ardupilot/libraries/AP_HAL/utility/RCOutput_Tap.h

/*
 * Copyright (c) 2016  PX4 Development Team. All rights reserved.
 * Copyright (C) 2017  Intel Corporation. All rights reserved.
 *
 * This file is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This file is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Implementation of TAP UART ESCs. Used the implementation from PX4 as a base
 * which is BSD-licensed:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name PX4 nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
#pragma once

#include <AP_HAL/Util.h>

namespace ap {

struct EscPacket;

class RCOutput_Tap : public AP_HAL::RCOutput {
public:
    void init() override;
    void set_freq(uint32_t chmask, uint16_t freq_hz) override;
    uint16_t get_freq(uint8_t ch) override;
    void enable_ch(uint8_t ch) override;
    void disable_ch(uint8_t ch) override;
    void write(uint8_t ch, uint16_t period_us) override;
    uint16_t read(uint8_t ch) override;
    void read(uint16_t *period_us, uint8_t len) override;

    void cork() override;
    void push() override;

private:
    static uint8_t _crc8_esc(uint8_t *p, uint8_t len);
    static uint8_t _crc_packet(EscPacket &p);

    static const uint8_t MAX_MOTORS = 4;

    int _send_packet(EscPacket &p);
    bool _uart_open();
    bool _uart_set_speed(int speed);
    void _uart_close();

    uint8_t _enabled_channels;
    bool _corking;
    bool _led_on;

    uint8_t _channels_count = MAX_MOTORS;

    uint16_t _period[MAX_MOTORS];
    uint32_t _last_led_update_msec;
    int _uart_fd = -1;
};

}