87 lines
2.7 KiB
Arduino
87 lines
2.7 KiB
Arduino
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// CC-by-www.Electrosmash.com
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// Based on OpenMusicLabs previous works.
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// pedalshield_uno_distortion.ino reads the ADC signal and clip it to a threshold value
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// pressing the pushbutton_1 or 2 turns the distortion harder or softer.
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//defining harware resources.
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#define LED 13
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#define FOOTSWITCH 12
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#define TOGGLE 2
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#define PUSHBUTTON_1 A5
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#define PUSHBUTTON_2 A4
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//defining the output PWM parameters
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#define PWM_FREQ 0x00FF // pwm frequency - 31.3KHz
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#define PWM_MODE 0 // Fast (1) or Phase Correct (0)
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#define PWM_QTY 2 // 2 PWMs in parallel
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//other variables
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int input, distortion_threshold=6000; //initial value adjusted by try and error.
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int counter=0;
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unsigned int ADC_low, ADC_high;
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void setup() {
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//setup IO
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pinMode(FOOTSWITCH, INPUT_PULLUP);
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pinMode(TOGGLE, INPUT_PULLUP);
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pinMode(PUSHBUTTON_1, INPUT_PULLUP);
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pinMode(PUSHBUTTON_2, INPUT_PULLUP);
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pinMode(LED, OUTPUT);
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// setup ADC
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ADMUX = 0x60; // left adjust, adc0, internal vcc
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ADCSRA = 0xe5; // turn on adc, ck/32, auto trigger
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ADCSRB = 0x07; // t1 capture for trigger
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DIDR0 = 0x01; // turn off digital inputs for adc0
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// setup PWM
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TCCR1A = (((PWM_QTY - 1) << 5) | 0x80 | (PWM_MODE << 1)); //
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TCCR1B = ((PWM_MODE << 3) | 0x11); // ck/1
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TIMSK1 = 0x20; // interrupt on capture interrupt
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ICR1H = (PWM_FREQ >> 8);
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ICR1L = (PWM_FREQ & 0xff);
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DDRB |= ((PWM_QTY << 1) | 0x02); // turn on outputs
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sei(); // turn on interrupts - not really necessary with arduino
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}
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void loop()
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{
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//Turn on the LED if the effect is ON.
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if (digitalRead(FOOTSWITCH)) digitalWrite(LED, HIGH);
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else digitalWrite(LED, LOW);
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//nothing here, all happens in the Timer 1 interruption.
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}
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ISR(TIMER1_CAPT_vect)
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{
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// get ADC data
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ADC_low = ADCL; // you need to fetch the low byte first
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ADC_high = ADCH;
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//construct the input sumple summing the ADC low and high byte.
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input = ((ADC_high << 8) | ADC_low) + 0x8000; // make a signed 16b value
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counter++; //to save resources, the pushbuttons are checked every 1000 times.
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if(counter==1000)
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{
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counter=0;
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if (!digitalRead(PUSHBUTTON_2)) {
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if (distortion_threshold<32768)distortion_threshold=distortion_threshold+25; //increase the vol
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digitalWrite(LED, LOW); //blinks the led
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}
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if (!digitalRead(PUSHBUTTON_1)) {
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if (distortion_threshold>0)distortion_threshold=distortion_threshold-25; //decrease vol
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digitalWrite(LED, LOW); //blinks the led
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}
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}
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//the input signal is 16bits (values from -32768 to +32768
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//the valueif(input>distortion_threshold) input=distortion_threshold; is clipped to the distortion_threshold value
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if(input>distortion_threshold) input=distortion_threshold;
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//write the PWM signal
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OCR1AL = ((input + 0x8000) >> 8); // convert to unsigned, send out high byte
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OCR1BL = input; // send out low byte
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}
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