/*------------ Schroeder’s reverberator  ---------------*/
//======================================================================================================//
// FOOTSWITCH ------------------ TURN ON/OFF THE EFFECT
// MIX SWITCH ------------- [ON] ADD ORIGINAL SOUND, [OFF] ONLY EFFECT
//======================================================================================================//
//
//Based on :[1] www.electrosmash.com/pedalshield configurations,
//          [2] AES Brasil 2011 - article "Filtros e Efeitos de Áudio Analógicos e Digitais"
//          [3] Zolzer, U.; “DAFX: Digital Audio Effects” John Wiley & Sons, Ltd – 2002.
//          [4] Oppenheim, A., V.; “Applications of Digital Signal Processing”, ”, Prentice Hall, 1978.
//          [6] Schroeder; M. R., “Natural Sounding Artificial reverberation” J. Audio Eng. Soc, 10; 1962.
//          [7] Orfanidis, S. J.; “Introduction to Signal processing”, Prentice Hall, 2009.
//
// Developed by Andrew Henrique Pavei, (This email address is being protected from spambots. You need JavaScript enabled to view it.), as part of the Final Paper to 
//Electrical Engeneering Graduation of Federal University of Santa Catarina (UFSC), Brazil and AES Brazil 2016 
//LECTURE "Implementações de Efeitos de Áudio utilizando Arduino DUE e PedalSHIELD"
//======================================================================================================//
// In development, Delays and gains based on MATLAB Code of [2].
// Schroeder’s Reverberator Functions :
//                                      x1(n) = x(n) + a1.x1(n-D1)                  [138]
//                                      x2(n) = x(n) + a2.x2(n-D2)                  [139]
//          Comb Filters IIR            x3(n) = x(n) + a3.x3(n-D3)                  [140]
//                                      x4(n) = x(n) + a4.x4(n-D4)                  [141]
//
//                                      x5(n) = [b1.x1(n) + b2.x2(n) + b3.x3(n) + b4.x4(n)]/4
//
//          All-pass Filters            x6(n) = a5.x6(n-D5) - a5.x5(n) + x5(n-D5)   [142]
//                                      y(n) = a6.y(n-D6) - a6.x6(n) + x6(n-D6)     [143]
//
//======================================================================================================//
 #include <fix16.h>
                        //  8k  16k
#define D1   2000       //  238 476
#define D2   2000       //  297 594
#define D3   2000       //  329 658
#define D4   2000       //  350 700
#define D5   4000       //  775 1550   
#define D6   2000      //  263 526 

 
  int DV1 = 560;
  int DV2 = 1184;
  int DV3 = 656;
  int DV4 = 704;
  int DV5 = 1552;
  int DV6 = 528;
 
 
int in_ADC0, in_ADC1;  //variables for 2 ADCs values (ADC0, ADC1)
int POT0, POT1, POT2, out_DAC0, out_DAC1; //variables for 3 pots (ADC8, ADC9, ADC10)
int LED = 3;
int FOOTSWITCH = 7;
int TOGGLE = 2;
 
fix16_t in0,in1,out0,out1;
 
fix16_t a1 = 46393, a2 = 42572, a3 = 40632, a4 = 39426, a5 = 48064, a6 = 43673;
fix16_t b1 = 64881, b2 = 62259 , b3 = 58982 , b4 = 52429;
int index5 = 0, index6 = 0;
 
int temp1 = 0, temp2 = 0, temp3 = 0,temp4 = 0,temp5 = 0,temp6 = 0;
 
fix16_t X1[D1] = {0};
fix16_t X2[D2] = {0};
fix16_t X3[D3] = {0};
fix16_t X4[D4] = {0};
fix16_t X5[D5] = {0};
fix16_t X6[D6] = {0};
 
fix16_t S1 = 0, S2 =  0, S3 =  0, S4 =  0, S5 = 0, S6 = 0, S7 = 0, S51 = 0;
 
int DC1 = 0, DC2 = 0, DC3 = 0, DC4 = 0, DC5 = 1, DC6 = 1;
 
int toggle_value = 0;
int effect=0;
 
void setup()
{
 //Serial.begin(9600);
  //turn on the timer clock in the power management controller
  pmc_set_writeprotect(false);
  pmc_enable_periph_clk(ID_TC4);
 
