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start of envelope function

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This commit is contained in:
Jack Humbert 2016-04-20 22:29:01 -04:00
parent 7d1a683607
commit 2e303b40ae
1 changed files with 28 additions and 0 deletions
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28
quantum/audio.c
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@ -81,6 +81,7 @@ bool inited = false;
audio_config_t audio_config;
uint16_t envelope_index = 0;
void audio_toggle(void) {
audio_config.enable ^= 1;
@ -298,6 +299,26 @@ float vibrato(float average_freq) {
#endif
float envelope(float f) {
uint16_t compensated_index = (uint16_t)((float)envelope_index * (880.0 / f));
switch (compensated_index) {
case 0:
note_timbre = TIMBRE_50;
break;
case 20:
note_timbre = TIMBRE_25;
break;
case 32:
note_timbre = TIMBRE_12;
break;
case 40 ... 60:
f = f / 2;
note_timbre = TIMBRE_50;
break;
}
return f;
}
ISR(TIMER3_COMPA_vect) {
if (note) {
#ifdef PWM_AUDIO
@ -387,6 +408,12 @@ ISR(TIMER3_COMPA_vect) {
freq = frequency;
}
}
if (envelope_index < 65535) {
envelope_index++;
}
freq = envelope(freq);
ICR3 = (int)(((double)F_CPU) / (freq * CPU_PRESCALER)); // Set max to the period
OCR3A = (int)((((double)F_CPU) / (freq * CPU_PRESCALER)) * note_timbre); // Set compare to half the period
}
@ -495,6 +522,7 @@ if (audio_config.enable && voices < 8) {
if (notes)
stop_all_notes();
note = true;
envelope_index = 0;
#ifdef PWM_AUDIO
freq = freq / SAMPLE_RATE;
#endif