AP_Frsky_SPort_Passthrough.cpp

#include "AP_Frsky_SPort_Passthrough.h"

#if AP_FRSKY_SPORT_PASSTHROUGH_ENABLED

#include <AP_AHRS/AP_AHRS.h>
#include <AP_BattMonitor/AP_BattMonitor.h>
#include <AP_GPS/AP_GPS.h>
#include <AP_HAL/utility/RingBuffer.h>
#include <AP_InertialSensor/AP_InertialSensor.h>
#include <AP_Notify/AP_Notify.h>
#include <AP_RangeFinder/AP_RangeFinder.h>
#include <AP_RPM/AP_RPM.h>
#include <AP_Terrain/AP_Terrain.h>
#include <AC_Fence/AC_Fence.h>
#include <AP_Vehicle/AP_Vehicle.h>
#include <GCS_MAVLink/GCS.h>
#if APM_BUILD_TYPE(APM_BUILD_Rover)
#include <AP_WindVane/AP_WindVane.h>
#endif

#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
#include "AP_Frsky_MAVlite.h"
#endif //HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
#include "AP_Frsky_Parameters.h"

/*
for FrSky SPort Passthrough
*/
// data bits preparation
// for parameter data
#define PARAM_ID_OFFSET             24
#define PARAM_VALUE_LIMIT           0xFFFFFF
// for gps status data
#define GPS_SATS_LIMIT              0xF
#define GPS_STATUS_LIMIT            0x3
#define GPS_STATUS_OFFSET           4
#define GPS_HDOP_OFFSET             6
#define GPS_ADVSTATUS_OFFSET        14
#define GPS_ALTMSL_OFFSET           22
// for battery data
#define BATT_VOLTAGE_LIMIT          0x1FF
#define BATT_CURRENT_OFFSET         9
#define BATT_TOTALMAH_LIMIT         0x7FFF
#define BATT_TOTALMAH_OFFSET        17
// for autopilot status data
#define AP_CONTROL_MODE_LIMIT       0x1F
#define AP_SIMPLE_OFFSET            5
#define AP_SSIMPLE_OFFSET           6
#define AP_FLYING_OFFSET            7
#define AP_ARMED_OFFSET             8
#define AP_BATT_FS_OFFSET           9
#define AP_EKF_FS_OFFSET            10
#define AP_FS_OFFSET                12
#define AP_FENCE_PRESENT_OFFSET     13
#define AP_FENCE_BREACH_OFFSET      14
#define AP_THROTTLE_OFFSET          19
#define AP_IMU_TEMP_MIN             19.0f
#define AP_IMU_TEMP_MAX             82.0f
#define AP_IMU_TEMP_OFFSET          26
// for home position related data
#define HOME_ALT_OFFSET             12
#define HOME_BEARING_LIMIT          0x7F
#define HOME_BEARING_OFFSET         25
// for velocity and yaw data
#define VELANDYAW_XYVEL_OFFSET      9
#define VELANDYAW_YAW_LIMIT         0x7FF
#define VELANDYAW_YAW_OFFSET        17
#define VELANDYAW_ARSPD_OFFSET      28
// for attitude (roll, pitch) and range data
#define ATTIANDRNG_ROLL_LIMIT       0x7FF
#define ATTIANDRNG_PITCH_LIMIT      0x3FF
#define ATTIANDRNG_PITCH_OFFSET     11
#define ATTIANDRNG_RNGFND_OFFSET    21
// for terrain data
#define TERRAIN_UNHEALTHY_OFFSET    13
// for wind data
#define WIND_ANGLE_LIMIT            0x7F
#define WIND_SPEED_OFFSET           7
#define WIND_APPARENT_ANGLE_OFFSET  15
#define WIND_APPARENT_SPEED_OFFSET  22
// for waypoint data
#define WP_NUMBER_LIMIT             2047
#define WP_DISTANCE_LIMIT           1023000
#define WP_DISTANCE_OFFSET          11
#define WP_BEARING_OFFSET           23

extern const AP_HAL::HAL& hal;

AP_Frsky_SPort_Passthrough *AP_Frsky_SPort_Passthrough::singleton;

bool AP_Frsky_SPort_Passthrough::init()
{
    if (!AP_RCTelemetry::init()) {
        return false;
    }
    return AP_Frsky_SPort::init();
}

bool AP_Frsky_SPort_Passthrough::init_serial_port()
{
    if (_use_external_data) {
        return true;
    }
    return AP_Frsky_SPort::init_serial_port();
}

void  AP_Frsky_SPort_Passthrough::send_sport_frame(uint8_t frame, uint16_t appid, uint32_t data)
{
    if (_use_external_data) {
        external_data.packet.frame = frame;
        external_data.packet.appid = appid;
        external_data.packet.data = data;
        external_data.pending = true;
        return;
    }

