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qmk-firmware/platforms/avr/drivers/audio_pwm_hardware.c

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/* Copyright 2016 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/>.
*/
#if defined(__AVR__)
# include <avr/pgmspace.h>
# include <avr/interrupt.h>
# include <avr/io.h>
#endif
#include "audio.h"
extern bool playing_note;
extern bool playing_melody;
extern uint8_t note_timbre;
#define CPU_PRESCALER 8
/*
Audio Driver: PWM
drive up to two speakers through the AVR PWM hardware-peripheral, using timer1 and/or timer3 on Atmega32U4.
the primary channel_1 can be connected to either pin PC4 PC5 or PC6 (the later being used by most AVR based keyboards) with a PMW signal generated by timer3
and an optional secondary channel_2 on either pin PB5, PB6 or PB7, with a PWM signal from timer1
alternatively, the PWM pins on PORTB can be used as only/primary speaker
*/
#if defined(AUDIO_PIN) && (AUDIO_PIN != C4) && (AUDIO_PIN != C5) && (AUDIO_PIN != C6) && (AUDIO_PIN != B5) && (AUDIO_PIN != B6) && (AUDIO_PIN != B7) && (AUDIO_PIN != D5)
# error "Audio feature enabled, but no suitable pin selected as AUDIO_PIN - see docs/feature_audio under the AVR settings for available options."
#endif
#if (AUDIO_PIN == C4) || (AUDIO_PIN == C5) || (AUDIO_PIN == C6)
# define AUDIO1_PIN_SET
# define AUDIO1_TIMSKx TIMSK3
# define AUDIO1_TCCRxA TCCR3A
# define AUDIO1_TCCRxB TCCR3B
# define AUDIO1_ICRx ICR3
# define AUDIO1_WGMx0 WGM30
# define AUDIO1_WGMx1 WGM31
# define AUDIO1_WGMx2 WGM32
# define AUDIO1_WGMx3 WGM33
# define AUDIO1_CSx0 CS30
# define AUDIO1_CSx1 CS31
# define AUDIO1_CSx2 CS32
# if (AUDIO_PIN == C6)
# define AUDIO1_COMxy0 COM3A0
# define AUDIO1_COMxy1 COM3A1
# define AUDIO1_OCIExy OCIE3A
# define AUDIO1_OCRxy OCR3A
# define AUDIO1_PIN C6
# define AUDIO1_TIMERx_COMPy_vect TIMER3_COMPA_vect
# elif (AUDIO_PIN == C5)
# define AUDIO1_COMxy0 COM3B0
# define AUDIO1_COMxy1 COM3B1
# define AUDIO1_OCIExy OCIE3B
# define AUDIO1_OCRxy OCR3B
# define AUDIO1_PIN C5
# define AUDIO1_TIMERx_COMPy_vect TIMER3_COMPB_vect
# elif (AUDIO_PIN == C4)
# define AUDIO1_COMxy0 COM3C0
# define AUDIO1_COMxy1 COM3C1
# define AUDIO1_OCIExy OCIE3C
# define AUDIO1_OCRxy OCR3C
# define AUDIO1_PIN C4
# define AUDIO1_TIMERx_COMPy_vect TIMER3_COMPC_vect
# endif
#endif
#if defined(AUDIO_PIN) && defined(AUDIO_PIN_ALT) && (AUDIO_PIN == AUDIO_PIN_ALT)
# error "Audio feature: AUDIO_PIN and AUDIO_PIN_ALT on the same pin makes no sense."
#endif
#if ((AUDIO_PIN == B5) && ((AUDIO_PIN_ALT == B6) || (AUDIO_PIN_ALT == B7))) || ((AUDIO_PIN == B6) && ((AUDIO_PIN_ALT == B5) || (AUDIO_PIN_ALT == B7))) || ((AUDIO_PIN == B7) && ((AUDIO_PIN_ALT == B5) || (AUDIO_PIN_ALT == B6)))
# error "Audio feature: PORTB as AUDIO_PIN and AUDIO_PIN_ALT at the same time is not supported."
#endif
#if defined(AUDIO_PIN_ALT) && (AUDIO_PIN_ALT != B5) && (AUDIO_PIN_ALT != B6) && (AUDIO_PIN_ALT != B7)
