// VLSI 1053 codec Structure generator //

/*

 Based recursive Cellular Automata 

 Pot0 = chain note A
 Pot1 = chain note B
 Pot2 = chain instrument
 Pot3 = chain drum
 Pot4 = tempo/speed 45 - 350 BPM 16th note

 Channel 1-x random voices
 Channel 10 drums
 
 Created by JLS 2019

 */

#include <SPI.h>
#include <MIDI.h>

#define MAXTEMPO  14 // 350 BPM 16th note
#define MINTEMPO 111 // 45 BPM 16th note

  MIDI_CREATE_DEFAULT_INSTANCE();

  #define WIDTH  256
  
  int xx;
  byte k;
  int state[WIDTH];
  
  int delay_ms = 0;

  //SCI_MODE register defines
  #define SM_DIFF           0
  #define SM_LAYER12        1
  #define SM_RESET          2
  #define SM_CANCEL         3
  #define SM_EARSPEAKER_LO  4
  #define SM_TESTS          5
  #define SM_STREAM         6
  #define SM_EARSPEAKER_HI  7
  #define SM_DACT           8
  #define SM_SDIORD         9
  #define SM_SDISHARE       10
  #define SM_SDINEW         11
  #define SM_ADPCM          12
  #define SM_ADPCM_HP       13
  #define SM_LINE1          14
  #define SM_CLK_RANGE      15

 
void cs_low()
{
  digitalWrite(9, LOW); // CS low
  delayMicroseconds(250);
}


void cs_high()
{
  digitalWrite(9, HIGH); // CS high
  delayMicroseconds(250);
}
 
 
void sci_write(char address, int data)
{
  cs_low();
 
  SPI.transfer(0x02); //send write command
  SPI.transfer(address); //send address we are going to write to

  SPI.transfer((data >> 8) & 0xFF); //send the first 8 MSBs of the data
  SPI.transfer(data & 0xFF); //send the LSBs
  
  cs_high();
}


void sci_volume (char volleft, char volright)
{
  cs_low();
  
  SPI.transfer(0x02);
  SPI.transfer(0x0B);
  SPI.transfer(volleft);
  SPI.transfer(volright);
  
  cs_high();
}


void sci_bass (char treble, char bass)
{
  cs_low();
  
  SPI.transfer(0x02);
  SPI.transfer(0x02);
  SPI.transfer(treble);
  SPI.transfer(bass);
  
  cs_high();
}


void setup()
{
  
  MIDI.begin ();
  
  pinMode (9,OUTPUT); // pin9 = CS
  
  SPI.begin();
  SPI.setDataMode(SPI_MODE1);
  SPI.setClockDivider(SPI_CLOCK_DIV2);
  
  SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR1)|(1<<SPR0); // spi clock rate to fck/4
  
  sci_write(0x00,(1<<SM_TESTS)|(1<<SM_SDISHARE)|(1<<SM_SDINEW)|(0<<SM_DIFF)|(0<<SM_CLK_RANGE)|(0<<SM_EARSPEAKER_LO)|(0<<SM_EARSPEAKER_HI)); // SCI_MODE initialise
  
  sci_volume(0x1A,0x1A); // left, right volume 0xFE-0x0
  
  sci_bass(0x00,0x00); // treble, bass

  sci_write (0x03,0x8BE8);
  
  sci_write (0x07,0x8050);
  sci_write (0x06,0x0030);
  sci_write (0x06,0x0715);
  sci_write (0x06,0xb080);
  sci_write (0x06,0x3400);
  sci_write (0x06,0x0007);
  sci_write (0x06,0x9255);
  sci_write (0x06,0x3d00);
  sci_write (0x06,0x0024);
  sci_write (0x06,0x0030);
  sci_write (0x06,0x0295);
  sci_write (0x06,0x6890);
  sci_write (0x06,0x3400);
  sci_write (0x06,0x0030);
  sci_write (0x06,0x0495);
  sci_write (0x06,0x3d00);
  sci_write (0x06,0x0024);
  sci_write (0x06,0x2908);
  sci_write (0x06,0x4d40);
  sci_write (0x06,0x0030);
  sci_write (0x06,0x0200);
  sci_write (0x0A,0x0050);
  
  sci_write (0x07,0x1e03);
  sci_write (0x06,0x0F);


  randomSeed(analogRead(0) * analogRead(1));
    
  for (xx=0;xx<WIDTH;xx++) state[xx] = random(16);
   
}


void loop() 
{

  k = k^state[xx]^state[k];
        
  state[xx] = k;
  
  int note_a = 24 + ((analogRead(0) * (4*k)) / analogRead(0));
  int note_b = 36 + ((analogRead(1) * (3*k)) / analogRead(1));
  int note_c = note_a ^ note_b;
  int drum = 35 + ((analogRead(3) * (3*k) / analogRead(3)));

  if (k != 10) MIDI.sendProgramChange ((analogRead(2)/k)>>2, k);
  
  int aa = k;
  int bb = (k+1)%16;
  int cc = aa ^ bb;

  MIDI.sendNoteOn (note_a, 24 + random(k*5), aa);
  MIDI.sendNoteOn (note_b, 24 + random(k*5), bb);
  MIDI.sendNoteOn (note_c, 24 + random(k*5), cc);
  MIDI.sendNoteOn (drum, 48 + random(k*3), 10);

  delay_ms = map(analogRead(4), 0, 1023, MINTEMPO, MAXTEMPO); 

  delay (2 * delay_ms);

  MIDI.sendNoteOff (note_a, 0, aa);
  MIDI.sendNoteOff (note_b, 0, bb);
  MIDI.sendNoteOff (note_c, 0, cc);
      
  delay (delay_ms);

  if (xx == WIDTH) xx = 0;

  xx++;
   
}