88 lines
2.6 KiB
Arduino
88 lines
2.6 KiB
Arduino
|
// CC-by-www.Electrosmash.com
|
||
|
|
// Based on OpenMusicLabs previous works.
|
||
|
|
/* pedalshield_uno_bit_crusher.ino reads the ADC and shift the bits creating a high distorted sound
|
||
|
|
* pressing the pushbutton_1 or 2 turns the bit shift harder or softer..
|
||
|
|
*/
|
||
|
|
|
||
|
|
//defining harware resources.
|
||
|
|
#define LED 13
|
||
|
|
#define FOOTSWITCH 12
|
||
|
|
#define TOGGLE 2
|
||
|
|
#define PUSHBUTTON_1 A5
|
||
|
|
#define PUSHBUTTON_2 A4
|
||
|
|
|
||
|
|
//defining the output PWM parameters
|
||
|
|
#define PWM_FREQ 0x00FF // pwm frequency - 31.3KHz
|
||
|
|
#define PWM_MODE 0 // Fast (1) or Phase Correct (0)
|
||
|
|
#define PWM_QTY 2 // 2 PWMs in parallel
|
||
|
|
|
||
|
|
//other variables
|
||
|
|
int input, bit_crush_variable=0;
|
||
|
|
int counter=0;
|
||
|
|
unsigned int ADC_low, ADC_high;
|
||
|
|
|
||
|
|
void setup() {
|
||
|
|
//setup IO
|
||
|
|
pinMode(FOOTSWITCH, INPUT_PULLUP);
|
||
|
|
pinMode(TOGGLE, INPUT_PULLUP);
|
||
|
|
pinMode(PUSHBUTTON_1, INPUT_PULLUP);
|
||
|
|
pinMode(PUSHBUTTON_2, INPUT_PULLUP);
|
||
|
|
pinMode(LED, OUTPUT);
|
||
|
|
|
||
|
|
// setup ADC
|
||
|
|
ADMUX = 0x60; // left adjust, adc0, internal vcc
|
||
|
|
ADCSRA = 0xe5; // turn on adc, ck/32, auto trigger
|
||
|
|
ADCSRB = 0x07; // t1 capture for trigger
|
||
|
|
DIDR0 = 0x01; // turn off digital inputs for adc0
|
||
|
|
|
||
|
|
// setup PWM
|
||
|
|
TCCR1A = (((PWM_QTY - 1) << 5) | 0x80 | (PWM_MODE << 1)); //
|
||
|
|
TCCR1B = ((PWM_MODE << 3) | 0x11); // ck/1
|
||
|
|
TIMSK1 = 0x20; // interrupt on capture interrupt
|
||
|
|
ICR1H = (PWM_FREQ >> 8);
|
||
|
|
ICR1L = (PWM_FREQ & 0xff);
|
||
|
|
DDRB |= ((PWM_QTY << 1) | 0x02); // turn on outputs
|
||
|
|
sei(); // turn on interrupts - not really necessary with arduino
|
||
|
|
}
|
||
|
|
|
||
|
|
void loop()
|
||
|
|
{
|
||
|
|
//Turn on the LED if the effect is ON.
|
||
|
|
if (digitalRead(FOOTSWITCH)) digitalWrite(LED, HIGH);
|
||
|
|
else digitalWrite(LED, LOW);
|
||
|
|
//nothing here, all happens in the Timer 1 interruption.
|
||
|
|
}
|
||
|
|
|
||
|
|
ISR(TIMER1_CAPT_vect)
|
||
|
|
{
|
||
|
|
// get ADC data
|
||
|
|
ADC_low = ADCL; // you need to fetch the low byte first
|
||
|
|
ADC_high = ADCH;
|
||
|
|
//construct the input sumple summing the ADC low and high byte.
|
||
|
|
input = ((ADC_high << 8) | ADC_low) + 0x8000; // make a signed 16b value
|
||
|
|
|
||
|
|
//// All the Digital Signal Processing happens here: ////
|
||
|
|
|
||
|
|
counter++; //to save resources, the pushbuttons are checked every 10000 times.
|
||
|
|
if(counter==10000)
|
||
|
|
{
|
||
|
|
counter=0;
|
||
|
|
if (!digitalRead(PUSHBUTTON_2)) {
|
||
|
|
if (bit_crush_variable<16)bit_crush_variable=bit_crush_variable+1; //increase the vol
|
||
|
|
digitalWrite(LED, LOW); //blinks the led
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!digitalRead(PUSHBUTTON_1)) {
|
||
|
|
if (bit_crush_variable>0)bit_crush_variable=bit_crush_variable-1; //decrease vol
|
||
|
|
digitalWrite(LED, LOW); //blinks the led
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
//The bit_crush_variable goes from 0 to 16 and the input signal is crushed in the next instruction:
|
||
|
|
input = input<<bit_crush_variable;
|
||
|
|
|
||
|
|
//write the PWM signal
|
||
|
|
OCR1AL = ((input + 0x8000) >> 8); // convert to unsigned, send out high byte
|
||
|
|
OCR1BL = input; // send out low byte
|
||
|
|
}
|