diff options
Diffstat (limited to 'platforms/chibios/drivers/audio_pwm_hardware.c')
| -rw-r--r-- | platforms/chibios/drivers/audio_pwm_hardware.c | 152 |
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); } |