Merge branch 'master' of ssh://git.xpub.nl:2501/XPUB/special-issue-x
commit
a330759bc5
@ -0,0 +1,15 @@
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STRINGS1
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======
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* Knob 1: Loop start
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* Knob 2: Loop length
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* Knob 3: Pitch
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* Input 3: Gate trigger
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All code ripped from Framen who ripped and modified these fine people's work:
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* http://www.ginkosynthese.com/product/grains/
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* http://playground.arduino.cc/Code/PCMAudio
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* michael@hurts.ca
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* https://www.facebook.com/HRTLmuzik
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* https://github.com/thatpixguy/hrtl-amen
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@ -0,0 +1,137 @@
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#include <stdint.h>
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#include <avr/interrupt.h>
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#include <avr/io.h>
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#include <avr/pgmspace.h>
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#include "sample.h"
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#define LED_PIN 13
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#define SPEAKER_PIN 11
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#define KNOB_1 (0)
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#define KNOB_2 (1)
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#define KNOB_3 (2)
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#define INPUT_3 (3)
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volatile uint16_t sample;
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volatile uint16_t loop_start;
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volatile uint16_t loop_length;
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volatile uint16_t index_bounds;
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volatile uint16_t loop_overflow;
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volatile boolean gate;
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volatile boolean gate_prev;
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byte lastSample;
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void startPlayback()
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{
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pinMode(SPEAKER_PIN, OUTPUT);
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// Set up Timer 2 to do pulse width modulation on the speaker pin.
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// Use internal clock (datasheet p.160)
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ASSR &= ~(_BV(EXCLK) | _BV(AS2));
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// Set fast PWM mode (p.157)
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TCCR2A |= _BV(WGM21) | _BV(WGM20);
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TCCR2B &= ~_BV(WGM22);
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// Do non-inverting PWM on pin OC2A (p.155)
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// On the Arduino this is pin 11.
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TCCR2A = (TCCR2A | _BV(COM2A1)) & ~_BV(COM2A0);
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TCCR2A &= ~(_BV(COM2B1) | _BV(COM2B0));
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// No prescaler (p.158)
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TCCR2B = (TCCR2B & ~(_BV(CS12) | _BV(CS11))) | _BV(CS10);
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// Set initial pulse width to the first sample.
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OCR2A = pgm_read_byte(&sound_data[0]);
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// Set up Timer 1 to send a sample every interrupt.
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cli();
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// Set CTC mode (Clear Timer on Compare Match) (p.133)
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// Have to set OCR1A *after*, otherwise it gets reset to 0!
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TCCR1B = (TCCR1B & ~_BV(WGM13)) | _BV(WGM12);
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TCCR1A = TCCR1A & ~(_BV(WGM11) | _BV(WGM10));
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// No prescaler (p.134)
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TCCR1B = (TCCR1B & ~(_BV(CS12) | _BV(CS11))) | _BV(CS10);
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// Set the compare register (OCR1A).
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// OCR1A is a 16-bit register, so we have to do this with
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// interrupts disabled to be safe.
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OCR1A = F_CPU / SAMPLE_RATE; // 16e6 / 8000 = 2000
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// Enable interrupt when TCNT1 == OCR1A (p.136)
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TIMSK1 |= _BV(OCIE1A);
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lastSample = pgm_read_byte(&sound_data[sound_length - 1]);
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sample = 0;
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sei();
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}
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void stopPlayback()
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{
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TIMSK1 &= ~_BV(OCIE1A); // Disable playback per-sample interrupt.
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TCCR1B &= ~_BV(CS10); // Disable the per-sample timer completely.
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TCCR2B &= ~_BV(CS10); // Disable the PWM timer.
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digitalWrite(SPEAKER_PIN, LOW);
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}
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void setup()
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{
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pinMode(LED_PIN, OUTPUT);
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digitalWrite(LED_PIN, HIGH);
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startPlayback();
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loop_start = 0;
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loop_length = sound_length;
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gate = false;
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gate_prev = false;
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}
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// This is called at 8000 Hz to load the next sample.
