- /* 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);
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