    return AP_Frsky_SPort::send_sport_frame(frame, appid, data);
}

/*
  setup ready for passthrough telem
 */
void AP_Frsky_SPort_Passthrough::setup_wfq_scheduler(void)
{
    // initialize packet weights for the WFQ scheduler
    // priority[i] = 1/_scheduler.packet_weight[i]
    // rate[i] = LinkRate * ( priority[i] / (sum(priority[1-n])) )
    set_scheduler_entry(TEXT, 35, 28);          // 0x5000 status text (dynamic)
    set_scheduler_entry(ATTITUDE, 50, 38);      // 0x5006 Attitude and range (dynamic)
    set_scheduler_entry(GPS_LAT, 550, 280);     // 0x800 GPS lat
    set_scheduler_entry(GPS_LON, 550, 280);     // 0x800 GPS lon
    set_scheduler_entry(VEL_YAW, 400, 250);     // 0x5005 Vel and Yaw
    set_scheduler_entry(AP_STATUS, 700, 500);   // 0x5001 AP status
    set_scheduler_entry(GPS_STATUS, 700, 500);  // 0x5002 GPS status
    set_scheduler_entry(HOME, 400, 500);        // 0x5004 Home
    set_scheduler_entry(BATT_2, 1300, 500);     // 0x5008 Battery 2 status
    set_scheduler_entry(BATT_1, 1300, 500);     // 0x5003 Battery 1 status
    set_scheduler_entry(PARAM, 1700, 1000);     // 0x5007 parameters
    set_scheduler_entry(RPM, 300, 330);         // 0x500A rpm sensors 1 and 2
    set_scheduler_entry(TERRAIN, 700, 500);     // 0x500B terrain data
    set_scheduler_entry(WIND, 700, 500);        // 0x500C wind data
    set_scheduler_entry(WAYPOINT, 750, 500);    // 0x500D waypoint data
    set_scheduler_entry(UDATA, 5000, 200);      // user data

    // initialize default sport sensor ID
    set_sensor_id(_frsky_parameters->_dnlink_id, downlink_sensor_id);
#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    set_scheduler_entry(MAV, 35, 25);           // mavlite
    // initialize sport sensor IDs
    set_sensor_id(_frsky_parameters->_uplink_id, _SPort_bidir.uplink_sensor_id);
    set_sensor_id(_frsky_parameters->_dnlink1_id, _SPort_bidir.downlink1_sensor_id);
    set_sensor_id(_frsky_parameters->_dnlink2_id, _SPort_bidir.downlink2_sensor_id);
    // initialize sport
    hal.scheduler->register_io_process(FUNCTOR_BIND_MEMBER(&AP_Frsky_SPort_Passthrough::process_rx_queue, void));
#endif //HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
}

/*
  dynamically change scheduler priorities based on queue sizes
*/
void AP_Frsky_SPort_Passthrough::adjust_packet_weight(bool queue_empty)
{
    /*
        When queues are empty set a low priority (high weight), when queues
        are not empty set a higher priority (low weight) based on the following
        relative priority order: mavlite > status text > attitude.
     */
#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    if (!_SPort_bidir.tx_packet_queue.is_empty()) {
        _scheduler.packet_weight[MAV] = 30;             // mavlite
        if (!queue_empty) {
            _scheduler.packet_weight[TEXT] = 45;        // messages
            _scheduler.packet_weight[ATTITUDE] = 80;    // attitude
        } else {
            _scheduler.packet_weight[TEXT] = 5000;      // messages
            _scheduler.packet_weight[ATTITUDE] = 80;    // attitude
        }
    } else {
        _scheduler.packet_weight[MAV] = 5000;           // mavlite
        if (!queue_empty) {
            _scheduler.packet_weight[TEXT] = 45;        // messages
            _scheduler.packet_weight[ATTITUDE] = 80;    // attitude
        } else {
            _scheduler.packet_weight[TEXT] = 5000;      // messages
            _scheduler.packet_weight[ATTITUDE] = 45;    // attitude
        }
    }
#else   //HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    if (!queue_empty) {
        _scheduler.packet_weight[TEXT] = 45;     // messages
        _scheduler.packet_weight[ATTITUDE] = 80;     // attitude
    } else {
        _scheduler.packet_weight[TEXT] = 5000;   // messages
        _scheduler.packet_weight[ATTITUDE] = 45;     // attitude
    }
#endif //HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    // when using fport raise user data priority if any packets are pending
    if (_use_external_data && _sport_push_buffer.pending) {
        _scheduler.packet_weight[UDATA] = 250;
    } else {
        _scheduler.packet_weight[UDATA] = 5000;   // user data
    }
}

