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qmk_firmware

custom branch of QMK firmware git clone https://anongit.hacktivis.me/git/qmk_firmware.git

audio_pwm_hardware.c (4154B)

    

  1. // Copyright 2022 Stefan Kerkmann
  2. // Copyright 2020 Jack Humbert
  3. // Copyright 2020 JohSchneider
  4. // SPDX-License-Identifier: GPL-2.0-or-later
  6. // Audio Driver: PWM the duty-cycle is always kept at 50%, and the pwm-period is
  7. // adjusted to match the frequency of a note to be played back. This driver uses
  8. // the chibios-PWM system to produce a square-wave on specific output pins that
  9. // are connected to the PWM hardware. The hardware directly toggles the pin via
  10. // its alternate function. see your MCUs data-sheet for which pin can be driven
  11. // by what timer - looking for TIMx_CHy and the corresponding alternate
  12. // function.
  14. #include "audio.h"
  15. #include "gpio.h"
  17. #if !defined(AUDIO_PIN)
  18. #    error "Audio feature enabled, but no pin selected - see docs/feature_audio under the ARM PWM settings"
  19. #endif
  21. #if !defined(AUDIO_PWM_COUNTER_FREQUENCY)
  22. #    define AUDIO_PWM_COUNTER_FREQUENCY 100000
  23. #endif
  25. #ifndef AUDIO_PWM_COMPLEMENTARY_OUTPUT
  26. #    define AUDIO_PWM_OUTPUT_MODE PWM_OUTPUT_ACTIVE_HIGH
  27. #else
  28. #    define AUDIO_PWM_OUTPUT_MODE PWM_COMPLEMENTARY_OUTPUT_ACTIVE_HIGH
  29. #endif
  31. extern bool    playing_note;
  32. extern bool    playing_melody;
  33. extern uint8_t note_timbre;
  35. static PWMConfig pwmCFG = {.frequency = AUDIO_PWM_COUNTER_FREQUENCY, /* PWM clock frequency  */
  36.                            .period    = 2,
  37.                            .callback  = NULL,
  38.                            .channels  = {[(AUDIO_PWM_CHANNEL - 1)] = {.mode = AUDIO_PWM_OUTPUT_MODE, .callback = NULL}}};
  40. static float channel_1_frequency = 0.0f;
  42. void channel_1_set_frequency(float freq) {
  43.     channel_1_frequency = freq;
  44.     pwmcnt_t period;
  45.     pwmcnt_t width;
  47.     if (freq <= 0.0) {
  48.         period = 2;
  49.         width  = 0;
  50.     } else {
  51.         period = (pwmCFG.frequency / freq);
  52.         width  = (pwmcnt_t)(((period) * (pwmcnt_t)((100 - note_timbre) * 100)) / (pwmcnt_t)(10000));
  53.     }
  54.     chSysLockFromISR();
  55.     pwmChangePeriodI(&AUDIO_PWM_DRIVER, period);
  56.     pwmEnableChannelI(&AUDIO_PWM_DRIVER, AUDIO_PWM_CHANNEL - 1, width);
  57.     chSysUnlockFromISR();
  58. }
  60. float channel_1_get_frequency(void) {
  61.     return channel_1_frequency;
  62. }
  64. void channel_1_start(void) {
  65.     pwmStop(&AUDIO_PWM_DRIVER);
  66.     pwmStart(&AUDIO_PWM_DRIVER, &pwmCFG);
  67. }
  69. void channel_1_stop(void) {
  70.     pwmStop(&AUDIO_PWM_DRIVER);
  71.     pwmStart(&AUDIO_PWM_DRIVER, &pwmCFG);
  72.     pwmEnableChannel(&AUDIO_PWM_DRIVER, AUDIO_PWM_CHANNEL - 1, 0);
  73.     pwmStop(&AUDIO_PWM_DRIVER);
  74. }
  76. static virtual_timer_t audio_vt;
  77. static void            audio_callback(virtual_timer_t *vtp, void *p);
  79. // a regular timer task, that checks the note to be currently played and updates
  80. // the pwm to output that frequency.
  81. static void audio_callback(virtual_timer_t *vtp, void *p) {
  82.     float freq; // TODO: freq_alt
  84.     if (audio_update_state()) {
  85.         freq = audio_get_processed_frequency(0); // freq_alt would be index=1
  86.         channel_1_set_frequency(freq);
  87.     }
  89.     chSysLockFromISR();
  90.     chVTSetI(&audio_vt, TIME_MS2I(16), audio_callback, NULL);
  91.     chSysUnlockFromISR();
  92. }
  94. void audio_driver_initialize_impl(void) {
  95.     pwmStart(&AUDIO_PWM_DRIVER, &pwmCFG);
  97.     // connect the AUDIO_PIN to the PWM hardware
  98. #if defined(USE_GPIOV1) // STM32F103C8, RP2040
  99.     palSetLineMode(AUDIO_PIN, AUDIO_PWM_PAL_MODE);
  100. #else // GPIOv2 (or GPIOv3 for f4xx, which is the same/compatible at this command)
  101.     palSetLineMode(AUDIO_PIN, PAL_MODE_ALTERNATE(AUDIO_PWM_PAL_MODE));
  102. #endif
  104.     chVTObjectInit(&audio_vt);
  105. }
  107. void audio_driver_start_impl(void) {
  108.     channel_1_stop();
  109.     channel_1_start();
  111.     if ((playing_note || playing_melody) && !chVTIsArmed(&audio_vt)) {
  112.         // a whole note is one beat, which is - per definition in
  113.         // musical_notes.h - set to 64 the longest note is
  114.         // BREAVE_DOT=128+64=192, the shortest SIXTEENTH=4 the tempo (which
  115.         // might vary!) is in bpm (beats per minute) therefore: if the timer
  116.         // ticks away at 64Hz (~16.6ms) audio_update_state is called just often
  117.         // enough to not miss any notes
  118.         chVTSet(&audio_vt, TIME_MS2I(16), audio_callback, NULL);
  119.     }
  120. }
  122. void audio_driver_stop_impl(void) {
  123.     channel_1_stop();
  124.     chVTReset(&audio_vt);
  125. }