142 lines
4.5 KiB
C++
142 lines
4.5 KiB
C++
/* Based on the flanger from openmusiclabs.com
|
|
this program does a flanger effect, and interpolates between samples
|
|
for a smoother sound output. a rampwave is used to set the variable
|
|
delay. the min and max delay times it swing between is set by MIN
|
|
and MAX. these are in samples, divide by 31.25ksps to get ms delay
|
|
times. the push buttons determines how much the ramp increments
|
|
by each time. this sets the frequency of the delay sweep, which is
|
|
min/maxed by B_MIN/B_MAX.
|
|
*/
|
|
|
|
#include "mult16x8.h"
|
|
|
|
//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
|
|
|
|
//defining FX parameters
|
|
#define MIN 2 // min delay of ~60us
|
|
#define MAX 200 // max delay of ~6ms
|
|
#define SIZE MAX+10 // data buffer size - must be more than MAX
|
|
|
|
|
|
int buffer[SIZE]; // create a data buffer
|
|
byte dir = 1; // keeps track of up/down counting
|
|
unsigned int location = 0; // incoming data buffer pointer
|
|
byte button; // button checking timer
|
|
byte counter = 4; // button counter (and start value)
|
|
unsigned int fractional = 0x00; // fractional sample position
|
|
int data_buffer; // temporary data storage to give a 1 sample buffer
|
|
|
|
int toggle_position=0;
|
|
int counter2=0; //buttons timer counter
|
|
|
|
|
|
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() {
|
|
if (digitalRead(FOOTSWITCH)) digitalWrite(LED, HIGH);
|
|
else digitalWrite(LED, LOW);}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
ISR(TIMER1_CAPT_vect) { // all processing happens here
|
|
|
|
// output the last value calculated
|
|
OCR1AL = ((data_buffer + 0x8000) >> 8); // convert to unsigned, send out high byte
|
|
OCR1BL = data_buffer; // send out low byte
|
|
|
|
// get ADC data
|
|
byte temp1 = ADCL; // you need to fetch the low byte first
|
|
byte temp2 = ADCH; // yes it needs to be done this way
|
|
int input = ((temp2 << 8) | temp1) + 0x8000; // make a signed 16b value
|
|
|
|
//BUTTONS
|
|
counter2++; //to save resources, the pushbuttons are checked every 2000 times.
|
|
if(counter2==2000)
|
|
{
|
|
counter2=0;
|
|
if (!digitalRead(PUSHBUTTON_1)) {
|
|
if (counter > MIN) counter-=1; // if not at min, decrement
|
|
}
|
|
if (!digitalRead(PUSHBUTTON_2)) {
|
|
if (counter < MAX) counter+=1; // if not at max, increment
|
|
}
|
|
|
|
//toggle switch
|
|
{
|
|
toggle_position = digitalRead(TOGGLE);
|
|
}
|
|
}
|
|
|
|
|
|
// fetch/store data
|
|
buffer[location] = input; // store current sample
|
|
location++; // go to next sample position
|
|
if (location >= SIZE) location = 0; // deal with buffer wrap
|
|
int temp = location - (fractional >> 8); // find delayed sample
|
|
if (temp < 0) temp += SIZE; // deal with buffer wrap
|
|
int output = buffer[temp]; // fetch delayed sample
|
|
if (toggle_position=1) output = buffer[temp]+input;
|
|
if (toggle_position=0) output = buffer[temp];
|
|
temp -= 1; // find adjacent sample
|
|
if (temp < 0) temp += SIZE; // deal with buffer wrap
|
|
int output2 = buffer[temp]; // get adjacent sample
|
|
if (toggle_position=1) output2 = buffer[temp]+input;
|
|
if (toggle_position=0) output2 = buffer[temp];
|
|
|
|
// interpolate between adjacent samples
|
|
int temp4; // create some temp variables
|
|
int temp5;
|
|
|
|
// multiply by distance to fractional position
|
|
MultiSU16X8toH16(temp4, output, (0xff - (fractional & 0x00ff)));
|
|
MultiSU16X8toH16(temp5, output2, (fractional & 0x00ff));
|
|
output = temp4 + temp5; // sum weighted samples
|
|
|
|
// save value for playback next interrupt
|
|
data_buffer = output;
|
|
|
|
// up or down count as necessary till MIN/MAX is reached
|
|
if (dir) {
|
|
if ((fractional >> 8) >= MAX) dir = 0;
|
|
fractional += counter;
|
|
}
|
|
else {
|
|
if ((fractional >> 8) <= MIN) dir = 1;
|
|
fractional -= counter;;
|
|
}
|
|
}
|