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always return audio pin to 0 on ARM

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This commit is contained in:
David Hoelscher 2024-10-18 21:35:13 -05:00
parent 22e6a8d15e
commit fb8351b325
1 changed files with 40 additions and 2 deletions
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42
platforms/chibios/drivers/audio_pwm_hardware.c
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@ -31,6 +31,20 @@
extern bool playing_note;
extern bool playing_melody;
extern uint8_t note_timbre;
static bool channel_1_stopped = true;
void channel_1_stop(void);
void channel_1_start(void);
void audio_wait_for_pin(pin_t pin, uint8_t target_state) {
rtcnt_t start = chSysGetRealtimeCounterX();
rtcnt_t end = start + 5000;
while (chSysIsCounterWithinX(chSysGetRealtimeCounterX(), start, end)) {
if (gpio_read_pin(pin) == target_state) {
break;
}
}
}
static PWMConfig pwmCFG = {.frequency = AUDIO_PWM_COUNTER_FREQUENCY, /* PWM clock frequency */
.period = 2,
@ -44,8 +58,12 @@ void channel_1_set_frequency(float freq) {
if (freq <= 0.0) {
// a pause/rest has freq=0
channel_1_stop();
return;
}
if (channel_1_stopped) {
channel_1_start();
}
pwmcnt_t period = (pwmCFG.frequency / freq);
chSysLockFromISR();
@ -63,12 +81,32 @@ float channel_1_get_frequency(void) {
void channel_1_start(void) {
pwmStop(&AUDIO_PWM_DRIVER);
pwmStart(&AUDIO_PWM_DRIVER, &pwmCFG);
channel_1_stopped = false;
}
void channel_1_stop(void) {
pwmStop(&AUDIO_PWM_DRIVER);
}
// only certain timers will disable the output (set to zero) when the pwm is stopped.
// to ensure the pin is low (without having changing the pin modes), set the
// frequency to the highest valid value and wait for the pin to be zero
chSysLockFromISR();
pwmChangePeriodI(&AUDIO_PWM_DRIVER, 2);
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, 5000));
chSysUnlockFromISR();
// try stopping now if the pin is currently low
audio_wait_for_pin(AUDIO_PIN,0);
pwmStop(&AUDIO_PWM_DRIVER);
// if it isn't actively low, it was stopped a little too late, so keep trying (should only need one more attempt)
while (gpio_read_pin(AUDIO_PIN) == 1) {
pwmStart(&AUDIO_PWM_DRIVER, &pwmCFG);
audio_wait_for_pin(AUDIO_PIN,0);
pwmStop(&AUDIO_PWM_DRIVER);
}
channel_1_stopped = true;
}
static virtual_timer_t audio_vt;
static void audio_callback(virtual_timer_t *vtp, void *p);