// WFQ scheduler
bool AP_Frsky_SPort_Passthrough::is_packet_ready(uint8_t idx, bool queue_empty)
{
    bool packet_ready = false;
    switch (idx) {
    case TEXT:
        packet_ready = !queue_empty;
        break;
    case GPS_LAT:
    case GPS_LON:
        // force gps coords to use default sensor ID, always send when used with external data
        packet_ready = _use_external_data || (_passthrough.new_byte == downlink_sensor_id);
        break;
    case AP_STATUS:
        packet_ready = gcs().vehicle_initialised();
        break;
    case BATT_2:
        packet_ready = AP::battery().num_instances() > 1;
        break;
    case RPM:
        {
            packet_ready = false;
#if AP_RPM_ENABLED
            const AP_RPM *rpm = AP::rpm();
            if (rpm == nullptr) {
                break;
            }
            packet_ready = rpm->num_sensors() > 0;
#endif
        }
        break;
    case TERRAIN:
        {
            packet_ready = false;
#if AP_TERRAIN_AVAILABLE
            const AP_Terrain *terrain = AP::terrain();
            packet_ready = terrain && terrain->enabled();
#endif
        }
        break;
    case WIND:
#if !APM_BUILD_TYPE(APM_BUILD_Rover)
    {
        float a;
        WITH_SEMAPHORE(AP::ahrs().get_semaphore());
        if (AP::ahrs().airspeed_estimate_true(a)) {
            // if we have an airspeed estimate then we have a valid wind estimate
            packet_ready = true;
        }
    }
#else
    {
        const AP_WindVane* windvane = AP_WindVane::get_singleton();
        packet_ready = windvane != nullptr && windvane->enabled();
    }
#endif
        break;
    case WAYPOINT:
        {
            const AP_Mission *mission = AP::mission();
            packet_ready = mission != nullptr && mission->get_current_nav_index() > 0;
        }
        break;
    case UDATA:
        // when using fport user data is sent by scheduler
        // when using sport user data is sent responding to custom polling
        packet_ready = _use_external_data && _sport_push_buffer.pending;
        break;
#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    case MAV:
        packet_ready = !_SPort_bidir.tx_packet_queue.is_empty();
        break;
#endif //HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    default:
        packet_ready = true;
        break;
    }

    return packet_ready;
}

/*
 * WFQ scheduler
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
void AP_Frsky_SPort_Passthrough::process_packet(uint8_t idx)
{
    // send packet
    switch (idx) {
    case TEXT: // 0x5000 status text
        if (get_next_msg_chunk()) {
            send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID, _msg_chunk.chunk);
        }
        break;
    case ATTITUDE: // 0x5006 Attitude and range
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+6, calc_attiandrng());
        break;
    case GPS_LAT: // 0x800 GPS lat
        // sample both lat and lon at the same time
        send_sport_frame(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, calc_gps_latlng(_passthrough.send_latitude)); // gps latitude or longitude
        _passthrough.gps_lng_sample = calc_gps_latlng(_passthrough.send_latitude);
        // force the scheduler to select GPS lon as packet that's been waiting the most
            // this guarantees that lat and lon are sent as consecutive packets
        _scheduler.packet_timer[GPS_LON] = _scheduler.packet_timer[GPS_LAT] - 10000;
        break;
    case GPS_LON: // 0x800 GPS lon
        send_sport_frame(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, _passthrough.gps_lng_sample); // gps longitude
        break;
    case VEL_YAW: // 0x5005 Vel and Yaw
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+5, calc_velandyaw());
        break;
    case AP_STATUS: // 0x5001 AP status
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+1, calc_ap_status());
        break;
    case GPS_STATUS: // 0x5002 GPS Status
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+2, calc_gps_status());
        break;
    case HOME: // 0x5004 Home
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+4, calc_home());
        break;
    case BATT_2: // 0x5008 Battery 2 status
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+8, calc_batt(1));
        break;
    case BATT_1: // 0x5003 Battery 1 status
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+3, calc_batt(0));
        break;
    case PARAM: // 0x5007 parameters
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+7, calc_param());
        break;
    case RPM: // 0x500A rpm sensors 1 and 2
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+0x0A, calc_rpm());
        break;
    case TERRAIN: // 0x500B terrain data
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+0x0B, calc_terrain());
        break;
    case WIND: // 0x500C terrain data
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+0x0C, calc_wind());
        break;
    case WAYPOINT: // 0x500D waypoint data
        send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+0x0D, calc_waypoint());
        break;
    case UDATA: // user data
        {
            WITH_SEMAPHORE(_sport_push_buffer.sem);
            if (_use_external_data && _sport_push_buffer.pending) {
                send_sport_frame(_sport_push_buffer.packet.frame, _sport_push_buffer.packet.appid, _sport_push_buffer.packet.data);
                _sport_push_buffer.pending = false;
            }
        }
        break;
#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    case MAV: // mavlite
        process_tx_queue();
        break;
#endif //HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    }
}

/*
 * send telemetry data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
void AP_Frsky_SPort_Passthrough::send(void)
{
    const uint16_t numc = MIN(_port->available(), 1024U);