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ISR(TIMER1_COMPA_vect)
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{
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if(sample >= index_bounds)
|
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{
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sample = loop_start;
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}
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else if((sample < loop_start) &&
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(sample >= loop_overflow))
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{
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sample = loop_start;
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}
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else if((gate == true) &&
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(gate_prev == false))
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{
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sample = loop_start;
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}
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else
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{
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OCR2A = pgm_read_byte(&sound_data[sample % sound_length]);
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}
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gate_prev = gate;
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sample++;
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}
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void loop()
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{
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loop_start = analogRead(KNOB_1) / 1024.0 * sound_length;
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loop_length = (analogRead(KNOB_2) + 1) / 1024.0 * sound_length;
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OCR1A = (512.0 / (analogRead(KNOB_3) + 1)) * (F_CPU / SAMPLE_RATE);
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gate = analogRead(3) >> 9; // 10 bits in. gate < 512 == off, gate >= 512 == on
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||||
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// can be up to 2x sound length. the more you know.
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index_bounds = loop_start + loop_length;
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// this will set the overflow length. take the loop overflow into account when checking the loop boundaries
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if(index_bounds > sound_length)
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{
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loop_overflow = index_bounds - sound_length;
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}
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else
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{
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||||
loop_overflow = 0;
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}
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}
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File diff suppressed because it is too large
Load Diff
@ -0,0 +1,265 @@
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/*
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"Tri-Shape", a wave shaping oscilatorfor Ginkosynthese's "grains" module.
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By Kassen Oud
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|
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LICENSE:
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This program is free software: you can redistribute it and/or modify
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||||
it under the terms of the GNU General Public License as published by
|
||||
the Free Software Foundation, either version 2 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
This program is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
GNU General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU General Public License
|
||||
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
DESCRIPION;
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A triangle-based osclitator with wave-folding and hard-clipping features.
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||||
|
||||
MANUAL;
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||||
Knob 1 / mod 1; Wave folding
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Amplifies the base triangle wave, then once it hits the limits of the
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range "folds" it back in the opposite direction. With enough
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amplification this will happen again at the other side, creating a
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rich spectrum.
