp->set_time_source("gpsdo", mboard);
+
+            std::cout << std::endl;
+            print_notes();
+            std::cout << std::endl;
+
+            //Check for 10 MHz lock
+            std::vector<std::string> sensor_names = usrp->get_mboard_sensor_names(mboard);
+            if(std::find(sensor_names.begin(), sensor_names.end(), "ref_locked") != sensor_names.end())
+            {
+                std::cout << "Waiting for reference lock..." << std::flush;
+                bool ref_locked = false;
+                for (int i = 0; i < 30 and not ref_locked; i++)
+                {
+                    ref_locked = usrp->get_mboard_sensor("ref_locked", mboard).to_bool();
+                    if (not ref_locked)
+                    {
+                        std::cout << "." << std::flush;
+                        boost::this_thread::sleep(boost::posix_time::seconds(1));
+                    }
+                }
+                if(ref_locked)
+                {
+                    std::cout << "LOCKED" << std::endl;
+                } else {
+                    std::cout << "FAILED" << std::endl;
+                    throw uhd::runtime_error("Failed to lock to GPSDO 10 MHz Reference");
+                }
+            }
+            else
+            {
+                std::cout << boost::format("ref_locked sensor not present on this board.\n");
+            }
+
+            //Wait for GPS lock
+            bool gps_locked = usrp->get_mboard_sensor("gps_locked", mboard).to_bool();
+            if(gps_locked)
+            {
+                num_gps_locked++;
+                std::cout << boost::format("GPS Locked\n");
+            }
+            else
+            {
+                std::cerr << "WARNING:  GPS not locked - time will not be accurate until locked" << std::endl;
+            }
+
+            //Set to GPS time
+            uhd::time_spec_t gps_time = uhd::time_spec_t(time_t(usrp->get_mboard_sensor("gps_time", mboard).to_int()));
+            usrp->set_time_next_pps(gps_time+1.0, mboard);
+
+            //Wait for it to apply
+            //The wait is 2 seconds because N-Series has a known issue where
+            //the time at the last PPS does not properly update at the PPS edge
+            //when the time is actually set.
+            boost::this_thread::sleep(boost::posix_time::seconds(2));
+
+            //Check times
+            gps_time = uhd::time_spec_t(time_t(usrp->get_mboard_sensor("gps_time", mboard).to_int()));
+            uhd::time_spec_t time_last_pps = usrp->get_time_last_pps(mboard);
+            std::cout << "USRP time: " << (boost::format("%0.9f") % time_last_pps.get_real_secs()) << std::endl;
+            std::cout << "GPSDO time: " << (boost::format("%0.9f") % gps_time.get_real_secs()) << std::endl;
+            if (gps_time.get_real_secs() == time_last_pps.get_real_secs())
+                std::cout << std::endl << "SUCCESS: USRP time synchronized to GPS time" << std::endl << std::endl;
+            else
+                std::cerr << std::endl << "ERROR: Failed to synchronize USRP time to GPS time" << std::endl << std::endl;
+        }
+
+        if (num_gps_locked == num_mboards and num_mboards > 1)
+        {
+            //Check to see if all USRP times are aligned
+            //First, wait for PPS.
+            uhd::time_spec_t time_last_pps = usrp->get_time_last_pps();
+            while (time_last_pps == usrp->get_time_last_pps())
+            {
+                boost::this_thread::sleep(boost::posix_time::milliseconds(1));
+            }
+
+            //Sleep a little to make sure all devices have seen a PPS edge
+            boost::this_thread::sleep(boost::posix_time::milliseconds(200));
+
+            //Compare times across all mboards
+            bool all_matched = true;
+            uhd::time_spec_t mboard0_time = usrp->get_time_last_pps(0);
+            for (size_t mboard = 1; mboard < num_mboards; mboard++)
+            {
+                uhd::time_spec_t mboard_time = usrp->get_time_last_pps(mboard);
+                if (mboard_time != mboard0_time)
+                {
+                    all_matched = false;
+                    std::cerr << (boost::format("ERROR: Times are not aligned: USRP 0=%0.9f, USRP %d=%0.9f")
+                                  % mboard0_time.get_real_secs()
+                                  % mboard
+                                  % mboard_time.get_real_secs()) << std::endl;
+                }
+            }
+            if (all_matched)
+            {
+                std::cout << "SUCCESS: USRP times aligned" << std::endl << std::endl;
+            } else {
+                std::cout << "ERROR: USRP times are not aligned" << std::endl << std::endl;
+            }
+        }
+    }
+    catch (std::exception& e)
+    {
+        std::cout << boost::format("\nError: %s") % e.what();
+        std::cout << boost::format("This could mean that you have not installed the GPSDO correctly.\n\n");
+        std::cout << boost::format("Visit one of these pages if the problem persists:\n");
+        std::cout << boost::format(" * N2X0/E1X0: http://files.ettus.com/manual/page_gpsdo.html");
+        std::cout << boost::format(" * X3X0: http://files.ettus.com/manual/page_gpsdo_x3x0.html\n\n");
+        std::cout << boost::format(" * E3X0: http://files.ettus.com/manual/page_usrp_e3x0.html#e3x0_hw_gps\n\n");
+        exit(EXIT_FAILURE);
+    }
+
+    return EXIT_SUCCESS;
+}