    // this is the constant for hub data frame
    if (_port->txspace() < 19) {
        return;
    }
    // keep only the last two bytes of the data found in the serial buffer, as we shouldn't respond to old poll requests
    uint8_t prev_byte = 0;
    for (uint16_t i = 0; i < numc; i++) {
        prev_byte = _passthrough.new_byte;
        _passthrough.new_byte = _port->read();
#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
        AP_Frsky_SPort::sport_packet_t sp;

        if (_sport_handler.process_byte(sp, _passthrough.new_byte)) {
            queue_rx_packet(sp);
        }
#endif //HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    }
    // check if we should respond to this polling byte
    if (prev_byte == FRAME_HEAD) {
        if (is_passthrough_byte(_passthrough.new_byte)) {
            run_wfq_scheduler();
        } else {
            // respond to custom user data polling
            WITH_SEMAPHORE(_sport_push_buffer.sem);
            if (_sport_push_buffer.pending && _passthrough.new_byte == _sport_push_buffer.packet.sensor) {
                send_sport_frame(_sport_push_buffer.packet.frame, _sport_push_buffer.packet.appid, _sport_push_buffer.packet.data);
                _sport_push_buffer.pending = false;
            }
        }
    }
}

/*
 * grabs one "chunk" (4 bytes) of the queued message to be transmitted
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
bool AP_Frsky_SPort_Passthrough::get_next_msg_chunk(void)
{
    if (!_statustext.available) {
        WITH_SEMAPHORE(_statustext.sem);
        if (!_statustext.queue.pop(_statustext.next)) {
            return false;
        }
        _statustext.available = true;
    }

    if (_msg_chunk.repeats == 0) { // if it's the first time get_next_msg_chunk is called for a given chunk
        uint8_t character = 0;
        _msg_chunk.chunk = 0; // clear the 4 bytes of the chunk buffer

        for (uint8_t i = 0; i < 4 && _msg_chunk.char_index < sizeof(_statustext.next.text); i++) {
            character = _statustext.next.text[_msg_chunk.char_index++];

            if (!character) {
                break;
            }

            _msg_chunk.chunk |= character << (3-i) * 8;
        }

        if (!character || (_msg_chunk.char_index == sizeof(_statustext.next.text))) { // we've reached the end of the message (string terminated by '\0' or last character of the string has been processed)
            _msg_chunk.char_index = 0; // reset index to get ready to process the next message
            // add severity which is sent as the MSB of the last three bytes of the last chunk (bits 24, 16, and 8) since a character is on 7 bits
            _msg_chunk.chunk |= (_statustext.next.severity & 0x4)<<21;
            _msg_chunk.chunk |= (_statustext.next.severity & 0x2)<<14;
            _msg_chunk.chunk |= (_statustext.next.severity & 0x1)<<7;
        }
    }

    // repeat each message chunk 3 times to ensure transmission
    // on slow links reduce the number of duplicate chunks
    uint8_t extra_chunks = 2;

    if (_scheduler.avg_packet_rate < 20) {
        // with 3 or more extra frsky sensors on the bus
        // send messages only once
        extra_chunks = 0;
    } else if (_scheduler.avg_packet_rate < 30) {
        // with 1 or 2 extra frsky sensors on the bus
        // send messages twice
        extra_chunks = 1;
    }

    if (_msg_chunk.repeats++ > extra_chunks ) {
        _msg_chunk.repeats = 0;
        if (_msg_chunk.char_index == 0) {
            // we're ready for the next message
            _statustext.available = false;
        }
    }
    return true;
}

/*
 * prepare parameter data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_param(void)
{
    uint8_t param_id = _paramID;    //cache it because it gets changed inside the switch
    uint32_t param_value = 0;

    switch (_paramID) {
    case NONE:
    case FRAME_TYPE:
        param_value = gcs().frame_type(); // see MAV_TYPE in Mavlink definition file common.h
        _paramID = BATT_CAPACITY_1;
        break;
    case BATT_CAPACITY_1:
        param_value = (uint32_t)roundf(AP::battery().pack_capacity_mah(0)); // battery pack capacity in mAh
        _paramID = AP::battery().num_instances() > 1 ? BATT_CAPACITY_2 : TELEMETRY_FEATURES;
        break;
    case BATT_CAPACITY_2:
        param_value = (uint32_t)roundf(AP::battery().pack_capacity_mah(1)); // battery pack capacity in mAh
        _paramID = TELEMETRY_FEATURES;
        break;
    case TELEMETRY_FEATURES:
#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
        BIT_SET(param_value,PassthroughFeatures::BIDIR);
#endif
#if AP_SCRIPTING_ENABLED
        BIT_SET(param_value,PassthroughFeatures::SCRIPTING);
#endif
        _paramID = FRAME_TYPE;
        break;
    }
    //Reserve first 8 bits for param ID, use other 24 bits to store parameter value
    return (param_id << PARAM_ID_OFFSET) | (param_value & PARAM_VALUE_LIMIT);
}

/*
 * prepare gps status data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_gps_status(void)
{
    const AP_GPS &gps = AP::gps();