# error "Audio feature: the pin selected as AUDIO_PIN_ALT is not supported."
#endif
#if (AUDIO_PIN == B5) || (AUDIO_PIN == B6) || (AUDIO_PIN == B7) || (AUDIO_PIN_ALT == B5) || (AUDIO_PIN_ALT == B6) || (AUDIO_PIN_ALT == B7) || (AUDIO_PIN == D5)
# define AUDIO2_PIN_SET
# define AUDIO2_TIMSKx TIMSK1
# define AUDIO2_TCCRxA TCCR1A
# define AUDIO2_TCCRxB TCCR1B
# define AUDIO2_ICRx ICR1
# define AUDIO2_WGMx0 WGM10
# define AUDIO2_WGMx1 WGM11
# define AUDIO2_WGMx2 WGM12
# define AUDIO2_WGMx3 WGM13
# define AUDIO2_CSx0 CS10
# define AUDIO2_CSx1 CS11
# define AUDIO2_CSx2 CS12
# if (AUDIO_PIN == B5) || (AUDIO_PIN_ALT == B5)
# define AUDIO2_COMxy0 COM1A0
# define AUDIO2_COMxy1 COM1A1
# define AUDIO2_OCIExy OCIE1A
# define AUDIO2_OCRxy OCR1A
# define AUDIO2_PIN B5
# define AUDIO2_TIMERx_COMPy_vect TIMER1_COMPA_vect
# elif (AUDIO_PIN == B6) || (AUDIO_PIN_ALT == B6)
# define AUDIO2_COMxy0 COM1B0
# define AUDIO2_COMxy1 COM1B1
# define AUDIO2_OCIExy OCIE1B
# define AUDIO2_OCRxy OCR1B
# define AUDIO2_PIN B6
# define AUDIO2_TIMERx_COMPy_vect TIMER1_COMPB_vect
# elif (AUDIO_PIN == B7) || (AUDIO_PIN_ALT == B7)
# define AUDIO2_COMxy0 COM1C0
# define AUDIO2_COMxy1 COM1C1
# define AUDIO2_OCIExy OCIE1C
# define AUDIO2_OCRxy OCR1C
# define AUDIO2_PIN B7
# define AUDIO2_TIMERx_COMPy_vect TIMER1_COMPC_vect
# elif (AUDIO_PIN == D5) && defined(__AVR_ATmega32A__)
# pragma message "Audio support for ATmega32A is experimental and can cause crashes."
# undef AUDIO2_TIMSKx
# define AUDIO2_TIMSKx TIMSK
# define AUDIO2_COMxy0 COM1A0
# define AUDIO2_COMxy1 COM1A1
# define AUDIO2_OCIExy OCIE1A
# define AUDIO2_OCRxy OCR1A
# define AUDIO2_PIN D5
# define AUDIO2_TIMERx_COMPy_vect TIMER1_COMPA_vect
# endif
#endif
// C6 seems to be the assumed default by many existing keyboard - but sill warn the user
#if !defined(AUDIO1_PIN_SET) && !defined(AUDIO2_PIN_SET)
# pragma message "Audio feature enabled, but no suitable pin selected - see docs/feature_audio under the AVR settings for available options. Don't expect to hear anything... :-)"
// TODO: make this an error - go through the breaking-change-process and change all keyboards to the new define
#endif
// -----------------------------------------------------------------------------
#ifdef AUDIO1_PIN_SET
static float channel_1_frequency = 0.0f;
void channel_1_set_frequency(float freq) {
if (freq == 0.0f) // a pause/rest is a valid "note" with freq=0
{
// disable the output, but keep the pwm-ISR going (with the previous
// frequency) so the audio-state keeps getting updated
// Note: setting the duty-cycle 0 is not possible on non-inverting PWM mode - see the AVR data-sheet
AUDIO1_TCCRxA &= ~(_BV(AUDIO1_COMxy1) | _BV(AUDIO1_COMxy0));
return;
} else {
AUDIO1_TCCRxA |= _BV(AUDIO1_COMxy1); // enable output, PWM mode
}
channel_1_frequency = freq;
// set pwm period
AUDIO1_ICRx = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
// and duty cycle
AUDIO1_OCRxy = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre / 100);
}
void channel_1_start(void) {
// enable timer-counter ISR
AUDIO1_TIMSKx |= _BV(AUDIO1_OCIExy);
// enable timer-counter output
AUDIO1_TCCRxA |= _BV(AUDIO1_COMxy1);
}
void channel_1_stop(void) {
// disable timer-counter ISR
AUDIO1_TIMSKx &= ~_BV(AUDIO1_OCIExy);
// disable timer-counter output
AUDIO1_TCCRxA &= ~(_BV(AUDIO1_COMxy1) | _BV(AUDIO1_COMxy0));
}
#endif
#ifdef AUDIO2_PIN_SET
static float channel_2_frequency = 0.0f;
