diff options
Diffstat (limited to 'platforms/chibios/drivers/audio_dac_additive.c')
| -rw-r--r-- | platforms/chibios/drivers/audio_dac_additive.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/platforms/chibios/drivers/audio_dac_additive.c b/platforms/chibios/drivers/audio_dac_additive.c index 22e4fa2608..26e044b048 100644 --- a/platforms/chibios/drivers/audio_dac_additive.c +++ b/platforms/chibios/drivers/audio_dac_additive.c @@ -84,7 +84,7 @@ static const dacsample_t dac_buffer_trapezoid[AUDIO_DAC_BUFFER_SIZE] = {0x0, 0 0xfff, 0xfdf, 0xf7f, 0xf1f, 0xebf, 0xe5f, 0xdff, 0xd9f, 0xd3f, 0xcdf, 0xc7f, 0xc1f, 0xbbf, 0xb5f, 0xaff, 0xa9f, 0xa3f, 0x9df, 0x97f, 0x91f, 0x8bf, 0x85f, 0x7ff, 0x79f, 0x73f, 0x6df, 0x67f, 0x61f, 0x5bf, 0x55f, 0x4ff, 0x49f, 0x43f, 0x3df, 0x37f, 0x31f, 0x2bf, 0x25f, 0x1ff, 0x19f, 0x13f, 0xdf, 0x7f, 0x1f, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}; #endif // AUDIO_DAC_SAMPLE_WAVEFORM_TRAPEZOID -static dacsample_t dac_buffer_empty[AUDIO_DAC_BUFFER_SIZE] = {AUDIO_DAC_OFF_VALUE}; +static dacsample_t dac_buffer[AUDIO_DAC_BUFFER_SIZE]; /* keep track of the sample position for for each frequency */ static float dac_if[AUDIO_MAX_SIMULTANEOUS_TONES] = {0.0}; @@ -121,24 +121,27 @@ __attribute__((weak)) uint16_t dac_value_generate(void) { /* doing additive wave synthesis over all currently playing tones = adding up * sine-wave-samples for each frequency, scaled by the number of active tones */ - uint16_t value = 0; - float frequency = 0.0f; + uint_fast16_t value = 0; + float frequency = 0.0f; - for (uint8_t i = 0; i < active_tones_snapshot_length; i++) { + for (size_t i = 0; i < active_tones_snapshot_length; i++) { /* Note: a user implementation does not have to rely on the active_tones_snapshot, but * could directly query the active frequencies through audio_get_processed_frequency */ frequency = active_tones_snapshot[i]; - dac_if[i] = dac_if[i] + ((frequency * AUDIO_DAC_BUFFER_SIZE) / AUDIO_DAC_SAMPLE_RATE) * 2 / 3; + float new_dac_if = dac_if[i]; + new_dac_if += frequency * ((float)AUDIO_DAC_BUFFER_SIZE / AUDIO_DAC_SAMPLE_RATE * 2.0f / 3.0f); /*Note: the 2/3 are necessary to get the correct frequencies on the * DAC output (as measured with an oscilloscope), since the gpt * timer runs with 3*AUDIO_DAC_SAMPLE_RATE; and the DAC callback * is called twice per conversion.*/ - dac_if[i] = fmodf(dac_if[i], AUDIO_DAC_BUFFER_SIZE); + while (new_dac_if >= AUDIO_DAC_BUFFER_SIZE) + new_dac_if -= AUDIO_DAC_BUFFER_SIZE; + dac_if[i] = new_dac_if; // Wavetable generation/lookup - uint16_t dac_i = (uint16_t)dac_if[i]; + size_t dac_i = (size_t)new_dac_if; #if defined(AUDIO_DAC_SAMPLE_WAVEFORM_SINE) value += dac_buffer_sine[dac_i] / active_tones_snapshot_length; @@ -308,10 +311,17 @@ void audio_driver_initialize(void) { DACD1.params->dac->CR &= ~DAC_CR_BOFF1; DACD2.params->dac->CR &= ~DAC_CR_BOFF2; + /* Start the DAC output with all off values. This buffer will then get fed + * with samples from dac_end, which will play notes. + */ + for (size_t i = 0; i < AUDIO_DAC_BUFFER_SIZE; i++) { + dac_buffer[i] = AUDIO_DAC_OFF_VALUE; + } + if (AUDIO_PIN == A4) { - dacStartConversion(&DACD1, &dac_conv_cfg, dac_buffer_empty, AUDIO_DAC_BUFFER_SIZE); + dacStartConversion(&DACD1, &dac_conv_cfg, dac_buffer, AUDIO_DAC_BUFFER_SIZE); } else if (AUDIO_PIN == A5) { - dacStartConversion(&DACD2, &dac_conv_cfg, dac_buffer_empty, AUDIO_DAC_BUFFER_SIZE); + dacStartConversion(&DACD2, &dac_conv_cfg, dac_buffer, AUDIO_DAC_BUFFER_SIZE); } // no inverted/out-of-phase waveform (yet?), only pulling AUDIO_PIN_ALT to AUDIO_DAC_OFF_VALUE |