PWM drives the speaker.
PwmOutSpeaker.cpp
- Committer:
- dkato
- Date:
- 2018-07-24
- Revision:
- 3:37a886d77bae
- Parent:
- 2:436529700217
File content as of revision 3:37a886d77bae:
/* 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, 1.0f); format(16); frequency(44100); } bool PwmOutSpeaker::format(char length) { switch (length) { case 8: case 16: break; default: return false; } _length = length; _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(void * const p_data, uint32_t data_size, const rbsp_data_conf_t * const p_data_conf) { int data_num; int i = 0; float wk_vol_l; float wk_ofs_l; float wk_vol_r; float wk_ofs_r; 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 += 2; } else { _data_cnt = 0; while (((_bottom + 2) & MSK_RING_BUFF) == _top) { Thread::wait(1); } wk_vol_l = _speaker_vol_l; wk_ofs_l = (1.0f - wk_vol_l) / 2; wk_vol_r = _speaker_vol_r; wk_ofs_r = (1.0f - wk_vol_r) / 2; if (_length == 8) { _pwm_duty_buf[_bottom] = ((float)((uint8_t *)p_data)[i++] / (float)0xff) * wk_vol_l + wk_ofs_l; _pwm_duty_buf[_bottom + 1] = ((float)((uint8_t *)p_data)[i++] / (float)0xff) * wk_vol_r + wk_ofs_r; } else { _pwm_duty_buf[_bottom] = ((float)(((int16_t *)p_data)[i++] + 0x8000) / (float)0xffff) * wk_vol_l + wk_ofs_l; _pwm_duty_buf[_bottom + 1] = ((float)(((int16_t *)p_data)[i++] + 0x8000) / (float)0xffff) * wk_vol_r + wk_ofs_r; } _bottom = (_bottom + 2) & MSK_RING_BUFF; } } if (p_data_conf != NULL) { return data_size; } if (p_data_conf->p_notify_func != NULL) { p_data_conf->p_notify_func(p_data, data_size, p_data_conf->p_app_data); } return 0; } bool PwmOutSpeaker::outputVolume(float leftVolumeOut, float rightVolumeOut) { if ((leftVolumeOut < 0.0) || (leftVolumeOut > 1.0)) { return false; } if ((rightVolumeOut < 0.0) || (rightVolumeOut > 1.0)) { return false; } _speaker_vol_l = leftVolumeOut; _speaker_vol_r = rightVolumeOut; 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 } }