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Diffstat (limited to 'platforms/chibios/drivers/audio_pwm_hardware.c')
-rw-r--r--platforms/chibios/drivers/audio_pwm_hardware.c152
1 files changed, 60 insertions, 92 deletions
diff --git a/platforms/chibios/drivers/audio_pwm_hardware.c b/platforms/chibios/drivers/audio_pwm_hardware.c
index 710f397609..54dac46605 100644
--- a/platforms/chibios/drivers/audio_pwm_hardware.c
+++ b/platforms/chibios/drivers/audio_pwm_hardware.c
@@ -1,29 +1,15 @@
-/* Copyright 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/>.
- */
-
-/*
-Audio Driver: PWM
-
-the duty-cycle is always kept at 50%, and the pwm-period is adjusted to match the frequency of a note to be played back.
-
-this driver uses the chibios-PWM system to produce a square-wave on specific output pins that are connected to the PWM hardware.
-The hardware directly toggles the pin via its alternate function. see your MCUs data-sheet for which pin can be driven by what timer - looking for TIMx_CHy and the corresponding alternate function.
-
- */
+// Copyright 2022 Stefan Kerkmann
+// Copyright 2020 Jack Humbert
+// Copyright 2020 JohSchneider
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// Audio Driver: PWM the duty-cycle is always kept at 50%, and the pwm-period is
+// adjusted to match the frequency of a note to be played back. This driver uses
+// the chibios-PWM system to produce a square-wave on specific output pins that
+// are connected to the PWM hardware. The hardware directly toggles the pin via
+// its alternate function. see your MCUs data-sheet for which pin can be driven
+// by what timer - looking for TIMx_CHy and the corresponding alternate
+// function.
#include "audio.h"
#include "ch.h"
@@ -33,53 +19,36 @@ The hardware directly toggles the pin via its alternate function. see your MCUs
# error "Audio feature enabled, but no pin selected - see docs/feature_audio under the ARM PWM settings"
#endif
+#if !defined(AUDIO_PWM_COUNTER_FREQUENCY)
+# define AUDIO_PWM_COUNTER_FREQUENCY 100000
+#endif
+
extern bool playing_note;
extern bool playing_melody;
extern uint8_t note_timbre;
-static PWMConfig pwmCFG = {
- .frequency = 100000, /* PWM clock frequency */
- // CHIBIOS-BUG? can't set the initial period to <2, or the pwm (hard or software) takes ~130ms with .frequency=500000 for a pwmChangePeriod to take effect; with no output=silence in the meantime
- .period = 2, /* initial PWM period (in ticks) 1S (1/10kHz=0.1mS 0.1ms*10000 ticks=1S) */
- .callback = NULL, /* no callback, the hardware directly toggles the pin */
- .channels =
- {
-#if AUDIO_PWM_CHANNEL == 4
- {PWM_OUTPUT_DISABLED, NULL}, /* channel 0 -> TIMx_CH1 */
- {PWM_OUTPUT_DISABLED, NULL}, /* channel 1 -> TIMx_CH2 */
- {PWM_OUTPUT_DISABLED, NULL}, /* channel 2 -> TIMx_CH3 */
- {PWM_OUTPUT_ACTIVE_HIGH, NULL} /* channel 3 -> TIMx_CH4 */
-#elif AUDIO_PWM_CHANNEL == 3
- {PWM_OUTPUT_DISABLED, NULL},
- {PWM_OUTPUT_DISABLED, NULL},
- {PWM_OUTPUT_ACTIVE_HIGH, NULL}, /* TIMx_CH3 */
- {PWM_OUTPUT_DISABLED, NULL}
-#elif AUDIO_PWM_CHANNEL == 2
- {PWM_OUTPUT_DISABLED, NULL},
- {PWM_OUTPUT_ACTIVE_HIGH, NULL}, /* TIMx_CH2 */
- {PWM_OUTPUT_DISABLED, NULL},
- {PWM_OUTPUT_DISABLED, NULL}
-#else /*fallback to CH1 */
- {PWM_OUTPUT_ACTIVE_HIGH, NULL}, /* TIMx_CH1 */
- {PWM_OUTPUT_DISABLED, NULL},
- {PWM_OUTPUT_DISABLED, NULL},
- {PWM_OUTPUT_DISABLED, NULL}
-#endif
- },
-};
+static PWMConfig pwmCFG = {.frequency = AUDIO_PWM_COUNTER_FREQUENCY, /* PWM clock frequency */
+ .period = 2,
+ .callback = NULL,
+ .channels = {[(AUDIO_PWM_CHANNEL - 1)] = {.mode = PWM_OUTPUT_ACTIVE_HIGH, .callback = NULL}}};
static float channel_1_frequency = 0.0f;
