src/main/telemetry/mavlink.c

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 /*
  22  * telemetry_mavlink.c
  23  *
  24  * Author: Konstantin Sharlaimov
  25  */
  26 #include <stdbool.h>
  27 #include <stdint.h>
  28 #include <string.h>
  29
  30 #include "platform.h"
  31
  32 #if defined(USE_TELEMETRY_MAVLINK)
  33
  34 #include "common/maths.h"
  35 #include "common/axis.h"
  36 #include "common/color.h"
  37
  38 #include "config/feature.h"
  39 #include "pg/pg.h"
  40 #include "pg/pg_ids.h"
  41 #include "pg/rx.h"
  42
  43 #include "drivers/accgyro/accgyro.h"
  44 #include "drivers/sensor.h"
  45 #include "drivers/time.h"
  46
  47 #include "config/config.h"
  48 #include "fc/rc_controls.h"
  49 #include "fc/runtime_config.h"
  50
  51 #include "flight/mixer.h"
  52 #include "flight/pid.h"
  53 #include "flight/imu.h"
  54 #include "flight/failsafe.h"
  55 #include "flight/position.h"
  56
  57 #include "io/serial.h"
  58 #include "io/gimbal.h"
  59 #include "io/gps.h"
  60 #include "io/ledstrip.h"
  61
  62 #include "rx/rx.h"
  63
  64 #include "sensors/sensors.h"
  65 #include "sensors/acceleration.h"
  66 #include "sensors/gyro.h"
  67 #include "sensors/barometer.h"
  68 #include "sensors/boardalignment.h"
  69 #include "sensors/battery.h"
  70
  71 #include "telemetry/telemetry.h"
  72 #include "telemetry/mavlink.h"
  73
  74 // mavlink library uses unnames unions that's causes GCC to complain if -Wpedantic is used
  75 // until this is resolved in mavlink library - ignore -Wpedantic for mavlink code
  76 #pragma GCC diagnostic push
  77 #pragma GCC diagnostic ignored "-Wpedantic"
  78 #include "common/mavlink.h"
  79 #pragma GCC diagnostic pop
  80
  81 #define TELEMETRY_MAVLINK_INITIAL_PORT_MODE MODE_TX
  82 #define TELEMETRY_MAVLINK_MAXRATE 50
  83 #define TELEMETRY_MAVLINK_DELAY ((1000 * 1000) / TELEMETRY_MAVLINK_MAXRATE)
  84
  85 extern uint16_t rssi; // FIXME dependency on mw.c
  86
  87 static serialPort_t *mavlinkPort = NULL;
  88 static const serialPortConfig_t *portConfig;
  89
  90 static bool mavlinkTelemetryEnabled =  false;
  91 static portSharing_e mavlinkPortSharing;
  92
  93 /* MAVLink datastream rates in Hz */
  94 static const uint8_t mavRates[] = {
  95     [MAV_DATA_STREAM_EXTENDED_STATUS] = 2, //2Hz
  96     [MAV_DATA_STREAM_RC_CHANNELS] = 5, //5Hz
  97     [MAV_DATA_STREAM_POSITION] = 2, //2Hz
  98     [MAV_DATA_STREAM_EXTRA1] = 10, //10Hz
  99     [MAV_DATA_STREAM_EXTRA2] = 10 //2Hz
 100 };
 101
 102 #define MAXSTREAMS (sizeof(mavRates) / sizeof(mavRates[0]))
 103
 104 static uint8_t mavTicks[MAXSTREAMS];
 105 static mavlink_message_t mavMsg;
 106 static uint8_t mavBuffer[MAVLINK_MAX_PACKET_LEN];
 107 static uint32_t lastMavlinkMessage = 0;
 108
 109 static int mavlinkStreamTrigger(enum MAV_DATA_STREAM streamNum)
 110 {
 111     uint8_t rate = (uint8_t) mavRates[streamNum];
 112     if (rate == 0) {
 113         return 0;
 114     }
 115
 116     if (mavTicks[streamNum] == 0) {
 117         // we're triggering now, setup the next trigger point
 118         if (rate > TELEMETRY_MAVLINK_MAXRATE) {
 119             rate = TELEMETRY_MAVLINK_MAXRATE;
 120         }
 121
 122         mavTicks[streamNum] = (TELEMETRY_MAVLINK_MAXRATE / rate);
 123         return 1;
 124     }
 125
 126     // count down at TASK_RATE_HZ
 127     mavTicks[streamNum]--;
 128     return 0;
 129 }
 130
 131
 132 static void mavlinkSerialWrite(uint8_t * buf, uint16_t length)
 133 {
 134     for (int i = 0; i < length; i++)
 135         serialWrite(mavlinkPort, buf[i]);
 136 }
 137
 138 static int16_t headingOrScaledMilliAmpereHoursDrawn(void)
 139 {
 140     if (isAmperageConfigured() && telemetryConfig()->mavlink_mah_as_heading_divisor > 0) {
 141         // In the Connex Prosight OSD, this goes between 0 and 999, so it will need to be scaled in that range.
