diff options
Diffstat (limited to 'quantum')
| -rw-r--r-- | quantum/audio.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/quantum/audio.c b/quantum/audio.c index e4f0bf30e8..1327887d9a 100644 --- a/quantum/audio.c +++ b/quantum/audio.c @@ -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 |