  //we want wavesel 01 with RC
  TC_Configure(TC1, 1, TC_CMR_WAVE | TC_CMR_WAVSEL_UP_RC | TC_CMR_TCCLKS_TIMER_CLOCK2);
  TC_SetRC(TC1, 1, 656 ); // sets <> 8 Khz interrupt rate
  //8KHz,  value = 1312 (10500000/8000 = 1312) --------------- 8KHz (1/8KHz = 125us)
  //16KHz, value = 656 (10500000/16000 = 656)
  //32KHz, value = 328 (10500000/32000 = 328)
  //44.1Hz, value = 238 (10500000/44100 = 238) -------------- 44.1KHz (1/44KHz=22.6us)
  //48KHz, value = 218 (10500000/48000 = 218)
  //88.2KHz, value = 119 (10500000/88200 = 119)
  //96KHz, value = 109  (10500000/96000 = 109)
 
  TC_Start(TC1, 1);
 
  // enable timer interrupts on the timer
  TC1->TC_CHANNEL[1].TC_IER = TC_IER_CPCS;
  TC1->TC_CHANNEL[1].TC_IDR = ~TC_IER_CPCS;
 
  //Enable the interrupt in the nested vector interrupt controller
  //TC4_IRQn where 4 is the timer number * timer channels (3) + the channel number
  //(=(1*3)+1) for timer1 channel1
  NVIC_EnableIRQ(TC4_IRQn);
 
  //ADC Configuration
  ADC->ADC_MR |= 0x80;   // DAC in free running mode.
  ADC->ADC_CR = 2;       // Starts ADC conversion.
  ADC->ADC_CHER = 0x1CC0; // Enable ADC channels 0,1,8,9 and 10
 
  //DAC Configuration
  analogWrite(DAC0, 0); // Enables DAC0
  analogWrite(DAC1, 0); // Enables DAC0
  //pedalSHIELD pin configuration
  pinMode(LED, OUTPUT);
  pinMode(FOOTSWITCH, INPUT_PULLUP);
  pinMode(TOGGLE, INPUT_PULLUP);
  attachInterrupt(TOGGLE, switch_handler, CHANGE);
 
}
 
void loop()
{
 
  //Read the ADCs
  while ((ADC->ADC_ISR & 0x1CC0) != 0x1CC0); // wait for ADC 0, 1, 8, 9, 10 conversion complete.
  in_ADC0 = ADC->ADC_CDR[7];             // read data from ADC0
  POT0 = ADC->ADC_CDR[10];               // read data from ADC8
  POT1 = ADC->ADC_CDR[11];               // read data from ADC9
  POT2 = ADC->ADC_CDR[12];               // read data from ADC10
//Serial.println(effect);
}
 
 
//Interrupt at 8KHz rate (every 125us)
void TC4_Handler()
{
  //Clear status allowing the interrupt to be fired again.
  TC_GetStatus(TC1, 1);
 
  if (effect==0)
{ 
 
   DV1 = 560;
   DV2 = 1184;
   DV3 = 656;
   DV4 = 704;
   DV5 = 1552;
   DV6 = 528;
  digitalWrite(LED, HIGH);
//  digitalWrite(48, HIGH);
//  digitalWrite(49, HIGH);
 
}
 
if (effect==1)
{ 
   DV1 = 863;
   DV2 = 1583;
   DV3 = 957;
   DV4 = 1003;
   DV5 = 1557;
   DV6 = 1523;
  digitalWrite(LED, HIGH);
//  digitalWrite(48, HIGH);
//  digitalWrite(49, HIGH);
 