 142         return getMAhDrawn() / telemetryConfig()->mavlink_mah_as_heading_divisor;
 143     }
 144     // heading Current heading in degrees, in compass units (0..360, 0=north)
 145     return DECIDEGREES_TO_DEGREES(attitude.values.yaw);
 146 }
 147
 148
 149 void freeMAVLinkTelemetryPort(void)
 150 {
 151     closeSerialPort(mavlinkPort);
 152     mavlinkPort = NULL;
 153     mavlinkTelemetryEnabled = false;
 154 }
 155
 156 void initMAVLinkTelemetry(void)
 157 {
 158     portConfig = findSerialPortConfig(FUNCTION_TELEMETRY_MAVLINK);
 159     mavlinkPortSharing = determinePortSharing(portConfig, FUNCTION_TELEMETRY_MAVLINK);
 160 }
 161
 162 void configureMAVLinkTelemetryPort(void)
 163 {
 164     if (!portConfig) {
 165         return;
 166     }
 167
 168     baudRate_e baudRateIndex = portConfig->telemetry_baudrateIndex;
 169     if (baudRateIndex == BAUD_AUTO) {
 170         // default rate for minimOSD
 171         baudRateIndex = BAUD_57600;
 172     }
 173
 174     mavlinkPort = openSerialPort(portConfig->identifier, FUNCTION_TELEMETRY_MAVLINK, NULL, NULL, baudRates[baudRateIndex], TELEMETRY_MAVLINK_INITIAL_PORT_MODE, telemetryConfig()->telemetry_inverted ? SERIAL_INVERTED : SERIAL_NOT_INVERTED);
 175
 176     if (!mavlinkPort) {
 177         return;
 178     }
 179
 180     mavlinkTelemetryEnabled = true;
 181 }
 182
 183 void checkMAVLinkTelemetryState(void)
 184 {
 185     if (portConfig && telemetryCheckRxPortShared(portConfig, rxRuntimeState.serialrxProvider)) {
 186         if (!mavlinkTelemetryEnabled && telemetrySharedPort != NULL) {
 187             mavlinkPort = telemetrySharedPort;
 188             mavlinkTelemetryEnabled = true;
 189         }
 190     } else {
 191         bool newTelemetryEnabledValue = telemetryDetermineEnabledState(mavlinkPortSharing);
 192
 193         if (newTelemetryEnabledValue == mavlinkTelemetryEnabled) {
 194             return;
 195         }
 196
 197         if (newTelemetryEnabledValue)
 198             configureMAVLinkTelemetryPort();
 199         else
 200             freeMAVLinkTelemetryPort();
 201     }
 202 }
 203
 204 void mavlinkSendSystemStatus(void)
 205 {
 206     uint16_t msgLength;
 207
 208     uint32_t onboardControlAndSensors = 35843;
 209
 210     /*
 211     onboard_control_sensors_present Bitmask
 212     fedcba9876543210
 213     1000110000000011    For all   = 35843
 214     0001000000000100    With Mag  = 4100
 215     0010000000001000    With Baro = 8200
 216     0100000000100000    With GPS  = 16416
 217     0000001111111111
 218     */
 219
 220     if (sensors(SENSOR_MAG))  onboardControlAndSensors |=  4100;
 221     if (sensors(SENSOR_BARO)) onboardControlAndSensors |=  8200;
 222     if (sensors(SENSOR_GPS))  onboardControlAndSensors |= 16416;
 223
 224     uint16_t batteryVoltage = 0;
 225     int16_t batteryAmperage = -1;
 226     int8_t batteryRemaining = 100;
 227
 228     if (getBatteryState() < BATTERY_NOT_PRESENT) {
 229         batteryVoltage = isBatteryVoltageConfigured() ? getBatteryVoltage() * 10 : batteryVoltage;
 230         batteryAmperage = isAmperageConfigured() ? getAmperage() : batteryAmperage;
 231         batteryRemaining = isBatteryVoltageConfigured() ? calculateBatteryPercentageRemaining() : batteryRemaining;
 232     }
 233
 234     mavlink_msg_sys_status_pack(0, 200, &mavMsg,
 235         // onboard_control_sensors_present Bitmask showing which onboard controllers and sensors are present.
