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noise

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This commit is contained in:
twobit 2012-08-06 04:05:19 +02:00
parent aeeafffc6b
commit aa94ac20e3
1 changed files with 8 additions and 3 deletions
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11
firmware/synth.c
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@ -2,7 +2,7 @@
// sample rate is 8M / (3 * 64) // sample rate is 8M / (3 * 64)
enum { WAVE_PULSE, WAVE_SAW, }; enum { WAVE_PULSE, WAVE_SAW, WAVE_NOISE };
typedef struct { typedef struct {
uint8_t wave; uint8_t wave;
@ -43,14 +43,14 @@ static synth_t synth;
void synth_init(void) void synth_init(void)
{ {
// some test values // some test values
synth.channels[0].wave = WAVE_PULSE; synth.channels[0].wave = WAVE_PULSE + 10;
synth.channels[0].speed = 1153; synth.channels[0].speed = 1153;
synth.channels[0].pulse_sweep = 0; synth.channels[0].pulse_sweep = 0;
synth.channels[0].pulse_width = 1 << 31; synth.channels[0].pulse_width = 1 << 31;
synth.channels[1].wave = WAVE_SAW; synth.channels[1].wave = WAVE_SAW;
synth.channels[1].wave = WAVE_NOISE;
synth.channels[1].speed = 1728; synth.channels[1].speed = 1728;
} }
uint16_t synth_mix(void) uint16_t synth_mix(void)
@ -93,6 +93,11 @@ uint16_t synth_mix(void)
amp = (chan->phase >> 8); amp = (chan->phase >> 8);
break; break;
case WAVE_NOISE: // shitty noise
chan->phase = (chan->phase >> 1) ^ (-(chan->phase & 1) & 0xb400);
amp = (chan->phase >> 8);
break;
default: default:
amp = 0; amp = 0;
break; break;