}
if (effect==2) {
//  DV1 = map(POT0>>1,0,2047,1,2000);
//  DV2 = map(POT1>>1,0,2047,1,2000);
//  DV3 = map(POT2>>1,0,2047,1,2000); 
  temp1 = map(POT0>>1,0,2047,1,2000);
  temp2 = map(POT1>>1,0,2047,1,2000);
  temp3 = map(POT2>>1,0,2047,1,2000);  
   digitalWrite(LED, LOW);
//   digitalWrite(48, HIGH);
//   digitalWrite(49, LOW);
  if(temp1 > DV1)
    DV1++;
  else if(temp1 < DV1)
    DV1--;
 
  if(temp2 > DV2)
    DV2++;
  else if(temp2 < DV2)
    DV2--;
 
    if(temp3 > DV3)
    DV3++;
  else if(temp3 < DV3)
    DV3--;
}
if (effect==3) {
    temp4 = map(POT0>>1,0,2047,1,2000);
    temp5 = map(POT1>>1,0,2047,1,4000);
    temp6 = map(POT2>>1,0,2047,1,2000);
  if(temp4 > DV4)
    DV4++;
  else if(temp4 < DV4)
    DV4--;
 
  if(temp5 > DV5)
    DV5++;
  else if(temp5 < DV5)
    DV5--;
 
    if(temp6 > DV6)
    DV6++;
  else if(temp6 < DV3)
    DV3--;
 
 
  digitalWrite(LED, LOW);
//  digitalWrite(48, LOW);
//  digitalWrite(49, HIGH);
}
 
  in0 = in_ADC0<<16;
 
  X1[DC1] = fix16_add(in0,fix16_mul(a1,X1[DC1]));
  X2[DC2] = fix16_add(in0,fix16_mul(a2,X2[DC2]));
  X3[DC3] = fix16_add(in0,fix16_mul(a3,X3[DC3]));
  X4[DC4] = fix16_add(in0,fix16_mul(a4,X4[DC4]));
 
  S1 = fix16_mul(b1,X1[DC1]);
  S2 = fix16_mul(b2,X2[DC2]);
  S3 = fix16_mul(b3,X3[DC3]);
  S4 = fix16_mul(b4,X4[DC4]);
 
  DC1++; if (DC1 >= DV1) DC1 = 0;
  DC2++; if (DC2 >= DV2) DC2 = 0;
  DC3++; if (DC3 >= DV3) DC3 = 0;
  DC4++; if (DC4 >= DV4) DC4 = 0;
 
S5 = fix16_div(fix16_add(fix16_add(S1,S2),fix16_add(S3,S4)),262144);
// S5 = (S1 + S2 + S3 + S4)/4; <<< equivalente
 
  X5[index5] = fix16_add(S5, fix16_mul(a5, X5[DC5]));
  S6 = fix16_add(fix16_mul(fix16_sub(0,a5),X5[index5]),X5[DC5]);
 
  DC5++; if (DC5 >= DV5) DC5 = 0;
  index5++; if (index5 >= DV5) index5 = 0;
 
  X6[index6] = fix16_add(S6, fix16_mul(a6, X6[DC6]));
  //X6[index6] = (S6 + a6 * X6[DC6]);
  S7 = fix16_add(fix16_mul(fix16_sub(0,a6),X6[index6]),X6[DC6]);
  //S7 = -a6 * X6[index6] + X6[DC6];
 
  DC6++; if (DC6 >= DV6) DC6 = 0;
  index6++; if (index6 >= DV6) index6 = 0;
 
  out0 = S7;
  out_DAC0 = out0>>14;
 
  //Write the DACs
  dacc_set_channel_selection(DACC_INTERFACE, 0);        //select DAC channel 0
  dacc_write_conversion_data(DACC_INTERFACE, out_DAC0); //write on DAC
//  dacc_set_channel_selection(DACC_INTERFACE, 1);        //select DAC channel 0
//  dacc_write_conversion_data(DACC_INTERFACE, out_DAC1); //write on DAC
}
void switch_handler()
{
  delayMicroseconds(100000); //debouncing protection
  if (toggle_value!=digitalRead(TOGGLE)) effect++;
  delayMicroseconds(100000); //debouncing protection
  toggle_value=digitalRead(TOGGLE);
  if (effect==4) effect=0;
}