ardupilot/libraries/AP_Notify/Buzzer.h

/*
  Buzzer driver
*/
/*
   This program 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 program 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/>.
 */
#pragma once

#include <AP_HAL/AP_HAL.h>

#if CONFIG_HAL_BOARD == HAL_BOARD_VRBRAIN
 # define BUZZER_PIN    32
#else
 # define BUZZER_PIN    0       // pin undefined on other boards
#endif

#define BUZZER_ARMING_BUZZ_MS   3000    // arming buzz length in milliseconds (i.e. 3 seconds)

#include "NotifyDevice.h"

class Buzzer: public NotifyDevice
{
public:
    /// Constructor
    Buzzer() :
        _counter(0),
        _pattern(NONE),
        _pattern_counter(0),
        _arming_buzz_start_ms(0)
    {}

    /// init - initialise the buzzer
    bool init(void);

    /// update - updates buzzer according to timed_updated.  Should be called at 50Hz
    void update();

    /// on - turns the buzzer on or off
    void on(bool on_off);

    enum BuzzerPattern {
        NONE = 0,
        SINGLE_BUZZ = 1,
        DOUBLE_BUZZ = 2,
        GPS_GLITCH = 3, // not used
        ARMING_BUZZ = 4,
        BARO_GLITCH = 5,
        EKF_BAD = 6
    };

    /// play_pattern - plays the defined buzzer pattern
    void play_pattern(BuzzerPattern pattern_id);

private:

    /// buzzer_flag_type - bitmask of current state and ap_notify states we track
    struct buzzer_flag_type {
        uint8_t on                  : 1;    // 1 if the buzzer is currently on
        uint8_t arming              : 1;    // 1 if we are beginning the arming process
        uint8_t armed               : 1;    // 0 = disarmed, 1 = armed
        uint8_t failsafe_battery    : 1;    // 1 if battery failsafe has triggered
        uint8_t ekf_bad            : 1;    // 1 if ekf position has gone bad
    } _flags;

    uint8_t         _counter;           // reduces 50hz update down to 10hz for internal processing
    BuzzerPattern   _pattern;           // current pattern
    uint8_t         _pattern_counter;   // used to time on/off of current patter
    uint32_t        _arming_buzz_start_ms;  // arming_buzz start time in milliseconds
};