-void channel_1_set_frequency(float freq) {
+
+void channel_1_set_frequency(float freq) {
channel_1_frequency = freq;
- if (freq <= 0.0) // a pause/rest has freq=0
+ if (freq <= 0.0) {
+ // a pause/rest has freq=0
return;
+ }
pwmcnt_t period = (pwmCFG.frequency / freq);
- pwmChangePeriod(&AUDIO_PWM_DRIVER, period);
- pwmEnableChannel(&AUDIO_PWM_DRIVER, AUDIO_PWM_CHANNEL - 1,
- // adjust the duty-cycle so that the output is for 'note_timbre' duration HIGH
- PWM_PERCENTAGE_TO_WIDTH(&AUDIO_PWM_DRIVER, (100 - note_timbre) * 100));
+ chSysLockFromISR();
+ pwmChangePeriodI(&AUDIO_PWM_DRIVER, period);
+ pwmEnableChannelI(&AUDIO_PWM_DRIVER, AUDIO_PWM_CHANNEL - 1,
+ // adjust the duty-cycle so that the output is for 'note_timbre' duration HIGH
+ PWM_PERCENTAGE_TO_WIDTH(&AUDIO_PWM_DRIVER, (100 - note_timbre) * 100));
+ chSysUnlockFromISR();
}
float channel_1_get_frequency(void) {
@@ -95,54 +64,53 @@ void channel_1_stop(void) {
pwmStop(&AUDIO_PWM_DRIVER);
}
-static void gpt_callback(GPTDriver *gptp);
-GPTConfig gptCFG = {
- /* a whole note is one beat, which is - per definition in musical_notes.h - set to 64
- the longest note is BREAVE_DOT=128+64=192, the shortest SIXTEENTH=4
- the tempo (which might vary!) is in bpm (beats per minute)
- therefore: if the timer ticks away at .frequency = (60*64)Hz,
- and the .interval counts from 64 downwards - audio_update_state is
- called just often enough to not miss any notes
- */
- .frequency = 60 * 64,
- .callback = gpt_callback,
-};
+static virtual_timer_t audio_vt;
+static void audio_callback(virtual_timer_t *vtp, void *p);
+
+// a regular timer task, that checks the note to be currently played and updates
+// the pwm to output that frequency.
+static void audio_callback(virtual_timer_t *vtp, void *p) {
+ float freq; // TODO: freq_alt
+
+ if (audio_update_state()) {
+ freq = audio_get_processed_frequency(0); // freq_alt would be index=1
+ channel_1_set_frequency(freq);
+ }
+
+ chSysLockFromISR();
+ chVTSetI(&audio_vt, TIME_MS2I(16), audio_callback, NULL);
+ chSysUnlockFromISR();
+}
void audio_driver_initialize(void) {
pwmStart(&AUDIO_PWM_DRIVER, &pwmCFG);
// connect the AUDIO_PIN to the PWM hardware
-#if defined(USE_GPIOV1) // STM32F103C8
- palSetLineMode(AUDIO_PIN, PAL_MODE_ALTERNATE_PUSHPULL);
+#if defined(USE_GPIOV1) // STM32F103C8, RP2040
+ palSetLineMode(AUDIO_PIN, AUDIO_PWM_PAL_MODE);
#else // GPIOv2 (or GPIOv3 for f4xx, which is the same/compatible at this command)
palSetLineMode(AUDIO_PIN, PAL_MODE_ALTERNATE(AUDIO_PWM_PAL_MODE));
#endif
- gptStart(&AUDIO_STATE_TIMER, &gptCFG);
+ chVTObjectInit(&audio_vt);
}
void audio_driver_start(void) {
channel_1_stop();
channel_1_start();
- if (playing_note || playing_melody) {
- gptStartContinuous(&AUDIO_STATE_TIMER, 64);
+ if ((playing_note || playing_melody) && !chVTIsArmed(&audio_vt)) {
+ // a whole note is one beat, which is - per definition in
+ // musical_notes.h - set to 64 the longest note is
+ // BREAVE_DOT=128+64=192, the shortest SIXTEENTH=4 the tempo (which
+ // might vary!) is in bpm (beats per minute) therefore: if the timer
+ // ticks away at 64Hz (~16.6ms) audio_update_state is called just often
+ // enough to not miss any notes
+ chVTSet(&audio_vt, TIME_MS2I(16), audio_callback, NULL);
}
}
void audio_driver_stop(void) {
channel_1_stop();
- gptStopTimer(&AUDIO_STATE_TIMER);
-}
-
-/* a regular timer task, that checks the note to be currently played
- * and updates the pwm to output that frequency
- */
-static void gpt_callback(GPTDriver *gptp) {
- float freq; // TODO: freq_alt
-
- if (audio_update_state()) {
- freq = audio_get_processed_frequency(0); // freq_alt would be index=1
- channel_1_set_frequency(freq);
- }
+ chVTReset(&audio_vt);
}