    // number of GPS satellites visible (limit to 15 (0xF) since the value is stored on 4 bits)
    uint32_t gps_status = (gps.num_sats() < GPS_SATS_LIMIT) ? gps.num_sats() : GPS_SATS_LIMIT;
    // GPS receiver status (limit to 0-3 (0x3) since the value is stored on 2 bits: NO_GPS = 0, NO_FIX = 1, GPS_OK_FIX_2D = 2, GPS_OK_FIX_3D or GPS_OK_FIX_3D_DGPS or GPS_OK_FIX_3D_RTK_FLOAT or GPS_OK_FIX_3D_RTK_FIXED = 3)
    gps_status |= ((gps.status() < GPS_STATUS_LIMIT) ? gps.status() : GPS_STATUS_LIMIT)<<GPS_STATUS_OFFSET;
    // GPS horizontal dilution of precision in dm
    gps_status |= prep_number(roundf(gps.get_hdop() * 0.1f),2,1)<<GPS_HDOP_OFFSET;
    // GPS receiver advanced status (0: no advanced fix, 1: GPS_OK_FIX_3D_DGPS, 2: GPS_OK_FIX_3D_RTK_FLOAT, 3: GPS_OK_FIX_3D_RTK_FIXED)
    gps_status |= ((gps.status() > GPS_STATUS_LIMIT) ? gps.status()-GPS_STATUS_LIMIT : 0)<<GPS_ADVSTATUS_OFFSET;
    // Altitude MSL in dm
    const Location &loc = gps.location();
    gps_status |= prep_number(roundf(loc.alt * 0.1f),2,2)<<GPS_ALTMSL_OFFSET;
    return gps_status;
}

/*
 * prepare battery data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_batt(uint8_t instance)
{
    const AP_BattMonitor &_battery = AP::battery();

    float current, consumed_mah;
    if (!_battery.current_amps(current, instance)) {
        current = 0;
    }
    if (!_battery.consumed_mah(consumed_mah, instance)) {
        consumed_mah = 0;
    }

    // battery voltage in decivolts, can have up to a 12S battery (4.25Vx12S = 51.0V)
    uint32_t batt = (((uint16_t)roundf(_battery.voltage(instance) * 10.0f)) & BATT_VOLTAGE_LIMIT);
    // battery current draw in deciamps
    batt |= prep_number(roundf(current * 10.0f), 2, 1)<<BATT_CURRENT_OFFSET;
    // battery current drawn since power on in mAh (limit to 32767 (0x7FFF) since value is stored on 15 bits)
    batt |= ((consumed_mah < BATT_TOTALMAH_LIMIT) ? ((uint16_t)roundf(consumed_mah) & BATT_TOTALMAH_LIMIT) : BATT_TOTALMAH_LIMIT)<<BATT_TOTALMAH_OFFSET;
    return batt;
}

/*
 * true if we need to respond to the last polling byte
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
bool AP_Frsky_SPort_Passthrough::is_passthrough_byte(const uint8_t byte) const
{
#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
    if( byte == _SPort_bidir.downlink1_sensor_id || byte == _SPort_bidir.downlink2_sensor_id ) {
        return true;
    }
#endif
    return byte == downlink_sensor_id;
}

/*
 * prepare various autopilot status data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_ap_status(void)
{
    // IMU temperature: offset -19, 0 means temp =< 19°, 63 means temp => 82°
    uint8_t imu_temp = 0;
#if AP_INERTIALSENSOR_ENABLED
    imu_temp = (uint8_t) roundf(constrain_float(AP::ins().get_temperature(0), AP_IMU_TEMP_MIN, AP_IMU_TEMP_MAX) - AP_IMU_TEMP_MIN);
#endif

    // control/flight mode number (limit to 31 (0x1F) since the value is stored on 5 bits)
    uint32_t ap_status = (uint8_t)((gcs().custom_mode()+1) & AP_CONTROL_MODE_LIMIT);
    // simple/super simple modes flags
    ap_status |= (uint8_t)(gcs().simple_input_active())<<AP_SIMPLE_OFFSET;
    ap_status |= (uint8_t)(gcs().supersimple_input_active())<<AP_SSIMPLE_OFFSET;
    // is_flying flag
    ap_status |= (uint8_t)(AP_Notify::flags.flying) << AP_FLYING_OFFSET;
    // armed flag
    ap_status |= (uint8_t)(AP_Notify::flags.armed)<<AP_ARMED_OFFSET;
    // battery failsafe flag
    ap_status |= (uint8_t)(AP_Notify::flags.failsafe_battery)<<AP_BATT_FS_OFFSET;
    // bad ekf flag
    ap_status |= (uint8_t)(AP_Notify::flags.ekf_bad)<<AP_EKF_FS_OFFSET;
    // generic failsafe
    ap_status |= (uint8_t)(AP_Notify::flags.failsafe_battery||AP_Notify::flags.failsafe_ekf||AP_Notify::flags.failsafe_gcs||AP_Notify::flags.failsafe_radio)<<AP_FS_OFFSET;
#if AP_FENCE_ENABLED
    // fence status
    AC_Fence *fence = AP::fence();
    if (fence != nullptr) {
        ap_status |= (uint8_t)(fence->enabled() && fence->present()) << AP_FENCE_PRESENT_OFFSET;
        ap_status |= (uint8_t)(fence->get_breaches()>0) << AP_FENCE_BREACH_OFFSET;
    }
#endif
    // signed throttle [-100,100] scaled down to [-63,63] on 7 bits, MSB for sign + 6 bits for 0-63
    ap_status |= prep_number(gcs().get_hud_throttle()*0.63, 2, 0)<<AP_THROTTLE_OFFSET;
    // IMU temperature
    ap_status |= imu_temp << AP_IMU_TEMP_OFFSET;
    return ap_status;
}