void channel_2_set_frequency(float freq) {
if (freq == 0.0f) {
AUDIO2_TCCRxA &= ~(_BV(AUDIO2_COMxy1) | _BV(AUDIO2_COMxy0));
return;
} else {
AUDIO2_TCCRxA |= _BV(AUDIO2_COMxy1);
}
channel_2_frequency = freq;
AUDIO2_ICRx = (uint16_t)(((float)F_CPU) / (freq * CPU_PRESCALER));
AUDIO2_OCRxy = (uint16_t)((((float)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre / 100);
}
float channel_2_get_frequency(void) {
return channel_2_frequency;
}
void channel_2_start(void) {
AUDIO2_TIMSKx |= _BV(AUDIO2_OCIExy);
AUDIO2_TCCRxA |= _BV(AUDIO2_COMxy1);
}
void channel_2_stop(void) {
AUDIO2_TIMSKx &= ~_BV(AUDIO2_OCIExy);
AUDIO2_TCCRxA &= ~(_BV(AUDIO2_COMxy1) | _BV(AUDIO2_COMxy0));
}
#endif
void audio_driver_initialize() {
#ifdef AUDIO1_PIN_SET
channel_1_stop();
setPinOutput(AUDIO1_PIN);
#endif
#ifdef AUDIO2_PIN_SET
channel_2_stop();
setPinOutput(AUDIO2_PIN);
#endif
// TCCR3A / TCCR3B: Timer/Counter #3 Control Registers TCCR3A/TCCR3B, TCCR1A/TCCR1B
// Compare Output Mode (COM3An and COM1An) = 0b00 = Normal port operation
// OC3A -- PC6
// OC3B -- PC5
// OC3C -- PC4
// OC1A -- PB5
// OC1B -- PB6
// OC1C -- PB7
// Waveform Generation Mode (WGM3n) = 0b1110 = Fast PWM Mode 14. Period = ICR3, Duty Cycle OCR3A)
// OCR3A - PC6
// OCR3B - PC5
// OCR3C - PC4
// OCR1A - PB5
// OCR1B - PB6
// OCR1C - PB7
// Clock Select (CS3n) = 0b010 = Clock / 8
#ifdef AUDIO1_PIN_SET
// initialize timer-counter
AUDIO1_TCCRxA = (0 << AUDIO1_COMxy1) | (0 << AUDIO1_COMxy0) | (1 << AUDIO1_WGMx1) | (0 << AUDIO1_WGMx0);
AUDIO1_TCCRxB = (1 << AUDIO1_WGMx3) | (1 << AUDIO1_WGMx2) | (0 << AUDIO1_CSx2) | (1 << AUDIO1_CSx1) | (0 << AUDIO1_CSx0);
#endif
#ifdef AUDIO2_PIN_SET
AUDIO2_TCCRxA = (0 << AUDIO2_COMxy1) | (0 << AUDIO2_COMxy0) | (1 << AUDIO2_WGMx1) | (0 << AUDIO2_WGMx0);
AUDIO2_TCCRxB = (1 << AUDIO2_WGMx3) | (1 << AUDIO2_WGMx2) | (0 << AUDIO2_CSx2) | (1 << AUDIO2_CSx1) | (0 << AUDIO2_CSx0);
#endif
}
void audio_driver_stop() {
#ifdef AUDIO1_PIN_SET
channel_1_stop();
#endif
#ifdef AUDIO2_PIN_SET
channel_2_stop();
#endif
}
void audio_driver_start(void) {
#ifdef AUDIO1_PIN_SET
channel_1_start();
if (playing_note) {
channel_1_set_frequency(audio_get_processed_frequency(0));
}
#endif
#if !defined(AUDIO1_PIN_SET) && defined(AUDIO2_PIN_SET)
channel_2_start();
if (playing_note) {
channel_2_set_frequency(audio_get_processed_frequency(0));
}
#endif
}
static volatile uint32_t isr_counter = 0;
#ifdef AUDIO1_PIN_SET
ISR(AUDIO1_TIMERx_COMPy_vect) {
isr_counter++;
if (isr_counter < channel_1_frequency / (CPU_PRESCALER * 8)) return;
isr_counter = 0;
bool state_changed = audio_update_state();
if (!playing_note && !playing_melody) {
channel_1_stop();
# ifdef AUDIO2_PIN_SET
channel_2_stop();
# endif
return;
}
if (state_changed) {
channel_1_set_frequency(audio_get_processed_frequency(0));
# ifdef AUDIO2_PIN_SET
if (audio_get_number_of_active_tones() > 1) {
channel_2_set_frequency(audio_get_processed_frequency(1));
} else {
channel_2_stop();
}
# endif
}
}
#endif
#if !defined(AUDIO1_PIN_SET) && defined(AUDIO2_PIN_SET)
ISR(AUDIO2_TIMERx_COMPy_vect) {
isr_counter++;
if (isr_counter < channel_2_frequency / (CPU_PRESCALER * 8)) return;
isr_counter = 0;
bool state_changed = audio_update_state();
if (!playing_note && !playing_melody) {
channel_2_stop();
return;
}
if (state_changed) {
channel_2_set_frequency(audio_get_processed_frequency(0));
}
}
#endif
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