250 lines
8.9 KiB
C
250 lines
8.9 KiB
C
/* Copyright 2016-2020 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/>.
|
|
*/
|
|
|
|
#include "audio.h"
|
|
#include "ch.h"
|
|
#include "hal.h"
|
|
|
|
/*
|
|
Audio Driver: DAC
|
|
|
|
which utilizes both channels of the DAC unit many STM32 are equipped with to output a modulated square-wave, from precomputed samples stored in a buffer, which is passed to the hardware through DMA
|
|
|
|
this driver can either be used to drive to separate speakers, wired to A4+Gnd and A5+Gnd, which allows two tones to be played simultaneously
|
|
OR
|
|
one speaker wired to A4+A5 with the AUDIO_PIN_ALT_AS_NEGATIVE define set - see docs/feature_audio
|
|
|
|
*/
|
|
|
|
#if !defined(AUDIO_PIN)
|
|
# pragma message "Audio feature enabled, but no suitable pin selected as AUDIO_PIN - see docs/feature_audio under 'ARM (DAC basic)' for available options."
|
|
// TODO: make this an 'error' instead; go through a breaking change, and add AUDIO_PIN A5 to all keyboards currently using AUDIO on STM32 based boards? - for now: set the define here
|
|
# define AUDIO_PIN A5
|
|
#endif
|
|
// check configuration for ONE speaker, connected to both DAC pins
|
|
#if defined(AUDIO_PIN_ALT_AS_NEGATIVE) && !defined(AUDIO_PIN_ALT)
|
|
# error "Audio feature: AUDIO_PIN_ALT_AS_NEGATIVE set, but no pin configured as AUDIO_PIN_ALT"
|
|
#endif
|
|
|
|
#ifndef AUDIO_PIN_ALT
|
|
// no ALT pin defined is valid, but the c-ifs below need some value set
|
|
# define AUDIO_PIN_ALT -1
|
|
#endif
|
|
|
|
#if !defined(AUDIO_STATE_TIMER)
|
|
# define AUDIO_STATE_TIMER GPTD8
|
|
#endif
|
|
|
|
// square-wave
|
|
static const dacsample_t dac_buffer_1[AUDIO_DAC_BUFFER_SIZE] = {
|
|
// First half is max, second half is 0
|
|
[0 ... AUDIO_DAC_BUFFER_SIZE / 2 - 1] = AUDIO_DAC_SAMPLE_MAX,
|
|
[AUDIO_DAC_BUFFER_SIZE / 2 ... AUDIO_DAC_BUFFER_SIZE - 1] = 0,
|
|
};
|
|
|
|
// square-wave
|
|
static const dacsample_t dac_buffer_2[AUDIO_DAC_BUFFER_SIZE] = {
|
|
// opposite of dac_buffer above
|
|
[0 ... AUDIO_DAC_BUFFER_SIZE / 2 - 1] = 0,
|
|
[AUDIO_DAC_BUFFER_SIZE / 2 ... AUDIO_DAC_BUFFER_SIZE - 1] = AUDIO_DAC_SAMPLE_MAX,
|
|
};
|
|
|
|
GPTConfig gpt6cfg1 = {.frequency = AUDIO_DAC_SAMPLE_RATE,
|
|
.callback = NULL,
|
|
.cr2 = TIM_CR2_MMS_1, /* MMS = 010 = TRGO on Update Event. */
|
|
.dier = 0U};
|
|
GPTConfig gpt7cfg1 = {.frequency = AUDIO_DAC_SAMPLE_RATE,
|
|
.callback = NULL,
|
|
.cr2 = TIM_CR2_MMS_1, /* MMS = 010 = TRGO on Update Event. */
|
|
.dier = 0U};
|
|
|
|
static void gpt_audio_state_cb(GPTDriver *gptp);
|
|
GPTConfig gptStateUpdateCfg = {.frequency = 10,
|
|
.callback = gpt_audio_state_cb,
|
|
.cr2 = TIM_CR2_MMS_1, /* MMS = 010 = TRGO on Update Event. */
|
|
.dier = 0U};
|
|
|
|
static const DACConfig dac_conf_ch1 = {.init = AUDIO_DAC_OFF_VALUE, .datamode = DAC_DHRM_12BIT_RIGHT};
|
|
static const DACConfig dac_conf_ch2 = {.init = AUDIO_DAC_OFF_VALUE, .datamode = DAC_DHRM_12BIT_RIGHT};
|
|
|
|
/**
|
|
* @note The DAC_TRG(0) here selects the Timer 6 TRGO event, which is triggered
|
|
* on the rising edge after 3 APB1 clock cycles, causing our gpt6cfg1.frequency
|
|
* to be a third of what we expect.
