Function to set USRP time to GPS time

gistfile1.txt

static uhd_error set_time_to_gps_time(rf_uhd_handler_t* handler)
{
  const char     sensor_name[] = "gps_time";

  uhd_string_vector_handle sensors;
  uhd_string_vector_make(&sensors);

  uhd_error error = uhd_usrp_get_mboard_sensor_names(handler->usrp, 0, &sensors);

#if PRINT_SENSOR_NAMES
  size_t sensors_len;
  uhd_string_vector_size(sensors, &sensors_len);
  for (int i = 0; i < sensors_len; i++) {
    char buff[256];
    uhd_string_vector_at(sensors, i, buff, 128);
    printf("sensor %s present\n", buff);
  }
#endif

  if (error == UHD_ERROR_NONE && find_string(sensors, sensor_name)) {
    uhd_sensor_value_handle value_h;
    uhd_sensor_value_make_from_string(&value_h, "w", "t", "f");
    error = uhd_usrp_get_mboard_sensor(handler->usrp, sensor_name, 0, &value_h);

    int full_secs = 0;
    if (error == UHD_ERROR_NONE) {
      uhd_sensor_value_data_type_t sensor_dtype;
      uhd_sensor_value_data_type(value_h, &sensor_dtype);
      full_secs = uhd_sensor_value_to_int(value_h, &full_secs);

      printf("gps full_secs=%d\n", full_secs);

      double frac_secs;
      uhd_sensor_value_data_type(value_h, &sensor_dtype);
      full_secs = uhd_sensor_value_to_realnum(value_h, &frac_secs);

      printf("gps frac_secs=%f\n", frac_secs);

      full_secs = frac_secs;
      printf("gps after rounding full_secs=%d\n", full_secs);

      // seems to work
      error = uhd_usrp_set_time_unknown_pps(handler->usrp, full_secs + 1, 0.0);
      // doesn't work
      // error = uhd_usrp_set_time_next_pps(handler->usrp, full_secs+1, 0.0, 0);
      if (error != UHD_ERROR_NONE) {
        char err_msg[256];
        uhd_usrp_last_error(handler->usrp, err_msg, 256);
        fprintf(stderr, "Error code %d: %s\n", error, err_msg);
      }

      // sleep a second to make sure values are set correctly
      sleep(1);
    }
    uhd_sensor_value_free(&value_h);
  }
  if (error != UHD_ERROR_NONE) {
    fprintf(stderr, "USRP has no sensor \"%s\", or reading failed. UHD error: %i\n", sensor_name, error);
  }

  uhd_string_vector_free(&sensors);

  return error;
}