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Knob 2/ mod 2; Hard Cliping
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Amplifies the signal (after the folding) and clips the result. This is
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done asymetrically for a "deeper" and more "balsy" sound. Thanks to
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Rob Bothof for that trick.
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Knob 3: Base Tuning.
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Sets the base pitch.
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Mod 3; Pitch Modulation
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This CV gets added to the value set by Knob 3.
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||||
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||||
*/
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||||
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//the libraries we use
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#include <avr/io.h>
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||||
#include <avr/interrupt.h>
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#include <avr/pgmspace.h>
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||||
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//variables
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uint16_t phase_accumulator; //keeps track of the phase
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uint16_t phase_inc; //phase increase per sample
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||||
bool flip = false; //keeps track of the output's polarity
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uint16_t wrap = 1; // amount of wave-folding
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uint16_t drive = 32; //amount of clipping for positive signal
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uint16_t top_drive = 32; //same for negative signal
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uint16_t output = 127; //the value we write out
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uint16_t last_out = 127; //last value we wrote out
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// Map inputs
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#define DRIVE_CONTROL (A1)
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#define WRAP_CONTROL (A2)
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#define PITCH_KNOB (A0)
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#define PITCH_CV (A3)
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// Changing these will also requires rewriting setup()
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// Output is on pin 11
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#define PWM_PIN 11
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#define PWM_VALUE OCR2A
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#define LED_PORT PORTB
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#define LED_BIT 5
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#define PWM_INTERRUPT TIMER2_OVF_vect
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//maps cv to samples of phase increase each time we output a new value
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//this might need tuning in the future
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const uint16_t freqTable[] PROGMEM = {
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69, 69, 69, 69, 70, 70, 70, 70, 70, 71, // 0 to 9
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71, 71, 71, 72, 72, 72, 72, 73, 73, 73, //
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73, 74, 74, 74, 74, 75, 75, 75, 75, 76, //
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76, 76, 76, 77, 77, 77, 77, 78, 78, 78, //
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78, 79, 79, 79, 79, 80, 80, 80, 81, 81, //
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81, 81, 82, 82, 82, 82, 83, 83, 83, 84, //
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84, 84, 84, 85, 85, 85, 86, 86, 86, 86, //
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87, 87, 87, 88, 88, 88, 88, 89, 89, 89, //
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90, 90, 90, 91, 91, 91, 91, 92, 92, 92, //
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93, 93, 93, 94, 94, 94, 95, 95, 95, 96, //
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96, 96, 97, 97, 97, 97, 98, 98, 98, 99, // 100 to 109
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99, 99, 100, 100, 100, 101, 101, 101, 102, 102, //
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102, 103, 103, 104, 104, 104, 105, 105, 105, 106, //
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106, 106, 107, 107, 107, 108, 108, 109, 109, 109, //
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110, 110, 110, 111, 111, 111, 112, 112, 113, 113, //
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113, 114, 114, 114, 115, 115, 116, 116, 116, 117, //