|
|
*
|
|
* Here are all the values for DAC_TRG (TSEL in the ref manual)
|
|
* TIM15_TRGO 0b011
|
|
* TIM2_TRGO 0b100
|
|
* TIM3_TRGO 0b001
|
|
* TIM6_TRGO 0b000
|
|
* TIM7_TRGO 0b010
|
|
* EXTI9 0b110
|
|
* SWTRIG 0b111
|
|
*/
|
|
static const DACConversionGroup dac_conv_grp_ch1 = {.num_channels = 1U, .trigger = DAC_TRG(0b000)};
|
|
static const DACConversionGroup dac_conv_grp_ch2 = {.num_channels = 1U, .trigger = DAC_TRG(0b010)};
|
|
|
|
void channel_1_start(void) {
|
|
gptStart(&GPTD6, &gpt6cfg1);
|
|
gptStartContinuous(&GPTD6, 2U);
|
|
palSetPadMode(GPIOA, 4, PAL_MODE_INPUT_ANALOG);
|
|
}
|
|
|
|
void channel_1_stop(void) {
|
|
gptStopTimer(&GPTD6);
|
|
palSetPadMode(GPIOA, 4, PAL_MODE_OUTPUT_PUSHPULL);
|
|
palSetPad(GPIOA, 4);
|
|
}
|
|
|
|
static float channel_1_frequency = 0.0f;
|
|
void channel_1_set_frequency(float freq) {
|
|
channel_1_frequency = freq;
|
|
|
|
channel_1_stop();
|
|
if (freq <= 0.0) // a pause/rest has freq=0
|
|
return;
|
|
|
|
gpt6cfg1.frequency = 2 * freq * AUDIO_DAC_BUFFER_SIZE;
|
|
channel_1_start();
|
|
}
|
|
float channel_1_get_frequency(void) {
|
|
return channel_1_frequency;
|
|
}
|
|
|
|
void channel_2_start(void) {
|
|
gptStart(&GPTD7, &gpt7cfg1);
|
|
gptStartContinuous(&GPTD7, 2U);
|
|
palSetPadMode(GPIOA, 5, PAL_MODE_INPUT_ANALOG);
|
|
}
|
|
|
|
void channel_2_stop(void) {
|
|
gptStopTimer(&GPTD7);
|
|
palSetPadMode(GPIOA, 5, PAL_MODE_OUTPUT_PUSHPULL);
|
|
palSetPad(GPIOA, 5);
|
|
}
|
|
|
|
static float channel_2_frequency = 0.0f;
|
|
void channel_2_set_frequency(float freq) {
|
|
channel_2_frequency = freq;
|
|
|
|
channel_2_stop();
|
|
if (freq <= 0.0) // a pause/rest has freq=0
|
|
return;
|
|
|
|
gpt7cfg1.frequency = 2 * freq * AUDIO_DAC_BUFFER_SIZE;
|
|
channel_2_start();
|
|
}
|
|
float channel_2_get_frequency(void) {
|
|
return channel_2_frequency;
|
|
}
|
|
|
|
static void gpt_audio_state_cb(GPTDriver *gptp) {
|
|
if (audio_update_state()) {
|
|
#if defined(AUDIO_PIN_ALT_AS_NEGATIVE)
|
|
// one piezo/speaker connected to both audio pins, the generated square-waves are inverted
|
|
channel_1_set_frequency(audio_get_processed_frequency(0));
|
|
channel_2_set_frequency(audio_get_processed_frequency(0));
|
|
|
|
#else // two separate audio outputs/speakers
|
|
// primary speaker on A4, optional secondary on A5
|
|
if (AUDIO_PIN == A4) {
|
|
channel_1_set_frequency(audio_get_processed_frequency(0));
|
|
if (AUDIO_PIN_ALT == A5) {
|
|
if (audio_get_number_of_active_tones() > 1) {
|
|
channel_2_set_frequency(audio_get_processed_frequency(1));
|
|
} else {
|
|
channel_2_stop();
|
|
}
|
|
}
|
|
}
|
|
|
