/* Audio Library for Teensy 3.X * Copyright (c) 2014, 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. */ #include "synth_waveform.h" #include "arm_math.h" #include "utility/dspinst.h" /******************************************************************/ // PAH 140415 - change sin to use Paul's interpolation which is much // faster than arm's sin function // PAH 140316 - fix calculation of sample (amplitude error) // PAH 140314 - change t_hi from int to float void AudioSynthWaveform::update(void) { audio_block_t *block; short *bp, *end; int32_t val1, val2, val3; uint32_t index, scale; // temporaries for TRIANGLE uint32_t mag; short tmp_amp; if(tone_amp == 0) return; block = allocate(); if (block) { bp = block->data; switch(tone_type) { case WAVEFORM_SINE: for(int i = 0;i < AUDIO_BLOCK_SAMPLES;i++) { // Calculate interpolated sin index = tone_phase >> 23; val1 = AudioWaveformSine[index]; val2 = AudioWaveformSine[index+1]; scale = (tone_phase >> 7) & 0xFFFF; val2 *= scale; val1 *= 0xFFFF - scale; val3 = (val1 + val2) >> 16; *bp++ = (short)((val3 * tone_amp) >> 15); // phase and incr are both unsigned 32-bit fractions tone_phase += tone_incr; // If tone_phase has overflowed, truncate the top bit if(tone_phase & 0x80000000)tone_phase &= 0x7fffffff; } break; case WAVEFORM_ARBITRARY: if (!arbdata) { release(block); return; } // len = 256 for (int i = 0; i < AUDIO_BLOCK_SAMPLES;i++) { index = tone_phase >> 23; val1 = *(arbdata + index); val2 = *(arbdata + ((index + 1) & 255)); scale = (tone_phase >> 7) & 0xFFFF; val2 *= scale; val1 *= 0xFFFF - scale; val3 = (val1 + val2) >> 16; *bp++ = (short)((val3 * tone_amp) >> 15); tone_phase += tone_incr; tone_phase &= 0x7fffffff; } break; case WAVEFORM_SQUARE: for(int i = 0;i < AUDIO_BLOCK_SAMPLES;i++) { if(tone_phase & 0x40000000)*bp++ = -tone_amp; else *bp++ = tone_amp; // phase and incr are both unsigned 32-bit fractions tone_phase += tone_incr; } break; case WAVEFORM_SAWTOOTH: for(int i = 0;i < AUDIO_BLOCK_SAMPLES;i++) { *bp++ = ((short)(tone_phase>>15)*tone_amp) >> 15; // phase and incr are both unsigned 32-bit fractions tone_phase += tone_incr; } break; case WAVEFORM_TRIANGLE: for(int i = 0;i < AUDIO_BLOCK_SAMPLES;i++) { if(tone_phase & 0x80000000) { // negative half-cycle tmp_amp = -tone_amp; } else { // positive half-cycle tmp_amp = tone_amp; } mag = tone_phase << 2; // Determine which quadrant if(tone_phase & 0x40000000) { // negate the magnitude mag = ~mag + 1; } *bp++ = ((short)(mag>>17)*tmp_amp) >> 15; tone_phase += 2*tone_incr; } break; case WAVEFORM_PULSE: for(int i = 0;i < AUDIO_BLOCK_SAMPLES;i++) { if(tone_phase < tone_width)*bp++ = -tone_amp; else *bp++ = tone_amp; tone_phase += tone_incr; } break; } if (tone_offset) { bp = block->data; end = bp + AUDIO_BLOCK_SAMPLES; do { val1 = *bp; *bp++ = signed_saturate_rshift(val1 + tone_offset, 16, 0); } while (bp < end); } transmit(block,0); release(block); } }