/*
 * prepare home position related data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_home(void)
{
    uint32_t home = 0;
    Location loc;
    Location home_loc;
    bool got_position = false;
    float _relative_home_altitude = 0;

    {
        AP_AHRS &_ahrs = AP::ahrs();
        WITH_SEMAPHORE(_ahrs.get_semaphore());
        got_position = _ahrs.get_location(loc);
        home_loc = _ahrs.get_home();
    }

    if (got_position) {
        // check home_loc is valid
        if (home_loc.lat != 0 || home_loc.lng != 0) {
            // distance between vehicle and home_loc in meters
            home = prep_number(roundf(home_loc.get_distance(loc)), 3, 2);
            // angle from front of vehicle to the direction of home_loc in 3 degree increments (just in case, limit to 127 (0x7F) since the value is stored on 7 bits)
            home |= (((uint8_t)roundf(loc.get_bearing_to(home_loc) * 0.00333f)) & HOME_BEARING_LIMIT)<<HOME_BEARING_OFFSET;
        }
        // altitude between vehicle and home_loc
        _relative_home_altitude = loc.alt;
        if (!loc.relative_alt) {
            // loc.alt has home altitude added, remove it
            _relative_home_altitude -= home_loc.alt;
        }
    }
    // altitude above home in decimeters
    home |= prep_number(roundf(_relative_home_altitude * 0.1f), 3, 2)<<HOME_ALT_OFFSET;
    return home;
}

/*
 * prepare velocity and yaw data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_velandyaw(void)
{
    float vspd = AP_RCTelemetry::get_vspeed_ms();
    // vertical velocity in dm/s
    uint32_t velandyaw = prep_number(roundf(vspd * 10), 2, 1);
    float airspeed_m;       // m/s
    float hspeed_m;         // m/s
    bool airspeed_estimate_true;
    AP_AHRS &_ahrs = AP::ahrs();
    {
        WITH_SEMAPHORE(_ahrs.get_semaphore());
        hspeed_m = _ahrs.groundspeed(); // default is to use groundspeed
        airspeed_estimate_true = AP::ahrs().airspeed_estimate_true(airspeed_m);
    }
    bool option_airspeed_enabled = (_frsky_parameters->_options & frsky_options_e::OPTION_AIRSPEED_AND_GROUNDSPEED) != 0;
    // airspeed estimate + airspeed option disabled (default) => send airspeed (we give priority to airspeed over groundspeed)
    // airspeed estimate + airspeed option enabled => alternate airspeed/groundspeed, i.e send airspeed only when _passthrough.send_airspeed==true
    if (airspeed_estimate_true && (!option_airspeed_enabled || _passthrough.send_airspeed)) {
        hspeed_m = airspeed_m;
    }
    // horizontal velocity in dm/s
    velandyaw |= prep_number(roundf(hspeed_m * 10), 2, 1)<<VELANDYAW_XYVEL_OFFSET;
    // yaw from [0;36000] centidegrees to .2 degree increments [0;1800] (just in case, limit to 2047 (0x7FF) since the value is stored on 11 bits)
    velandyaw |= ((uint16_t)roundf(_ahrs.yaw_sensor * 0.05f) & VELANDYAW_YAW_LIMIT)<<VELANDYAW_YAW_OFFSET;
    // flag the airspeed bit if required
    if (airspeed_estimate_true && option_airspeed_enabled && _passthrough.send_airspeed) {
        velandyaw |= 1U<<VELANDYAW_ARSPD_OFFSET;
    }
    // toggle air/ground speed selector
    _passthrough.send_airspeed = !_passthrough.send_airspeed;
    return velandyaw;
}

/*
 * prepare attitude (roll, pitch) and range data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_attiandrng(void)
{
#if AP_RANGEFINDER_ENABLED
    const RangeFinder *_rng = RangeFinder::get_singleton();
#endif

    float roll;
    float pitch;
    AP::vehicle()->get_osd_roll_pitch_rad(roll,pitch);
    // roll from [-18000;18000] centidegrees to unsigned .2 degree increments [0;1800] (just in case, limit to 2047 (0x7FF) since the value is stored on 11 bits)
    uint32_t attiandrng = ((uint16_t)roundf((roll * RAD_TO_DEG * 100 + 18000) * 0.05f) & ATTIANDRNG_ROLL_LIMIT);
    // pitch from [-9000;9000] centidegrees to unsigned .2 degree increments [0;900] (just in case, limit to 1023 (0x3FF) since the value is stored on 10 bits)
    attiandrng |= ((uint16_t)roundf((pitch * RAD_TO_DEG * 100 + 9000) * 0.05f) & ATTIANDRNG_PITCH_LIMIT)<<ATTIANDRNG_PITCH_OFFSET;
    // rangefinder measurement in cm
#if AP_RANGEFINDER_ENABLED
    attiandrng |= prep_number(_rng ? _rng->distance_cm_orient(ROTATION_PITCH_270) : 0, 3, 1)<<ATTIANDRNG_RNGFND_OFFSET;
#else
    attiandrng |= prep_number(0, 3, 1)<<ATTIANDRNG_RNGFND_OFFSET;
#endif
    return attiandrng;
}