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117, 118, 118, 118, 119, 119, 120, 120, 120, 121, //
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121, 122, 122, 122, 123, 123, 124, 124, 124, 125, //
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125, 126, 126, 127, 127, 127, 128, 128, 129, 129, //
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130, 130, 130, 131, 131, 132, 132, 133, 133, 134, //
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134, 134, 135, 135, 136, 136, 137, 137, 138, 138, // 200 to 209
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139, 139, 139, 140, 140, 141, 141, 142, 142, 143, //
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143, 144, 144, 145, 145, 146, 146, 147, 147, 148, //
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148, 149, 149, 150, 150, 151, 151, 152, 152, 153, //
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153, 154, 154, 155, 155, 156, 156, 157, 157, 158, //
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158, 159, 159, 160, 161, 161, 162, 162, 163, 163, //
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164, 164, 165, 165, 166, 167, 167, 168, 168, 169, //
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169, 170, 171, 171, 172, 172, 173, 173, 174, 175, //
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175, 176, 176, 177, 178, 178, 179, 179, 180, 181, //
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181, 182, 182, 183, 184, 184, 185, 185, 186, 187, //
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187, 188, 189, 189, 190, 190, 191, 192, 192, 193, // 300 to 309
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194, 194, 195, 196, 196, 197, 198, 198, 199, 200, //
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200, 201, 202, 202, 203, 204, 204, 205, 206, 206, //
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||||
207, 208, 208, 209, 210, 211, 211, 212, 213, 213, //
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||||
214, 215, 216, 216, 217, 218, 218, 219, 220, 221, //
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||||
221, 222, 223, 224, 224, 225, 226, 227, 227, 228, //
|
||||
229, 230, 231, 231, 232, 233, 234, 234, 235, 236, //
|
||||
237, 238, 238, 239, 240, 241, 242, 242, 243, 244, //
|
||||
245, 246, 246, 247, 248, 249, 250, 251, 251, 252, //
|
||||
253, 254, 255, 256, 257, 257, 258, 259, 260, 261, //
|
||||
262, 263, 264, 264, 265, 266, 267, 268, 269, 270, // 400 to 409
|
||||
271, 272, 273, 273, 274, 275, 276, 277, 278, 279, //
|
||||
280, 281, 282, 283, 284, 285, 286, 287, 288, 288, //
|
||||
289, 290, 291, 292, 293, 294, 295, 296, 297, 298, //
|
||||
299, 300, 301, 302, 303, 304, 305, 306, 307, 308, //
|
||||
310, 311, 312, 313, 314, 315, 316, 317, 318, 319, //
|
||||
320, 321, 322, 323, 324, 325, 327, 328, 329, 330, //
|
||||
331, 332, 333, 334, 335, 337, 338, 339, 340, 341, //
|
||||
342, 343, 345, 346, 347, 348, 349, 350, 352, 353, //
|
||||
354, 355, 356, 357, 359, 360, 361, 362, 363, 365, //
|
||||
366, 367, 368, 370, 371, 372, 373, 375, 376, 377, // 500 to 509
|
||||
378, 380, 381, 382, 383, 385, 386, 387, 389, 390, //
|
||||
391, 393, 394, 395, 397, 398, 399, 401, 402, 403, //
|
||||
405, 406, 407, 409, 410, 411, 413, 414, 416, 417, //
|
||||
418, 420, 421, 423, 424, 425, 427, 428, 430, 431, //
|
||||
433, 434, 436, 437, 438, 440, 441, 443, 444, 446, //
|
||||
447, 449, 450, 452, 453, 455, 456, 458, 460, 461, //
|
||||
463, 464, 466, 467, 469, 470, 472, 474, 475, 477, //
|
||||
478, 480, 482, 483, 485, 486, 488, 490, 491, 493, //
|
||||
495, 496, 498, 500, 501, 503, 505, 506, 508, 510, //
|
||||
511, 513, 515, 517, 518, 520, 522, 524, 525, 527, // 600 to 609
|
||||
529, 531, 532, 534, 536, 538, 540, 541, 543, 545, //
|
||||
547, 549, 551, 552, 554, 556, 558, 560, 562, 564, //
|
||||
566, 567, 569, 571, 573, 575, 577, 579, 581, 583, //
|
||||
585, 587, 589, 591, 593, 595, 597, 599, 601, 603, //
|
||||
605, 607, 609, 611, 613, 615, 617, 619, 621, 623, //
|
||||
625, 627, 630, 632, 634, 636, 638, 640, 642, 644, //
|
||||
647, 649, 651, 653, 655, 658, 660, 662, 664, 666, //
|
||||
669, 671, 673, 675, 678, 680, 682, 685, 687, 689, //
|
||||
691, 694, 696, 698, 701, 703, 705, 708, 710, 713, //
|
||||
715, 717, 720, 722, 725, 727, 729, 732, 734, 737, // 700 to 709
|
||||
739, 742, 744, 747, 749, 752, 754, 757, 759, 762, //
|
||||
764, 767, 770, 772, 775, 777, 780, 783, 785, 788, //
|
||||
791, 793, 796, 799, 801, 804, 807, 809, 812, 815, //
|
||||
817, 820, 823, 826, 828, 831, 834, 837, 840, 842, //
|
||||
845, 848, 851, 854, 857, 860, 862, 865, 868, 871, //
|
||||
874, 877, 880, 883, 886, 889, 892, 895, 898, 901, //
|
||||
904, 907, 910, 913, 916, 919, 922, 925, 928, 932, //
|
||||
935, 938, 941, 944, 947, 950, 954, 957, 960, 963, //
|
||||
966, 970, 973, 976, 979, 983, 986, 989, 993, 996, //
|
||||
999,1003,1006,1009,1013,1016,1020,1023,1027,1030, // 800 to 809
|
||||
