diff options
Diffstat (limited to 'platforms/chibios/drivers/audio_dac.h')
| -rw-r--r-- | platforms/chibios/drivers/audio_dac.h | 34 |
1 files changed, 29 insertions, 5 deletions
diff --git a/platforms/chibios/drivers/audio_dac.h b/platforms/chibios/drivers/audio_dac.h index 07cd622ead..2f62d12934 100644 --- a/platforms/chibios/drivers/audio_dac.h +++ b/platforms/chibios/drivers/audio_dac.h @@ -24,11 +24,6 @@ #endif /** - * Size of the dac_buffer arrays. All must be the same size. - */ -#define AUDIO_DAC_BUFFER_SIZE 256U - -/** * Highest value allowed sample value. * since the DAC is limited to 12 bit, the absolute max is 0xfff = 4095U; @@ -97,6 +92,35 @@ #endif /** + * Size of the dac_buffer array. This controls the length of the runtime buffer + * which accumulates the data to be sent to the DAC every few milliseconds, and + * it does not need to correspond to the length of the wavetable for the chosen + * waveform defined by AUDIO_DAC_SAMPLE_WAVEFORM_* in the additive DAC driver. + * By default, this is set to be as close to 3.3 ms as possible, giving 300 DAC + * interrupts per second. Any smaller and the interrupt load gets too heavy and + * this results in crackling due to buffer underrun in the additive DAC driver; + * too large and the RAM (additive driver) or flash (basic driver) usage may be + * too high, causing build failures, and matrix scanning is liable to have long + * periodic pauses that delay key presses or releases or fully lose short taps. + * Large buffers also cause notes to take longer to stop after they should from + * music mode or MIDI input. + * This should be a power of 2 for maximum compatibility. + */ +#ifndef AUDIO_DAC_BUFFER_SIZE +# if AUDIO_DAC_SAMPLE_RATE < 5100U +# define AUDIO_DAC_BUFFER_SIZE 16U +# elif AUDIO_DAC_SAMPLE_RATE < 9900U +# define AUDIO_DAC_BUFFER_SIZE 32U +# elif AUDIO_DAC_SAMPLE_RATE < 19500U +# define AUDIO_DAC_BUFFER_SIZE 64U +# elif AUDIO_DAC_SAMPLE_RATE < 38700U +# define AUDIO_DAC_BUFFER_SIZE 128U +# else +# define AUDIO_DAC_BUFFER_SIZE 256U +# endif +#endif + +/** * The number of tones that can be played simultaneously. If too high a value * is used here, the keyboard will freeze and glitch-out when that many tones * are being played. |