|
// primary speaker on A5, optional secondary on A4
|
|
if (AUDIO_PIN == A5) {
|
|
channel_2_set_frequency(audio_get_processed_frequency(0));
|
|
if (AUDIO_PIN_ALT == A4) {
|
|
if (audio_get_number_of_active_tones() > 1) {
|
|
channel_1_set_frequency(audio_get_processed_frequency(1));
|
|
} else {
|
|
channel_1_stop();
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
void audio_driver_initialize() {
|
|
if ((AUDIO_PIN == A4) || (AUDIO_PIN_ALT == A4)) {
|
|
palSetPadMode(GPIOA, 4, PAL_MODE_INPUT_ANALOG);
|
|
dacStart(&DACD1, &dac_conf_ch1);
|
|
|
|
// initial setup of the dac-triggering timer is still required, even
|
|
// though it gets reconfigured and restarted later on
|
|
gptStart(&GPTD6, &gpt6cfg1);
|
|
}
|
|
|
|
if ((AUDIO_PIN == A5) || (AUDIO_PIN_ALT == A5)) {
|
|
palSetPadMode(GPIOA, 5, PAL_MODE_INPUT_ANALOG);
|
|
dacStart(&DACD2, &dac_conf_ch2);
|
|
|
|
gptStart(&GPTD7, &gpt7cfg1);
|
|
}
|
|
|
|
/* enable the output buffer, to directly drive external loads with no additional circuitry
|
|
*
|
|
* see: AN4566 Application note: Extending the DAC performance of STM32 microcontrollers
|
|
* Note: Buffer-Off bit -> has to be set 0 to enable the output buffer
|
|
* Note: enabling the output buffer imparts an additional dc-offset of a couple mV
|
|
*
|
|
* this is done here, reaching directly into the stm32 registers since chibios has not implemented BOFF handling yet
|
|
* (see: chibios/os/hal/ports/STM32/todo.txt '- BOFF handling in DACv1.'
|
|
*/
|
|
DACD1.params->dac->CR &= ~DAC_CR_BOFF1;
|
|
DACD2.params->dac->CR &= ~DAC_CR_BOFF2;
|
|
|
|
// start state-updater
|
|
gptStart(&AUDIO_STATE_TIMER, &gptStateUpdateCfg);
|
|
}
|
|
|
|
void audio_driver_stop(void) {
|
|
if ((AUDIO_PIN == A4) || (AUDIO_PIN_ALT == A4)) {
|
|
gptStopTimer(&GPTD6);
|
|
|
|
// stop the ongoing conversion and put the output in a known state
|
|
dacStopConversion(&DACD1);
|
|
dacPutChannelX(&DACD1, 0, AUDIO_DAC_OFF_VALUE);
|
|
}
|
|
|
|
if ((AUDIO_PIN == A5) || (AUDIO_PIN_ALT == A5)) {
|
|
gptStopTimer(&GPTD7);
|
|
|
|
dacStopConversion(&DACD2);
|
|
dacPutChannelX(&DACD2, 0, AUDIO_DAC_OFF_VALUE);
|
|
}
|
|
gptStopTimer(&AUDIO_STATE_TIMER);
|
|
}
|
|
|
|
void audio_driver_start(void) {
|
|
if ((AUDIO_PIN == A4) || (AUDIO_PIN_ALT == A4)) {
|
|
dacStartConversion(&DACD1, &dac_conv_grp_ch1, (dacsample_t *)dac_buffer_1, AUDIO_DAC_BUFFER_SIZE);
|
|
}
|
|
if ((AUDIO_PIN == A5) || (AUDIO_PIN_ALT == A5)) {
|
|
dacStartConversion(&DACD2, &dac_conv_grp_ch2, (dacsample_t *)dac_buffer_2, AUDIO_DAC_BUFFER_SIZE);
|
|
}
|
|
gptStartContinuous(&AUDIO_STATE_TIMER, 2U);
|
|
}
|