/*
 * prepare rpm for sensors 1 and 2
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_rpm(void)
{
#if AP_RPM_ENABLED
    const AP_RPM *ap_rpm = AP::rpm();
    if (ap_rpm == nullptr) {
        return 0;
    }
    uint32_t value = 0;
    // we send: rpm_value*0.1 as 16 bits signed
    float rpm;
    // bits 0-15 for rpm 0
    if (ap_rpm->get_rpm(0,rpm)) {
        value |= (int16_t)roundf(rpm * 0.1);
    }
    // bits 16-31 for rpm 1
    if (ap_rpm->get_rpm(1,rpm)) {
        value |= (int16_t)roundf(rpm * 0.1) << 16;
    }
    return value;
#else
    return 0;
#endif
}

/*
 * prepare terrain data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_terrain(void)
{
    uint32_t value = 0;
#if AP_TERRAIN_AVAILABLE
    AP_Terrain *terrain = AP::terrain();
    if (terrain == nullptr || !terrain->enabled()) {
        return value;
    }
    float height_above_terrain;
    if (terrain->height_above_terrain(height_above_terrain, true)) {
        // vehicle height above terrain
        value |= prep_number(roundf(height_above_terrain * 10), 3, 2);
    }
    // terrain unhealthy flag
    value |= (uint8_t)(terrain->status() == AP_Terrain::TerrainStatus::TerrainStatusUnhealthy) << TERRAIN_UNHEALTHY_OFFSET;
#endif
    return value;
}

/*
 * prepare wind data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 * wind direction = 0 means North
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_wind(void)
{
#if !APM_BUILD_TYPE(APM_BUILD_Rover)
    Vector3f v;
    {
        AP_AHRS &ahrs = AP::ahrs();
        WITH_SEMAPHORE(ahrs.get_semaphore());
        v = ahrs.wind_estimate();
    }
    // wind angle in 3 degree increments 0,360 (unsigned)
    uint32_t value = prep_number(roundf(wrap_360(degrees(atan2f(-v.y, -v.x))) * (1.0f/3.0f)), 2, 0);
    // wind speed in dm/s
    value |= prep_number(roundf(v.length() * 10), 2, 1) << WIND_SPEED_OFFSET;
#else
    const AP_WindVane* windvane = AP_WindVane::get_singleton();
    uint32_t value = 0;
    if (windvane != nullptr && windvane->enabled()) {
        // true wind angle in 3 degree increments 0,360 (unsigned)
        value = prep_number(roundf(wrap_360(degrees(windvane->get_true_wind_direction_rad())) * (1.0f/3.0f)), 2, 0);
        // true wind speed in dm/s
        value |= prep_number(roundf(windvane->get_true_wind_speed() * 10), 2, 1) << WIND_SPEED_OFFSET;
        // apparent wind angle in 3 degree increments -180,180 (signed)
        value |= prep_number(roundf(degrees(windvane->get_apparent_wind_direction_rad()) * (1.0f/3.0f)), 2, 0) << WIND_APPARENT_ANGLE_OFFSET;
        // apparent wind speed in dm/s
        value |= prep_number(roundf(windvane->get_apparent_wind_speed() * 10), 2, 1) << WIND_APPARENT_SPEED_OFFSET;
    }
#endif
    return value;
}
 /*
 * prepare waypoint data
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
uint32_t AP_Frsky_SPort_Passthrough::calc_waypoint(void)
{
    const AP_Mission *mission = AP::mission();
    const AP_Vehicle *vehicle = AP::vehicle();
    if (mission == nullptr || vehicle == nullptr) {
        return 0U;
    }
    float wp_distance;
    if (!vehicle->get_wp_distance_m(wp_distance)) {
        return 0U;
    }
    float angle;
    if (!vehicle->get_wp_bearing_deg(angle)) {
        return 0U;
    }
    // waypoint current nav index
    uint32_t value = MIN(mission->get_current_nav_index(), WP_NUMBER_LIMIT);
    // distance to next waypoint
    value |= prep_number(wp_distance, 3, 2) << WP_DISTANCE_OFFSET;
    // bearing encoded in 3 degrees increments
    value |= ((uint8_t)roundf(wrap_360(angle) * 0.333f)) << WP_BEARING_OFFSET;
    return value;
}

/*
  fetch Sport data for an external transport, such as FPort or crossfire
  Note: we need to create a packet array with unique packet types
  For very big frames we might have to relax the "unique packet type per frame"
  constraint in order to maximize bandwidth usage
 */
bool AP_Frsky_SPort_Passthrough::get_telem_data(sport_packet_t* packet_array, uint8_t &packet_count, const uint8_t max_size)
{
    if (!_use_external_data) {
        return false;
    }

    uint8_t idx = 0;

