PwmOutSpeaker.cpp

00001 /* mbed PwmOutSpeaker Library
00002  * Copyright (C) 2016 dkato
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #include "PwmOutSpeaker.h"
00018 
00019 PwmOutSpeaker::PwmOutSpeaker(PinName pwm_l, PinName pwm_r) : 
00020  _speaker_l(NULL), _speaker_r(NULL), _audioThread(osPriorityHigh), _sound_out_req(0) {
00021     _bottom = 0;
00022     _top = 0;
00023     _playing = false;
00024     if (pwm_l != NC) {
00025         _speaker_l = new PwmOut(pwm_l);
00026     }
00027     if (pwm_r != NC) {
00028         _speaker_r = new PwmOut(pwm_r);
00029     }
00030     _audioThread.start(callback(this, &PwmOutSpeaker::audio_process));
00031     outputVolume(1.0f, 1.0f);
00032     format(16);
00033     frequency(44100);
00034 }
00035 
00036 PwmOutSpeaker::~PwmOutSpeaker() {
00037     if (_speaker_l != NULL) {
00038         delete _speaker_l;
00039     }
00040     if (_speaker_r != NULL) {
00041         delete _speaker_r;
00042     }
00043 }
00044 
00045 bool PwmOutSpeaker::format(char length) {
00046     switch (length) {
00047         case 8:
00048         case 16:
00049             break;
00050         default:
00051             return false;
00052     }
00053     _length = length;
00054     _data_cnt = 0;
00055     return true;
00056 }
00057 
00058 bool PwmOutSpeaker::frequency(int hz) {
00059     int wk_us;
00060 
00061     switch (hz) {
00062         case 48000:
00063             _hz_multi = 6;
00064             break;
00065         case 44100:
00066             _hz_multi = 5;
00067             break;
00068         case 32000:
00069             _hz_multi = 4;
00070             break;
00071         case 8021:
00072         case 8000:
00073             _hz_multi = 1;
00074             break;
00075         default:
00076             return false;
00077     }
00078     _playing = false;
00079     if (_speaker_l != NULL) {
00080         _speaker_l->write(0.5f);
00081         _speaker_l->period_us(10);  // 100kHz
00082     }
00083     if (_speaker_r != NULL) {
00084         _speaker_r->write(0.5f);
00085         _speaker_r->period_us(10);  // 100kHz
00086     }
00087     wk_us = (int)(1000000.0f / hz * _hz_multi + 0.5f);
00088     _timer.attach_us(Callback<void()>(this, &PwmOutSpeaker::sound_out), wk_us);
00089     _data_cnt = 0;
00090 
00091     return true;
00092 }
00093 
00094 int PwmOutSpeaker::write(void * const p_data, uint32_t data_size, const rbsp_data_conf_t * const p_data_conf) {
00095     int data_num;
00096     int i = 0;
00097     float wk_vol_l;
00098     float wk_ofs_l;
00099     float wk_vol_r;
00100     float wk_ofs_r;
00101 
00102     if (_length == 8) {
00103         data_num = data_size;
00104     } else {
00105         data_num = data_size / 2;
00106     }
00107     while (i < data_num) {
00108         if (_data_cnt < (_hz_multi - 1)) {
00109             _data_cnt++;
00110             i += 2;
00111         } else {
00112             _data_cnt = 0;
00113             while (((_bottom + 2) & MSK_RING_BUFF) == _top) {
00114                 ThisThread::sleep_for(1);
00115             }
00116 
00117             wk_vol_l = _speaker_vol_l;
00118             wk_ofs_l = (1.0f - wk_vol_l) / 2;
00119             wk_vol_r = _speaker_vol_r;
00120             wk_ofs_r = (1.0f - wk_vol_r) / 2;
00121             if (_length == 8) {
00122                 _pwm_duty_buf[_bottom] = ((float)((uint8_t *)p_data)[i++] / (float)0xff) * wk_vol_l + wk_ofs_l;
00123                 _pwm_duty_buf[_bottom + 1] = ((float)((uint8_t *)p_data)[i++] / (float)0xff) * wk_vol_r + wk_ofs_r;
00124             } else {
00125                 _pwm_duty_buf[_bottom] = ((float)(((int16_t *)p_data)[i++] + 0x8000) / (float)0xffff) * wk_vol_l + wk_ofs_l;
00126                 _pwm_duty_buf[_bottom + 1] = ((float)(((int16_t *)p_data)[i++] + 0x8000) / (float)0xffff) * wk_vol_r + wk_ofs_r;
00127             }
00128             _bottom = (_bottom + 2) & MSK_RING_BUFF;
00129         }
00130     }
00131 
00132     if (p_data_conf != NULL) {
00133         return data_size;
00134     }
00135 
00136     if (p_data_conf->p_notify_func != NULL) {
00137         p_data_conf->p_notify_func(p_data, data_size, p_data_conf->p_app_data);
00138     }
00139 
00140     return 0;
00141 }
00142 
00143 bool PwmOutSpeaker::outputVolume(float leftVolumeOut, float rightVolumeOut) {
00144     if ((leftVolumeOut < 0.0) || (leftVolumeOut > 1.0)) {
00145         return false;
00146     }
00147     if ((rightVolumeOut < 0.0) || (rightVolumeOut > 1.0)) {
00148         return false;
00149     }
00150     _speaker_vol_l  = leftVolumeOut;
00151     _speaker_vol_r  = rightVolumeOut;
00152     return true;
00153 }
00154 
00155 void PwmOutSpeaker::sound_out(void) {
00156     _sound_out_req.release();
00157 }
00158 
00159 void PwmOutSpeaker::audio_process() {
00160     while (true) {
00161         _sound_out_req.wait();
00162         if (_top != _bottom) {
00163             if (_speaker_l != NULL) {
00164                 _speaker_l->write(_pwm_duty_buf[_top + 0]);
00165             }
00166             if (_speaker_r != NULL) {
00167                 _speaker_r->write(_pwm_duty_buf[_top + 1]);
00168             }
00169             _top = (_top + 2) & MSK_RING_BUFF;
00170             _playing = true;
00171         } else if (_playing) {
00172             if (_speaker_l != NULL) {
00173                 _speaker_l->write(0.5f);
00174             }
00175             if (_speaker_r != NULL) {
00176                 _speaker_r->write(0.5f);
00177             }
00178             _playing = false;
00179         } else {
00180             // do nothing
00181         }
00182     }
00183 }
00184