/* This routine used SCI to read three thermocouples whose
signals are processed by a MAX6675 conditioner.

To share the fixed call we generate three CS signals and
ignore the routine generated one
*/

#include "max6675.h"
const int coldPressure = A0;   // Analog input pin that the potentiometer is attached to
const int hotPressure = A1;    // Analog input pin that the potentiometer is attached to
const int CS_0 = 5;            // we will cycle these three pins to give three channels
const int CS_1 =  6;
const int CS_2 =  7;
const int led_pin = 13;        // diagnostic - maybe used elswhwere in OS

int thermo_DO =  2;
int thermo_CLK = 3;
int thermo_CS =  4;
int tempval=0;                // read of SCI temperature was float!
int temp_1;
int temp_2;
int temp_3;
int hot_pressure=0;
int cold_pressure=0;
int enc_pulse_pin = 19;                // encoder holes 4 degrees apart white
int once_per_rev_pin = 18; 
int piston_displacement = 0;
int data_block_1_full = 0;    // handshakes to fill/release data
int data_block_1_fill = 0;
int data_block_1[368];      // 92 entries of 4 bytes for data block
int incoming_byte;
int RPM_lockout = 0;
int ptemp=0;
int do_debug = 1;
int i;
int j;
int angle_tab[90] = {      // piston displacement % *10
  1000, 999, 995, 989, 981, 970, 957, 941, 924, 905, 883, 860, 835, 808, 780,
  750, 719, 687, 655, 621, 587, 552, 517, 483, 448, 413, 379, 346, 313, 281,
  250, 220, 192, 165, 140, 117, 96, 76, 59, 43, 30, 19, 11,  5,  1,
  0,  1,  5, 11, 19, 30, 43, 59, 76, 95, 117, 140, 165, 192, 220,
  250, 281, 313, 345, 379, 413, 448, 482, 517, 552, 587, 621, 654, 687, 719,
  750, 780, 808, 835, 860, 883, 904, 924, 941, 957, 970, 981, 989, 995, 999
};

unsigned long old_time;
unsigned long new_time;
unsigned long this_time;
unsigned long RPM = 0;

volatile int four_degree = 0;
volatile int opr = 0;      // value of once per rev pin
volatile int piston_position = 0;
MAX6675 thermocouple(thermo_CLK, thermo_CS, thermo_DO);
  
void setup() {
  pinMode(CS_0, OUTPUT);
  pinMode(CS_1, OUTPUT);
  pinMode(CS_2, OUTPUT);
  pinMode(led_pin, OUTPUT);
  pinMode(enc_pulse_pin, INPUT);
  pinMode(once_per_rev_pin, INPUT);
  attachInterrupt(4, enc, RISING);
  for (i = 0; i < 277; i = i + 1) {          // clear array
    data_block_1[i] = 0;
  }
  RPM_lockout = 0;
  do_debug=1;
  new_time = millis();
  old_time = millis();
  Serial.begin(9600);
  Serial.println("MAX6675 test");
  delay(100);  // wait for MAX chip to stabilize
}

void loop() {
      while(Serial.peek() < 0) run_debug();     // no chars are in inbuff
      run_block();
}  
  
 void run_block(){ 
   while(true){
          if (Serial.available() > 0) { 
                   incoming_byte = Serial.read();       // read the incoming byte but dont use
                   data_block_1_fill = true;            // handshake
                   if (data_block_1_full = true) {
                           for (j = 0; j < 359; j = j + 4) {     // blocks of four bytes
                               Serial.print(data_block_1[j]);
                               Serial.print(",");
                               Serial.print(data_block_1[j + 1]);
                               Serial.print(",");
                               Serial.print(data_block_1[j + 2]);
                               Serial.print(",");
                               Serial.print(data_block_1[j + 2]);
                               Serial.print(",");       
                           }
                           Serial.print("  RPM=");
                           Serial.print(RPM);
                           Serial.print("  Hot temp=");
                           Serial.print(temp_1); 
                           Serial.print("  Gas temp=");
                           Serial.print(temp_2); 
                           Serial.print("  Cold temp=");
                           Serial.print(temp_3);  
                           Serial.println("   END");   
                           data_block_1_full = false;
                           data_block_1_fill = false;
                    }
              } 
       } 
 } 
  



  // **********************  INTERRUPT ROUTINE EVERY ENCODER PULSE ****************************
  void enc(){                                // interrupt call every 4 degrees of flywheel
    opr = digitalRead(once_per_rev_pin);
    if (opr == HIGH) {                     // Top dead centre of PISTON
      four_degree = 0;                     // restart angle count
      old_time = new_time;
      new_time = millis();
      this_time = new_time - old_time;      // ms for this rev
      RPM = 60000 / (this_time);            // TO REVS/MIN
    }
   read_temps();
 //  hot_pressure = analogRead(hotPressure); 
 //  cold_pressure = analogRead(coldPressure); 
   piston_displacement = angle_tab[four_degree];

    /*  Fill data block 1 comprising
     four_degrees,hot_pressure,cold pressure, piston_displacement,
     90 times (0-89)
     */
    if (data_block_1_fill = true) {
      i = 4 * four_degree;  // only do once per
      data_block_1[i] =     four_degree;
      data_block_1[i + 1] = hot_pressure;
      data_block_1[i + 2] = cold_pressure;
      data_block_1[i + 3] = piston_displacement;
    }
    if (four_degree >= 90) {
      data_block_1_fill = false;    // handshake
      data_block_1_full = true;
    }
    ++four_degree;        // note array counts from 0
  }

void read_temps(){
 //      ** Read thermocouple 1 **
   digitalWrite(CS_0, LOW);
   digitalWrite(CS_1,HIGH);
   digitalWrite(CS_2,HIGH);
   temp_3=thermocouple.readCelsius();
   digitalWrite(CS_0, HIGH); 
   
 //      ** Read thermocouple 2 **
   digitalWrite(CS_0,HIGH);
   digitalWrite(CS_1, LOW);
   digitalWrite(CS_2,HIGH);
   temp_2=thermocouple.readCelsius();
   digitalWrite(CS_1, HIGH); 
   
//      ** Read thermocouple 3 **  
   digitalWrite(CS_0,HIGH);
   digitalWrite(CS_1,HIGH);
   digitalWrite(CS_2, LOW);
   temp_1=thermocouple.readCelsius();
   digitalWrite(CS_2, HIGH);  
   
}
/* the pressure transducer has a range of 0.5 to 4.5 volts
   this covers the range of 0 to 60 psi absolute.
   we will rescale this variable to 0 to 600 counts
   The adc has span 0f 1024 for 5 volts.  */
void read_pressures(){
   ptemp = analogRead(hotPressure);
   constrain (ptemp, 103,922);
   hot_pressure = map(ptemp,102,922,0,600);
   ptemp = analogRead(coldPressure);
   constrain (ptemp, 103,922);
   cold_pressure = map(ptemp,102,922,0,600);
     
   
   
//   hot_pressure = analogRead(hotPressure); 
//   cold_pressure = analogRead(coldPressure);   
}

void run_debug(){
      read_temps();   
      read_pressures();
      Serial.print("  Hot temp=");
      Serial.print(temp_1); 
      Serial.print("  Gas temp=");
      Serial.print(temp_2); 
      Serial.print("  Cold temp=");
      Serial.print(temp_3); 
      Serial.print("  Hot Pressure=");
      Serial.print(hot_pressure);
      Serial.print("  Cold Pressure=");
      Serial.println(cold_pressure);
      delay(500);  
}