linux_sbus.h

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 *
 *   Copyright (C) 2017 Mark Charl. All rights reserved.
 *   Copyright (C) 2017 Fan.zhang. All rights reserved.
 *   Copyright (C) 2017 PX4 Development Team. All rights reserved.
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#pragma once

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
/*For terminal I/O interfaces, termbits.h from asm-generic versions of functions guarantees non-standard communication (100Khz, Non-blocking), not guaranteed by termios.h*/
#include <asm-generic/termbits.h>
#include <errno.h>
#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
#include <px4_platform_common/defines.h>
#include <drivers/drv_hrt.h>
#include <uORB/uORB.h>
#include <uORB/topics/input_rc.h>
/* The interval between each frame is 4700us, do not change it. */
#define RCINPUT_MEASURE_INTERVAL_US 4700
/* define range mapping here, -+100% -> 1000..2000 */
#define SBUS_RANGE_MIN 200.0f
#define SBUS_RANGE_MAX 1800.0f
#define SBUS_TARGET_MIN 1000.0f
#define SBUS_TARGET_MAX 2000.0f
/* pre-calculate the floating point stuff as far as possible at compile time */
#define SBUS_SCALE_FACTOR ((SBUS_TARGET_MAX - SBUS_TARGET_MIN) / (SBUS_RANGE_MAX - SBUS_RANGE_MIN))
#define SBUS_SCALE_OFFSET (int)(SBUS_TARGET_MIN - (SBUS_SCALE_FACTOR * SBUS_RANGE_MIN + 0.5f))

namespace linux_sbus
{
class RcInput : public px4::ScheduledWorkItem
{
public:
    RcInput() :
        ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::hp_default),
        _shouldExit(false),
        _isRunning(false),
        _rcinput_pub(nullptr),
        _data { }, _sbusData {   0x0f, 0x01, 0x04, 0x20, 0x00,
                     0xff, 0x07, 0x40, 0x00, 0x02,
                     0x10, 0x80, 0x2c, 0x64, 0x21,
                     0x0b, 0x59, 0x08, 0x40, 0x00,
                     0x02, 0x10, 0x80, 0x00, 0x00   }
    { }
    ~RcInput()
    {
        ScheduleClear();
        _isRunning = false;
        close(_device_fd);
    }
    /** @return 0 on success, -errno on failure */
    int start(char *device, int channels);
    void stop();

    bool isRunning()
    {
        return _isRunning;
    }

private:
    void Run() override;
    void _measure();
    bool _shouldExit;
    bool _isRunning;
    orb_advert_t _rcinput_pub;
    struct input_rc_s _data;
    uint8_t _sbusData[25];
    int _channels;
    int _device_fd;  /** serial port device to read SBUS; */
    int _channels_data[16]; /** 16 channels support; */
    uint8_t _buffer[25];
    char _device[30];
    bool _failsafe;
    bool _rc_loss;
    int init();
};

static void usage(const char *reason);
static RcInput *rc_input = nullptr;
}
extern "C" __EXPORT int linux_sbus_main(int argc, char **argv);