 236         //Value of 0: not present. Value of 1: present. Indices: 0: 3D gyro, 1: 3D acc, 2: 3D mag, 3: absolute pressure,
 237         // 4: differential pressure, 5: GPS, 6: optical flow, 7: computer vision position, 8: laser based position,
 238         // 9: external ground-truth (Vicon or Leica). Controllers: 10: 3D angular rate control 11: attitude stabilization,
 239         // 12: yaw position, 13: z/altitude control, 14: x/y position control, 15: motor outputs / control
 240         onboardControlAndSensors,
 241         // onboard_control_sensors_enabled Bitmask showing which onboard controllers and sensors are enabled
 242         onboardControlAndSensors,
 243         // onboard_control_sensors_health Bitmask showing which onboard controllers and sensors are operational or have an error.
 244         onboardControlAndSensors & 1023,
 245         // load Maximum usage in percent of the mainloop time, (0%: 0, 100%: 1000) should be always below 1000
 246         0,
 247         // voltage_battery Battery voltage, in millivolts (1 = 1 millivolt)
 248         batteryVoltage,
 249         // current_battery Battery current, in 10*milliamperes (1 = 10 milliampere), -1: autopilot does not measure the current
 250         batteryAmperage,
 251         // battery_remaining Remaining battery energy: (0%: 0, 100%: 100), -1: autopilot estimate the remaining battery
 252         batteryRemaining,
 253         // drop_rate_comm Communication drops in percent, (0%: 0, 100%: 10'000), (UART, I2C, SPI, CAN), dropped packets on all links (packets that were corrupted on reception on the MAV)
 254         0,
 255         // errors_comm Communication errors (UART, I2C, SPI, CAN), dropped packets on all links (packets that were corrupted on reception on the MAV)
 256         0,
 257         // errors_count1 Autopilot-specific errors
 258         0,
 259         // errors_count2 Autopilot-specific errors
 260         0,
 261         // errors_count3 Autopilot-specific errors
 262         0,
 263         // errors_count4 Autopilot-specific errors
 264         0);
 265     msgLength = mavlink_msg_to_send_buffer(mavBuffer, &mavMsg);
 266     mavlinkSerialWrite(mavBuffer, msgLength);
 267 }
 268
 269 void mavlinkSendRCChannelsAndRSSI(void)
 270 {
 271     uint16_t msgLength;
 272     mavlink_msg_rc_channels_raw_pack(0, 200, &mavMsg,
 273         // time_boot_ms Timestamp (milliseconds since system boot)
 274         millis(),
 275         // port Servo output port (set of 8 outputs = 1 port). Most MAVs will just use one, but this allows to encode more than 8 servos.
