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 6f2d37908d.
150 lines
5.6 KiB
C
150 lines
5.6 KiB
C
/* 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
|
|
|
|
/**
|
|
* 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
|
|
|
|
/**
|
|
* Size of the dac_buffer array. This controls the length of the runtime buffer
|
|
* which accumulates the data to be sent to the DAC every few milliseconds, and
|
|
* it does not need to correspond to the length of the wavetable for the chosen
|
|
* waveform defined by AUDIO_DAC_SAMPLE_WAVEFORM_* in the additive DAC driver.
|
|
* By default, this is set to be as close to 3.3 ms as possible, giving 300 DAC
|
|
* interrupts per second. Any smaller and the interrupt load gets too heavy and
|
|
* this results in crackling due to buffer underrun in the additive DAC driver;
|
|
* too large and the RAM (additive driver) or flash (basic driver) usage may be
|
|
* too high, causing build failures, and matrix scanning is liable to have long
|
|
* periodic pauses that delay key presses or releases or fully lose short taps.
|
|
* Large buffers also cause notes to take longer to stop after they should from
|
|
* music mode or MIDI input.
|
|
* This should be a power of 2 for maximum compatibility.
|
|
*/
|
|
#ifndef AUDIO_DAC_BUFFER_SIZE
|
|
# if AUDIO_DAC_SAMPLE_RATE < 5100U
|
|
# define AUDIO_DAC_BUFFER_SIZE 16U
|
|
# elif AUDIO_DAC_SAMPLE_RATE < 9900U
|
|
# define AUDIO_DAC_BUFFER_SIZE 32U
|
|
# elif AUDIO_DAC_SAMPLE_RATE < 19500U
|
|
# define AUDIO_DAC_BUFFER_SIZE 64U
|
|
# elif AUDIO_DAC_SAMPLE_RATE < 38700U
|
|
# define AUDIO_DAC_BUFFER_SIZE 128U
|
|
# else
|
|
# define AUDIO_DAC_BUFFER_SIZE 256U
|
|
# endif
|
|
#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);
|