/* Audio Library for Teensy 3.X * Copyright (c) 2017, Paul Stoffregen, paul@pjrc.com * * Development of this audio library was funded by PJRC.COM, LLC by sales of * Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop * open source software by purchasing Teensy or other PJRC products. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice, development funding notice, and this permission * notice shall be included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #ifndef synth_pwm_h_ #define synth_pwm_h_ #include #include #include class AudioSynthWaveformPWM : public AudioStream { public: AudioSynthWaveformPWM() : AudioStream(1, inputQueueArray), magnitude(0), elapsed(0) {} void frequency(float freq) { if (freq < 1.0) freq = 1.0; else if (freq > AUDIO_SAMPLE_RATE_EXACT/4) freq = AUDIO_SAMPLE_RATE_EXACT/4; //phase_increment = freq * (4294967296.0 / AUDIO_SAMPLE_RATE_EXACT); duration = (AUDIO_SAMPLE_RATE_EXACT * 65536.0 + freq) / (freq * 2.0); } void amplitude(float n) { if (n < 0) n = 0; else if (n > 1.0) n = 1.0; magnitude = n * 32767.0; } virtual void update(void); private: uint32_t duration; // samples per half cycle (when 50% duty) * 65536 audio_block_t *inputQueueArray[1]; int32_t magnitude; uint32_t elapsed; }; #endif