File content as of revision 2:436529700217:

/* 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.
 */

#include "PwmOutSpeaker.h"
#if defined(TARGET_RZ_A1H) || defined(TARGET_VK_RZ_A1H) || defined(TARGET_GR_LYCHEE)
#include "vfp_neon_push_pop.h"
#else
static void dummy_func(void) {}
#define __vfp_neon_push    dummy_func
#define __vfp_neon_pop     dummy_func
#endif

PwmOutSpeaker::PwmOutSpeaker(PinName pwm_l, PinName pwm_r) : _speaker_l(pwm_l), _speaker_r(pwm_r) {
    _bottom = 0;
    _top = 0;
    _playing = false;
    outputVolume(1.0f);
    format(16, 2);
    frequency(44100);
}

bool PwmOutSpeaker::format(char length, char ch) {
    if ((ch != 1) && (ch != 2)) {
        return false;
    }
    switch (length) {
        case 8:
        case 16:
            break;
        default:
            return false;
    }
    _length = length;
    _channel = ch;
    _data_cnt = 0;
    return true;
}

bool PwmOutSpeaker::frequency(int hz) {
    int wk_us;

    switch (hz) {
        case 48000:
            _hz_multi = 6;
            break;
        case 44100:
            _hz_multi = 5;
            break;
        case 32000:
            _hz_multi = 4;
            break;
        case 8021:
        case 8000:
            _hz_multi = 1;
            break;
        default:
            return false;
    }
    _speaker_l.write(0.5f);
    _speaker_r.write(0.5f);
    _playing = false;
    _speaker_l.period_us(10);  // 100kHz
    _speaker_r.period_us(10);  // 100kHz
    wk_us = (int)(1000000.0f / hz * _hz_multi + 0.5f);
    _timer.attach_us(Callback<void()>(this, &PwmOutSpeaker::sound_out), wk_us);
    _data_cnt = 0;

    return true;
}

int PwmOutSpeaker::write(uint8_t * const p_data, uint32_t data_size) {
    int data_num;
    int i = 0;
    float wk_vol;
    float wk_ofs;

    if (_length == 8) {
        data_num = data_size;
    } else {
        data_num = data_size / 2;
    }
    while (i < data_num) {
        if (_data_cnt < (_hz_multi - 1)) {
            _data_cnt++;
            i += _channel;
        } else {
            _data_cnt = 0;
            while (((_bottom + 2) & MSK_RING_BUFF) == _top) {
                Thread::wait(1);
            }
            wk_vol = _speaker_vol;
            wk_ofs = (1.0f - wk_vol) / 2;
            if (_length == 8) {
                _pwm_duty_buf[_bottom] = ((float)p_data[i++] / (float)0xff) * wk_vol + wk_ofs;
                if (_channel == 1) {
                    _pwm_duty_buf[_bottom + 1] = _pwm_duty_buf[_bottom];
                } else {
                    _pwm_duty_buf[_bottom + 1] = ((float)p_data[i++] / (float)0xff) * wk_vol + wk_ofs;
                }
            } else {
                _pwm_duty_buf[_bottom] = ((float)(((int16_t *)p_data)[i++] + 0x8000) / (float)0xffff) * wk_vol + wk_ofs;
                if (_channel == 1) {
                    _pwm_duty_buf[_bottom + 1] = _pwm_duty_buf[_bottom];
                } else {
                    _pwm_duty_buf[_bottom + 1] = ((float)(((int16_t *)p_data)[i++] + 0x8000) / (float)0xffff) * wk_vol + wk_ofs;
                }
            }
            _bottom = (_bottom + 2) & MSK_RING_BUFF;
        }
    }
    return 0;
}

bool PwmOutSpeaker::outputVolume(float volume) {
    if ((volume < 0.0) || (volume > 1.0)) {
        return false;
    }
    _speaker_vol  = volume;
    return true;
}

void PwmOutSpeaker::sound_out(void) {
    if (_top != _bottom) {
        __vfp_neon_push();
        _speaker_l.write(_pwm_duty_buf[_top + 0]);
        _speaker_r.write(_pwm_duty_buf[_top + 1]);
        __vfp_neon_pop();
        _top = (_top + 2) & MSK_RING_BUFF;
        _playing = true;
    } else if (_playing) {
        __vfp_neon_push();
        _speaker_l.write(0.5f);
        _speaker_r.write(0.5f);
        __vfp_neon_pop();
        _playing = false;
    } else {
        // do nothing
    }
}