 276         0,
 277         // chan1_raw RC channel 1 value, in microseconds
 278         (rxRuntimeState.channelCount >= 1) ? rcData[0] : 0,
 279         // chan2_raw RC channel 2 value, in microseconds
 280         (rxRuntimeState.channelCount >= 2) ? rcData[1] : 0,
 281         // chan3_raw RC channel 3 value, in microseconds
 282         (rxRuntimeState.channelCount >= 3) ? rcData[2] : 0,
 283         // chan4_raw RC channel 4 value, in microseconds
 284         (rxRuntimeState.channelCount >= 4) ? rcData[3] : 0,
 285         // chan5_raw RC channel 5 value, in microseconds
 286         (rxRuntimeState.channelCount >= 5) ? rcData[4] : 0,
 287         // chan6_raw RC channel 6 value, in microseconds
 288         (rxRuntimeState.channelCount >= 6) ? rcData[5] : 0,
 289         // chan7_raw RC channel 7 value, in microseconds
 290         (rxRuntimeState.channelCount >= 7) ? rcData[6] : 0,
 291         // chan8_raw RC channel 8 value, in microseconds
 292         (rxRuntimeState.channelCount >= 8) ? rcData[7] : 0,
 293         // rssi Receive signal strength indicator, 0: 0%, 255: 100%
 294         constrain(scaleRange(getRssi(), 0, RSSI_MAX_VALUE, 0, 255), 0, 255));
 295     msgLength = mavlink_msg_to_send_buffer(mavBuffer, &mavMsg);
 296     mavlinkSerialWrite(mavBuffer, msgLength);
 297 }
 298
 299 #if defined(USE_GPS)
 300 void mavlinkSendPosition(void)
 301 {
 302     uint16_t msgLength;
 303     uint8_t gpsFixType = 0;
 304
 305     if (!sensors(SENSOR_GPS))
 306         return;
 307
 308     if (!STATE(GPS_FIX)) {
 309         gpsFixType = 1;
 310     }
 311     else {
 312         if (gpsSol.numSat < 5) {
 313             gpsFixType = 2;
 314         }
 315         else {
 316             gpsFixType = 3;
 317         }
 318     }
 319
 320     mavlink_msg_gps_raw_int_pack(0, 200, &mavMsg,
 321         // time_usec Timestamp (microseconds since UNIX epoch or microseconds since system boot)
 322         micros(),
 323         // fix_type 0-1: no fix, 2: 2D fix, 3: 3D fix. Some applications will not use the value of this field unless it is at least two, so always correctly fill in the fix.
 324         gpsFixType,
 325         // lat Latitude in 1E7 degrees
 326         gpsSol.llh.lat,
 327         // lon Longitude in 1E7 degrees
 328         gpsSol.llh.lon,
 329         // alt Altitude in 1E3 meters (millimeters) above MSL
 330         gpsSol.llh.altCm * 10,
 331         // eph GPS HDOP horizontal dilution of position in cm (m*100). If unknown, set to: 65535
 332         65535,
 333         // epv GPS VDOP horizontal dilution of position in cm (m*100). If unknown, set to: 65535
 334         65535,
 335         // vel GPS ground speed (m/s * 100). If unknown, set to: 65535
 336         gpsSol.groundSpeed,
 337         // cog Course over ground (NOT heading, but direction of movement) in degrees * 100, 0.0..359.99 degrees. If unknown, set to: 65535
 338         gpsSol.groundCourse * 10,
 339         // satellites_visible Number of satellites visible. If unknown, set to 255
 340         gpsSol.numSat);
 341     msgLength = mavlink_msg_to_send_buffer(mavBuffer, &mavMsg);
 342     mavlinkSerialWrite(mavBuffer, msgLength);
 343
 344     // Global position
 345     mavlink_msg_global_position_int_pack(0, 200, &mavMsg,
 346         // time_usec Timestamp (microseconds since UNIX epoch or microseconds since system boot)
 347         micros(),
 348         // lat Latitude in 1E7 degrees
 349         gpsSol.llh.lat,
 350         // lon Longitude in 1E7 degrees
 351         gpsSol.llh.lon,
 352         // alt Altitude in 1E3 meters (millimeters) above MSL
 353         gpsSol.llh.altCm * 10,