    // max_size >= WFQ_LAST_ITEM
    // get a packet per enabled type
    if (max_size >= WFQ_LAST_ITEM) {
        for (uint8_t i=0; i<WFQ_LAST_ITEM; i++) {
            if (process_scheduler_entry(i)) {
                if (external_data.pending) {
                    packet_array[idx].frame = external_data.packet.frame;
                    packet_array[idx].appid = external_data.packet.appid;
                    packet_array[idx].data = external_data.packet.data;
                    idx++;
                    external_data.pending = false;
                }
            }
        }
    } else {
        // max_size < WFQ_LAST_ITEM
        // call run_wfq_scheduler(false) enough times to create a packet of up to max_size unique elements
        uint32_t item_mask = 0;
        for (uint8_t i=0; i<max_size; i++) {
            // call the scheduler with the shaper "disabled"
            const uint8_t item = run_wfq_scheduler(false);
            if (!BIT_IS_SET(item_mask, item) && external_data.pending) {
                // ok got some data, flip the bitmask bit to prevent adding the same packet type more than once
                BIT_SET(item_mask, item);
                packet_array[idx].frame = external_data.packet.frame;
                packet_array[idx].appid = external_data.packet.appid;
                packet_array[idx].data = external_data.packet.data;
                idx++;
                external_data.pending = false;
            }
        }
    }
    packet_count = idx;
    return idx > 0;
}

#if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
/*
  allow external transports (e.g. FPort), to supply telemetry data
 */
bool AP_Frsky_SPort_Passthrough::set_telem_data(const uint8_t frame, const uint16_t appid, const uint32_t data)
{
    // queue only Uplink packets
    if (frame == SPORT_UPLINK_FRAME || frame == SPORT_UPLINK_FRAME_RW) {
        const AP_Frsky_SPort::sport_packet_t sp {
            { 0x00,   // this is ignored by process_sport_rx_queue() so no need for a real sensor ID
            frame,
            appid,
            data }
        };

        _SPort_bidir.rx_packet_queue.push_force(sp);
        return true;
    }
    return false;
}

/*
 * Queue uplink packets in the sport rx queue
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
void AP_Frsky_SPort_Passthrough::queue_rx_packet(const AP_Frsky_SPort::sport_packet_t packet)
{
    // queue only Uplink packets
    if (packet.sensor == _SPort_bidir.uplink_sensor_id && packet.frame == SPORT_UPLINK_FRAME) {
        _SPort_bidir.rx_packet_queue.push_force(packet);
    }
}

/*
 * Extract up to 1 mavlite message from the sport rx packet queue
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
void AP_Frsky_SPort_Passthrough::process_rx_queue()
{
    AP_Frsky_SPort::sport_packet_t packet;
    uint8_t loop_count = 0; // prevent looping forever
    while (_SPort_bidir.rx_packet_queue.pop(packet) && loop_count++ < MAVLITE_MSG_SPORT_PACKETS_COUNT(MAVLITE_MAX_PAYLOAD_LEN)) {
        AP_Frsky_MAVlite_Message rxmsg;

        if (sport_to_mavlite.process(rxmsg, packet)) {
            mavlite.process_message(rxmsg);
            break; // process only 1 mavlite message each call
        }
    }
}

/*
 * Process the sport tx queue
 * pop and send 1 sport packet
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
void AP_Frsky_SPort_Passthrough::process_tx_queue()
{
    AP_Frsky_SPort::sport_packet_t packet;

    if (!_SPort_bidir.tx_packet_queue.peek(packet)) {
        return;
    }

    // when using fport repeat each packet to account for
    // fport packet loss (around 15%)
    if (!_use_external_data || _SPort_bidir.tx_packet_duplicates++ == SPORT_TX_PACKET_DUPLICATES) {
        _SPort_bidir.tx_packet_queue.pop();
        _SPort_bidir.tx_packet_duplicates = 0;
    }

    send_sport_frame(SPORT_DOWNLINK_FRAME, packet.appid, packet.data);
}

/*
 * Send a mavlite message
 * Message is chunked in sport packets pushed in the tx queue
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
bool AP_Frsky_SPort_Passthrough::send_message(const AP_Frsky_MAVlite_Message &txmsg)
{
    return mavlite_to_sport.process(_SPort_bidir.tx_packet_queue, txmsg);
}
#endif //HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
/*
 * Utility method to apply constraints in changing sensor id values
 * for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
 */
void AP_Frsky_SPort_Passthrough::set_sensor_id(AP_Int8 param_idx, uint8_t &sensor)
{
    int8_t idx = param_idx.get();

    if (idx == -1) {
        // disable this sensor
        sensor = 0xFF;
        return;
    }
    sensor = calc_sensor_id(idx);
}

namespace AP
{
AP_Frsky_SPort_Passthrough *frsky_passthrough_telem()
{
    return AP_Frsky_SPort_Passthrough::get_singleton();
}
};

#endif  // AP_FRSKY_SPORT_PASSTHROUGH_ENABLED