ardupilot/libraries/AP_RangeFinder/AP_RangeFinder_TOFSenseP_CAN.cpp

#include "AP_RangeFinder_config.h"

#if AP_RANGEFINDER_TOFSENSEP_CAN_ENABLED

#include "AP_RangeFinder_TOFSenseP_CAN.h"
#include <AP_BoardConfig/AP_BoardConfig.h>
#include <AP_HAL/utility/sparse-endian.h>
#include <AP_HAL/AP_HAL.h>

RangeFinder_MultiCAN *AP_RangeFinder_TOFSenseP_CAN::multican_TOFSenseP;

/*
  constructor
 */
AP_RangeFinder_TOFSenseP_CAN::AP_RangeFinder_TOFSenseP_CAN(RangeFinder::RangeFinder_State &_state, AP_RangeFinder_Params &_params) :
    AP_RangeFinder_Backend_CAN(_state, _params)
{
    if (multican_TOFSenseP == nullptr) {
        multican_TOFSenseP = new RangeFinder_MultiCAN(AP_CAN::Protocol::TOFSenseP, "TOFSenseP MultiCAN");
        if (multican_TOFSenseP == nullptr) {
            AP_BoardConfig::allocation_error("Rangefinder_MultiCAN");
        }
    }

    {
        // add to linked list of drivers
        WITH_SEMAPHORE(multican_TOFSenseP->sem);
        auto *prev = multican_TOFSenseP->drivers;
        next = prev;
        multican_TOFSenseP->drivers = this;
    }
}


// handler for incoming frames. These come in at 10-30Hz
bool AP_RangeFinder_TOFSenseP_CAN::handle_frame(AP_HAL::CANFrame &frame)
{
    WITH_SEMAPHORE(_sem);
    const uint32_t id = frame.id - 0x200U;

    if (!is_correct_id(id)) {
        return false;
    }

    const int32_t dist_mm = (int32_t)(frame.data[0] << 8U | frame.data[1] << 16U | frame.data[2] << 24U) >> 8;
    const uint8_t status = frame.data[3];
    const uint16_t snr = le16toh_ptr(&frame.data[4]);

    if ((snr_min != 0 && snr < uint16_t(snr_min.get())) || status > 0) {
        // too low signal strength or bad status
        return false;
    }

    accumulate_distance_m(dist_mm * 0.001);
    return true;
}

#endif  // AP_RANGEFINDER_TOFSenseP_CAN_ENABLED