229a1690a7
* dac_additive: Decouple the buffer length from the waveform length * Formatting changes for the previous commit * Reformat waveform tables with rows of 16 entries, ending at column 116 * Revert "Reformat waveform tables with rows of 16 entries, ending at column 116" This reverts commit 6f2d37908d6e73e1505ce61e63190f32f051586f.
151 lines
5.6 KiB
C
151 lines
5.6 KiB
C
/* Copyright 2019 Jack Humbert
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* Copyright 2020 JohSchneider
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#ifndef A4
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# define A4 PAL_LINE(GPIOA, 4)
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#endif
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#ifndef A5
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# define A5 PAL_LINE(GPIOA, 5)
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#endif
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/**
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* Highest value allowed sample value.
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* since the DAC is limited to 12 bit, the absolute max is 0xfff = 4095U;
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* lower values adjust the peak-voltage aka volume down.
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* adjusting this value has only an effect on a sample-buffer whose values are
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* are NOT pregenerated - see square-wave
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*/
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#ifndef AUDIO_DAC_SAMPLE_MAX
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# define AUDIO_DAC_SAMPLE_MAX 4095U
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#endif
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#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)
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# define AUDIO_DAC_QUALITY_SANE_MINIMUM
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#endif
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/**
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* These presets allow you to quickly switch between quality settings for
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* the DAC. The sample rate and maximum number of simultaneous tones roughly
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* has an inverse relationship - slightly higher sample rates may be possible.
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*
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* NOTE: a high sample-rate results in a higher cpu-load, which might lead to
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* (audible) discontinuities and/or starve other processes of cpu-time
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* (like RGB-led back-lighting, ...)
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*/
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#ifdef AUDIO_DAC_QUALITY_VERY_LOW
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# define AUDIO_DAC_SAMPLE_RATE 11025U
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# define AUDIO_MAX_SIMULTANEOUS_TONES 8
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#endif
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#ifdef AUDIO_DAC_QUALITY_LOW
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# define AUDIO_DAC_SAMPLE_RATE 22050U
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# define AUDIO_MAX_SIMULTANEOUS_TONES 4
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#endif
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#ifdef AUDIO_DAC_QUALITY_HIGH
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# define AUDIO_DAC_SAMPLE_RATE 44100U
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# define AUDIO_MAX_SIMULTANEOUS_TONES 2
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#endif
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#ifdef AUDIO_DAC_QUALITY_VERY_HIGH
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# define AUDIO_DAC_SAMPLE_RATE 88200U
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# define AUDIO_MAX_SIMULTANEOUS_TONES 1
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#endif
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#ifdef AUDIO_DAC_QUALITY_SANE_MINIMUM
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/* a sane-minimum config: with a trade-off between cpu-load and tone-range
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*
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* the (currently) highest defined note is NOTE_B8 with 7902Hz; if we now
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* aim for an even even multiple of the buffer-size, we end up with:
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* ( roundUptoPow2(highest note / AUDIO_DAC_BUFFER_SIZE) * nyquist-rate * AUDIO_DAC_BUFFER_SIZE)
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* 7902/256 = 30.867 * 2 * 256 ~= 16384
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* which works out (but the 'scope shows some sampling artifacts with lower harmonics :-P)
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*/
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# define AUDIO_DAC_SAMPLE_RATE 16384U
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# define AUDIO_MAX_SIMULTANEOUS_TONES 8
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#endif
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/**
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* Effective bit-rate of the DAC. 44.1khz is the standard for most audio - any
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* lower will sacrifice perceptible audio quality. Any higher will limit the
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* number of simultaneous tones. In most situations, a tenth (1/10) of the
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* sample rate is where notes become unbearable.
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*/
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#ifndef AUDIO_DAC_SAMPLE_RATE
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# define AUDIO_DAC_SAMPLE_RATE 44100U
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#endif
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/**
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* Size of the dac_buffer array. This controls the length of the runtime buffer
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* which accumulates the data to be sent to the DAC every few milliseconds, and
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* it does not need to correspond to the length of the wavetable for the chosen
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* waveform defined by AUDIO_DAC_SAMPLE_WAVEFORM_* in the additive DAC driver.
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* By default, this is set to be as close to 3.3 ms as possible, giving 300 DAC
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* interrupts per second. Any smaller and the interrupt load gets too heavy and
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* this results in crackling due to buffer underrun in the additive DAC driver;
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* too large and the RAM (additive driver) or flash (basic driver) usage may be
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* too high, causing build failures, and matrix scanning is liable to have long
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* periodic pauses that delay key presses or releases or fully lose short taps.
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* Large buffers also cause notes to take longer to stop after they should from
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* music mode or MIDI input.
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* This should be a power of 2 for maximum compatibility.
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*/
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#ifndef AUDIO_DAC_BUFFER_SIZE
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# if AUDIO_DAC_SAMPLE_RATE < 5100U
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# define AUDIO_DAC_BUFFER_SIZE 16U
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# elif AUDIO_DAC_SAMPLE_RATE < 9900U
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# define AUDIO_DAC_BUFFER_SIZE 32U
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# elif AUDIO_DAC_SAMPLE_RATE < 19500U
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# define AUDIO_DAC_BUFFER_SIZE 64U
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# elif AUDIO_DAC_SAMPLE_RATE < 38700U
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# define AUDIO_DAC_BUFFER_SIZE 128U
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# else
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# define AUDIO_DAC_BUFFER_SIZE 256U
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# endif
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#endif
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/**
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* The number of tones that can be played simultaneously. If too high a value
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* is used here, the keyboard will freeze and glitch-out when that many tones
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* are being played.
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*/
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#ifndef AUDIO_MAX_SIMULTANEOUS_TONES
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# define AUDIO_MAX_SIMULTANEOUS_TONES 2
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#endif
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/**
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* The default value of the DAC when not playing anything. Certain hardware
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* setups may require a high (AUDIO_DAC_SAMPLE_MAX) or low (0) value here.
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* Since multiple added sine waves tend to oscillate around the midpoint,
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* and possibly never/rarely reach either 0 of MAX, 1/2 MAX can be a
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* reasonable default value.
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*/
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#ifndef AUDIO_DAC_OFF_VALUE
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# define AUDIO_DAC_OFF_VALUE AUDIO_DAC_SAMPLE_MAX / 2
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#endif
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#if AUDIO_DAC_OFF_VALUE > AUDIO_DAC_SAMPLE_MAX
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# error "AUDIO_DAC: OFF_VALUE may not be larger than SAMPLE_MAX"
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#endif
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/**
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*user overridable sample generation/processing
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*/
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uint16_t dac_value_generate(void);
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