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/* 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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