 354         // relative_alt Altitude above ground in meters, expressed as * 1000 (millimeters)
 355         getEstimatedAltitudeCm() * 10,
 356         // Ground X Speed (Latitude), expressed as m/s * 100
 357         0,
 358         // Ground Y Speed (Longitude), expressed as m/s * 100
 359         0,
 360         // Ground Z Speed (Altitude), expressed as m/s * 100
 361         0,
 362         // heading Current heading in degrees, in compass units (0..360, 0=north)
 363         headingOrScaledMilliAmpereHoursDrawn()
 364     );
 365     msgLength = mavlink_msg_to_send_buffer(mavBuffer, &mavMsg);
 366     mavlinkSerialWrite(mavBuffer, msgLength);
 367
 368     mavlink_msg_gps_global_origin_pack(0, 200, &mavMsg,
 369         // latitude Latitude (WGS84), expressed as * 1E7
 370         GPS_home[GPS_LATITUDE],
 371         // longitude Longitude (WGS84), expressed as * 1E7
 372         GPS_home[GPS_LONGITUDE],
 373         // altitude Altitude(WGS84), expressed as * 1000
 374         0);
 375     msgLength = mavlink_msg_to_send_buffer(mavBuffer, &mavMsg);
 376     mavlinkSerialWrite(mavBuffer, msgLength);
 377 }
 378 #endif
 379
 380 void mavlinkSendAttitude(void)
 381 {
 382     uint16_t msgLength;
 383     mavlink_msg_attitude_pack(0, 200, &mavMsg,
 384         // time_boot_ms Timestamp (milliseconds since system boot)
 385         millis(),
 386         // roll Roll angle (rad)
 387         DECIDEGREES_TO_RADIANS(attitude.values.roll),
 388         // pitch Pitch angle (rad)
 389         DECIDEGREES_TO_RADIANS(-attitude.values.pitch),
 390         // yaw Yaw angle (rad)
 391         DECIDEGREES_TO_RADIANS(attitude.values.yaw),
 392         // rollspeed Roll angular speed (rad/s)
 393         0,
 394         // pitchspeed Pitch angular speed (rad/s)
 395         0,
 396         // yawspeed Yaw angular speed (rad/s)
 397         0);
 398     msgLength = mavlink_msg_to_send_buffer(mavBuffer, &mavMsg);
 399     mavlinkSerialWrite(mavBuffer, msgLength);
 400 }
 401
 402 void mavlinkSendHUDAndHeartbeat(void)
 403 {
 404     uint16_t msgLength;
 405     float mavAltitude = 0;
 406     float mavGroundSpeed = 0;
 407     float mavAirSpeed = 0;
 408     float mavClimbRate = 0;
 409
 410 #if defined(USE_GPS)
 411     // use ground speed if source available
 412     if (sensors(SENSOR_GPS)) {
 413         mavGroundSpeed = gpsSol.groundSpeed / 100.0f;
 414     }
 415 #endif
 416
 417     mavAltitude = getEstimatedAltitudeCm() / 100.0;
 418
 419     mavlink_msg_vfr_hud_pack(0, 200, &mavMsg,
 420         // airspeed Current airspeed in m/s
 421         mavAirSpeed,
 422         // groundspeed Current ground speed in m/s
 423         mavGroundSpeed,
 424         // heading Current heading in degrees, in compass units (0..360, 0=north)
 425         headingOrScaledMilliAmpereHoursDrawn(),
 426         // throttle Current throttle setting in integer percent, 0 to 100
 427         scaleRange(constrain(rcData[THROTTLE], PWM_RANGE_MIN, PWM_RANGE_MAX), PWM_RANGE_MIN, PWM_RANGE_MAX, 0, 100),
 428         // alt Current altitude (MSL), in meters, if we have sonar or baro use them, otherwise use GPS (less accurate)
 429         mavAltitude,
 430         // climb Current climb rate in meters/second
 431         mavClimbRate);
 432     msgLength = mavlink_msg_to_send_buffer(mavBuffer, &mavMsg);
 433     mavlinkSerialWrite(mavBuffer, msgLength);
 434
 435
 436     uint8_t mavModes = MAV_MODE_FLAG_MANUAL_INPUT_ENABLED;
 437     if (ARMING_FLAG(ARMED))
 438         mavModes |= MAV_MODE_FLAG_SAFETY_ARMED;
 439
 440     uint8_t mavSystemType;
 441     switch (mixerConfig()->mixerMode)
 442     {
 443         case MIXER_TRI:
 444             mavSystemType = MAV_TYPE_TRICOPTER;
 445             break;
 446         case MIXER_QUADP:
 447         case MIXER_QUADX:
 448         case MIXER_Y4:
 449         case MIXER_VTAIL4:
 450             mavSystemType = MAV_TYPE_QUADROTOR;
 451             break;
 452         case MIXER_Y6:
 453         case MIXER_HEX6:
 454         case MIXER_HEX6X:
 455             mavSystemType = MAV_TYPE_HEXAROTOR;
 456             break;
 457         case MIXER_OCTOX8:
 458         case MIXER_OCTOFLATP:
 459         case MIXER_OCTOFLATX:
 460             mavSystemType = MAV_TYPE_OCTOROTOR;
 461             break;
 462         case MIXER_FLYING_WING:
 463         case MIXER_AIRPLANE:
 464         case MIXER_CUSTOM_AIRPLANE:
 465             mavSystemType = MAV_TYPE_FIXED_WING;
 466             break;
 467         case MIXER_HELI_120_CCPM:
 468         case MIXER_HELI_90_DEG:
 469             mavSystemType = MAV_TYPE_HELICOPTER;
 470             break;
 471         default:
 472             mavSystemType = MAV_TYPE_GENERIC;
 473             break;
 474     }
 475
 476     // Custom mode for compatibility with APM OSDs
 477     uint8_t mavCustomMode = 1;  // Acro by default
 478
 479     if (FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE)) {
 480         mavCustomMode = 0;      //Stabilize
 481         mavModes |= MAV_MODE_FLAG_STABILIZE_ENABLED;
 482     }
 483
 484     uint8_t mavSystemState = 0;
 485     if (ARMING_FLAG(ARMED)) {
 486         if (failsafeIsActive()) {
 487             mavSystemState = MAV_STATE_CRITICAL;
 488         }
 489         else {
 490             mavSystemState = MAV_STATE_ACTIVE;
 491         }
 492     }
 493     else {
 494         mavSystemState = MAV_STATE_STANDBY;
 495     }
 496
 497     mavlink_msg_heartbeat_pack(0, 200, &mavMsg,
 498         // type Type of the MAV (quadrotor, helicopter, etc., up to 15 types, defined in MAV_TYPE ENUM)
 499         mavSystemType,
 500         // autopilot Autopilot type / class. defined in MAV_AUTOPILOT ENUM
 501         MAV_AUTOPILOT_GENERIC,
 502         // base_mode System mode bitfield, see MAV_MODE_FLAGS ENUM in mavlink/include/mavlink_types.h
 503         mavModes,
 504         // custom_mode A bitfield for use for autopilot-specific flags.
 505         mavCustomMode,
 506         // system_status System status flag, see MAV_STATE ENUM
 507         mavSystemState);
 508     msgLength = mavlink_msg_to_send_buffer(mavBuffer, &mavMsg);
 509     mavlinkSerialWrite(mavBuffer, msgLength);
 510 }
 511
 512 void processMAVLinkTelemetry(void)
 513 {
 514     // is executed @ TELEMETRY_MAVLINK_MAXRATE rate
 515     if (mavlinkStreamTrigger(MAV_DATA_STREAM_EXTENDED_STATUS)) {
 516         mavlinkSendSystemStatus();
 517     }
 518
 519     if (mavlinkStreamTrigger(MAV_DATA_STREAM_RC_CHANNELS)) {
 520         mavlinkSendRCChannelsAndRSSI();
 521     }
 522
 523 #ifdef USE_GPS
 524     if (mavlinkStreamTrigger(MAV_DATA_STREAM_POSITION)) {
 525         mavlinkSendPosition();
 526     }
 527 #endif
 528
 529     if (mavlinkStreamTrigger(MAV_DATA_STREAM_EXTRA1)) {
 530         mavlinkSendAttitude();
 531     }
 532
 533     if (mavlinkStreamTrigger(MAV_DATA_STREAM_EXTRA2)) {
 534         mavlinkSendHUDAndHeartbeat();
 535     }
 536 }
 537
 538 void handleMAVLinkTelemetry(void)
 539 {
 540     if (!mavlinkTelemetryEnabled) {
 541         return;
 542     }
 543
 544     if (!mavlinkPort) {
 545         return;
 546     }
 547
 548     uint32_t now = micros();
 549     if ((now - lastMavlinkMessage) >= TELEMETRY_MAVLINK_DELAY) {
 550         processMAVLinkTelemetry();
 551         lastMavlinkMessage = now;
 552     }
 553 }
 554
 555 #endif