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/* mbed PwmOutSpeaker Library
 * Copyright (C) 2016 dkato
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef PWMOUT_SPEAKER_H
#define PWMOUT_SPEAKER_H

#include "mbed.h"
#include "rtos.h"

/** PwmOutSpeaker class
*
*/
class PwmOutSpeaker {
public:
    /** Create a PwmOutSpeaker
     * 
     * @param pwm_l  
     * @param pwm_r  
     */
    PwmOutSpeaker(PinName pwm_l, PinName pwm_r);

    /** Set I2S interface bit length and mode
     *
     * @param length Set bit length to 8 or 16 bits
     * @return true = success, false = failure
     */
    bool format(char length, char ch = 2);

    /** Set sample frequency
     *
     * @param frequency Sample frequency of data in Hz
     * @return true = success, false = failure
     * 
     * Supports the following frequencies: 8kHz, 8.021kHz, 32kHz, 44.1kHz, 48kHz
     * Default is 44.1kHz
     */
    bool frequency(int hz);

    /** Enqueue asynchronous write request
     *
     * @param p_data Location of the data
     * @param data_size Number of bytes to write
     * @return Number of bytes written on success. negative number on error.
     */
    int write(uint8_t * const p_data, uint32_t data_size);

    /** Volume control
     *
     * @param volume Speaker volume
     * @return Returns "true" for success, "false" if parameters are out of range
     * Parameters accept a value, where 0.0 <= parameter <= 1.0 (1.0 = default)
     */
    bool outputVolume(float volume);

private:
    #define WRITE_BUFF_SIZE    (1024 * 4)
    #define MSK_RING_BUFF      (WRITE_BUFF_SIZE - 1)

    PwmOut   _speaker_l;
    PwmOut   _speaker_r;
    Ticker   _timer;
    int      _channel;
    int      _length;
    int      _hz_multi;
    int      _data_cnt;
    bool     _playing;
    volatile uint32_t _bottom;
    volatile uint32_t _top;
    float    _speaker_vol;
    float    _pwm_duty_buf[WRITE_BUFF_SIZE];

    void sound_out(void);
};

#endif // PWMOUT_SPEAKER_H