1033,1037,1040,1044,1047,1051,1054,1058,1061,1065, //
|
||||
1069,1072,1076,1079,1083,1087,1090,1094,1098,1101, //
|
||||
1105,1109,1112,1116,1120,1124,1127,1131,1135,1139, //
|
||||
1143,1146,1150,1154,1158,1162,1166,1170,1174,1178, //
|
||||
1182,1186,1189,1193,1197,1201,1206,1210,1214,1218, //
|
||||
1222,1226,1230,1234,1238,1242,1247,1251,1255,1259, //
|
||||
1263,1268,1272,1276,1280,1285,1289,1293,1298,1302, //
|
||||
1306,1311,1315,1320,1324,1328,1333,1337,1342,1346, //
|
||||
1351,1355,1360,1365,1369,1374,1378,1383,1388,1392, //
|
||||
1397,1402,1406,1411,1416,1421,1425,1430,1435,1440, // 900 to 909
|
||||
1444,1449,1454,1459,1464,1469,1474,1479,1484,1489, //
|
||||
1494,1499,1504,1509,1514,1519,1524,1529,1534,1539, //
|
||||
1545,1550,1555,1560,1565,1571,1576,1581,1587,1592, //
|
||||
1597,1603,1608,1613,1619,1624,1630,1635,1641,1646, //
|
||||
1652,1657,1663,1668,1674,1679,1685,1691,1696,1702, //
|
||||
1708,1714,1719,1725,1731,1737,1742,1748,1754,1760, //
|
||||
1766,1772,1778,1784,1790,1796,1802,1808,1814,1820, //
|
||||
1826,1832,1838,1845,1851,1857,1863,1869,1876,1882, //
|
||||
1888,1895,1901,1907,1914,1920,1927,1933,1940,1946, //
|
||||
1953,1959,1966,1972,1979,1986,1992,1999,2006,2012, // 1000 to 1009
|
||||
2019,2026,2033,2040,2046,2053,2060,2067,2074,2081, // 1010 to 1019
|
||||
2088,2095,2102,2109 , // 1020 to 1023
|
||||
};
|
||||
|
||||
uint16_t mapFreq(uint16_t input)
|
||||
{
|
||||
return pgm_read_word_near(freqTable + input);
|
||||
}
|
||||
|
||||
//sets up pins and configures the samplerate and frequency of the PWM output
|
||||
void setup()
|
||||
{
|
||||
TCCR2A = _BV(COM2A1) | _BV(WGM20);
|
||||
TCCR2B = _BV(CS20);
|
||||
TIMSK2 = _BV(TOIE2);
|
||||
pinMode(PWM_PIN,OUTPUT);
|
||||
PWM_VALUE = 127;
|
||||
}
|
||||
|
||||
//reads modulation inputs
|
||||
void loop()
|
||||
{
|
||||
//calculate the pitch
|
||||
int pwmv = min( 1023, analogRead(PITCH_CV) + analogRead(PITCH_KNOB));
|
||||
//look up the phase increase per sample
|
||||
phase_inc = mapFreq(pwmv);
|
||||
//read the control for wave-folding
|
||||
wrap = min( 64 + (analogRead(WRAP_CONTROL) >> 1), 511);
|
||||
//read the control for clipping and calculate the two amounts of overdrive
|
||||
drive = min( 32 + (analogRead(DRIVE_CONTROL) >> 1), 511);
|
||||
top_drive = max( 32, drive >>1);
|
||||
}
|
||||
|
||||
//Actual sound generation happens here.
|
||||
//This involves rather a lot of bitwise operations, if you're looking to get
|
||||
//into writing code for the Grains I'd suggest not starting here; "PWM-Saw" is
|
||||
//far more "friendly". That's a nice way of saying "Here be Dragons".
|
||||
//I'm writing numbers out as literal trains of 0's and 1's because we make fair
|
||||
//ampount of use of those. Also note that a lot of the structure for this is
|
||||
//caused by avoiding signed integers, while we do want a symetrical signal.
|
||||
//Hence; we treat it as a unipolar signal, keep track of the polarity it should
|
||||
//be and apply that at the end.
|
||||
//I drew the process out on graph paper using multicoloured fineliner.
|
||||
//If you're serious about following all of this that might help.
|
||||
SIGNAL(PWM_INTERRUPT)
|
||||
{
|
||||
//increase the phase
|
||||
phase_accumulator += phase_inc;
|
||||
//2nd half of the phase will be the negative part of the cycle
|
||||
flip = phase_accumulator & 0b1000000000000000;
|
||||
//turn the phase acumulator into 4 up-ramps
|
||||
output = (phase_accumulator & 0b0011111111111111);
|
||||
//get these into 7 bit range. "flip" will be the 8th bit of the output
|
||||
output = output >> 7;
|
||||
//invert the 2nd and 4th of our 4 up-ramps to create our triangle wave
|
||||
if (phase_accumulator & 0b0100000000000000) output = (uint16_t)127 - output;
|
||||
|
||||
//amplify the signal for the wave-wrapping
|
||||
output *= wrap;
|
||||
output = output >> 6;
|
||||
//detect whether folding will be more involved than inverting the range
|
||||
//from 128 to 254
|
||||
if (output & 0b1111111100000000)
|
||||
{
|
||||
//values between 255 and 511 fold back past the "0" line
|
||||
if (output & 0b0000000100000000) flip = !flip;
|
||||
//mask out bits beyond which the process just repeats
|
||||
output &= 0b0000000011111111;
|
||||
}
|
||||
//actual folding
|
||||
if (output > (uint16_t)127)
|
||||
{
|
||||
output = 127 - (output & 0b0000000001111111);
|
||||
}
|
||||
|
||||
//apply the signal gain for asymetrical clipping
|
||||
output *= flip?drive:top_drive;
|
||||
output = output >> 5;
|
||||
//clip
|
||||
if (output > (uint16_t)127) output = (uint16_t)127;
|
||||
|
||||
//turn our 7bit unipolar value into a 8bit bipolar one
|
||||
if ( flip ) output = (uint16_t)127 - output;
|
||||
else output += (uint16_t)127;
|
||||
|
||||
//slight amount of smoothing
|
||||
output = (output + last_out) >> 1;
|
||||
last_out = output;
|
||||
|
||||
//write out the output
|
||||
PWM_VALUE = output;
|
||||
}
|
||||
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Reference in New Issue