/* Copyright 2019 Jack Humbert * Copyright 2020 JohSchneider * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #pragma once #ifndef A4 # define A4 PAL_LINE(GPIOA, 4) #endif #ifndef A5 # define A5 PAL_LINE(GPIOA, 5) #endif /** * Size of the dac_buffer arrays. All must be the same size. */ #define AUDIO_DAC_BUFFER_SIZE 256U /** * Highest value allowed sample value. * since the DAC is limited to 12 bit, the absolute max is 0xfff = 4095U; * lower values adjust the peak-voltage aka volume down. * adjusting this value has only an effect on a sample-buffer whose values are * are NOT pregenerated - see square-wave */ #ifndef AUDIO_DAC_SAMPLE_MAX # define AUDIO_DAC_SAMPLE_MAX 4095U #endif #if !defined(AUDIO_DAC_SAMPLE_RATE) && !defined(AUDIO_MAX_SIMULTANEOUS_TONES) && !defined(AUDIO_DAC_QUALITY_VERY_LOW) && !defined(AUDIO_DAC_QUALITY_LOW) && !defined(AUDIO_DAC_QUALITY_HIGH) && !defined(AUDIO_DAC_QUALITY_VERY_HIGH) # define AUDIO_DAC_QUALITY_SANE_MINIMUM #endif /** * These presets allow you to quickly switch between quality settings for * the DAC. The sample rate and maximum number of simultaneous tones roughly * has an inverse relationship - slightly higher sample rates may be possible. * * NOTE: a high sample-rate results in a higher cpu-load, which might lead to * (audible) discontinuities and/or starve other processes of cpu-time * (like RGB-led back-lighting, ...) */ #ifdef AUDIO_DAC_QUALITY_VERY_LOW # define AUDIO_DAC_SAMPLE_RATE 11025U # define AUDIO_MAX_SIMULTANEOUS_TONES 8 #endif #ifdef AUDIO_DAC_QUALITY_LOW # define AUDIO_DAC_SAMPLE_RATE 22050U # define AUDIO_MAX_SIMULTANEOUS_TONES 4 #endif #ifdef AUDIO_DAC_QUALITY_HIGH # define AUDIO_DAC_SAMPLE_RATE 44100U # define AUDIO_MAX_SIMULTANEOUS_TONES 2 #endif #ifdef AUDIO_DAC_QUALITY_VERY_HIGH # define AUDIO_DAC_SAMPLE_RATE 88200U # define AUDIO_MAX_SIMULTANEOUS_TONES 1 #endif #ifdef AUDIO_DAC_QUALITY_SANE_MINIMUM /* a sane-minimum config: with a trade-off between cpu-load and tone-range * * the (currently) highest defined note is NOTE_B8 with 7902Hz; if we now * aim for an even even multiple of the buffer-size, we end up with: * ( roundUptoPow2(highest note / AUDIO_DAC_BUFFER_SIZE) * nyquist-rate * AUDIO_DAC_BUFFER_SIZE) * 7902/256 = 30.867 * 2 * 256 ~= 16384 * which works out (but the 'scope shows some sampling artifacts with lower harmonics :-P) */ # define AUDIO_DAC_SAMPLE_RATE 16384U # define AUDIO_MAX_SIMULTANEOUS_TONES 8 #endif /** * Effective bit-rate of the DAC. 44.1khz is the standard for most audio - any * lower will sacrifice perceptible audio quality. Any higher will limit the * number of simultaneous tones. In most situations, a tenth (1/10) of the * sample rate is where notes become unbearable. */ #ifndef AUDIO_DAC_SAMPLE_RATE # define AUDIO_DAC_SAMPLE_RATE 44100U #endif /** * The number of tones that can be played simultaneously. If too high a value * is used here, the keyboard will freeze and glitch-out when that many tones * are being played. */ #ifndef AUDIO_MAX_SIMULTANEOUS_TONES # define AUDIO_MAX_SIMULTANEOUS_TONES 2 #endif /** * The default value of the DAC when not playing anything. Certain hardware * setups may require a high (AUDIO_DAC_SAMPLE_MAX) or low (0) value here. * Since multiple added sine waves tend to oscillate around the midpoint, * and possibly never/rarely reach either 0 of MAX, 1/2 MAX can be a * reasonable default value. */ #ifndef AUDIO_DAC_OFF_VALUE # define AUDIO_DAC_OFF_VALUE AUDIO_DAC_SAMPLE_MAX / 2 #endif #if AUDIO_DAC_OFF_VALUE > AUDIO_DAC_SAMPLE_MAX # error "AUDIO_DAC: OFF_VALUE may not be larger than SAMPLE_MAX" #endif /** *user overridable sample generation/processing */ uint16_t dac_value_generate(void);