// --------------------------------------
// i2c basic com with PCA9555
//
// Le 20 Juin 2018 by Mej
// 
 
/////////////////////////////////////////////////////////////////////////////////////////////////////////

//Pin for monitoring loop
int Trig1 = A0;

// Wire and functions

#include <Wire.h>

void set_I2C_register(byte ADDRESS, byte REGISTER, byte VALUE)
{
  Wire.beginTransmission(ADDRESS);
  Wire.write(REGISTER);
  Wire.write(VALUE);
  Wire.endTransmission();
}

byte get_I2C_register(byte ADDRESS, byte REGISTER)
{
  Wire.beginTransmission(ADDRESS);
  Wire.write(REGISTER);
  Wire.endTransmission();
  Wire.requestFrom(ADDRESS, 1); //read 1 byte
  byte x = Wire.read();
  return x;
}

//timing monitoring variables
unsigned long t_0 = millis(); // gives time since startup in ms. Overflow after 50 days.
unsigned long t = millis();
unsigned long loop_cnt = 0; //loop count
const int D = 2500; //delay between loops in ms

/////////////////////////////////////////////////////////////////////////////////////////////////////////
//## MAX31790 ("4pin fan" controler - 6 channel) address
//Address
const byte MAX31790 =  B0100000; //  0x20
byte data, data0, data1;
 
void setup()
{
 
  Serial.begin(115200);
  delay(1000);
  while (!Serial);             // wait for serial monitor to be monitoring ^^

  //Set and scan I²C bus
  Wire.begin();
  Serial.println("\nI2C Scanning...");
  byte error, address;
  int nDevices =0;
  for(address = 16; address < 100; address++ )
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    // Copy/Pasted/Tweeked from https://playground.arduino.cc/Main/I2cScanner
    delay(1);
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
 
    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");
 
      nDevices++;
    }
    else if (error==4)
    {
      Serial.print("Unknown error at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.println(address,HEX);
    }    
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");


  //Reset MAX31790 (POR)
  set_I2C_register(MAX31790, 0x00, B01010000); //reset
  delay(100);
  //set_I2C_register(MAX31790, 0x00, B00110000); //no I²Ctime-out

  //PWM Frequency
  set_I2C_register(MAX31790, 0x01, B10111011); //25kHz
  delay(1);

  //Configuration
  data = B00001000; //PWM mode - 'Spin-up' OFF - control ON - Tach count- PWM yeah
  set_I2C_register(MAX31790, 0x02, data);
  delay(1);
  set_I2C_register(MAX31790, 0x03, data);
  delay(1);
  set_I2C_register(MAX31790, 0x04, data);
  delay(1);
  set_I2C_register(MAX31790, 0x05, data);
  delay(1);
  set_I2C_register(MAX31790, 0x06, data);
  delay(1);
  set_I2C_register(MAX31790, 0x07, data);
  delay(1);

//  //PWM
//  data0 = B00000000; // PWM=0
//  data1 = B0000000;
//  set_I2C_register(MAX31790, 0x30, data0); //Channel 1
//  set_I2C_register(MAX31790, 0x31, data1);
//  set_I2C_register(MAX31790, 0x32, data0); //Channel 2
//  set_I2C_register(MAX31790, 0x33, data1);
//  set_I2C_register(MAX31790, 0x34, data0); //Channel 3
//  set_I2C_register(MAX31790, 0x35, data1);
//  set_I2C_register(MAX31790, 0x36, data0); //Channel 5
//  set_I2C_register(MAX31790, 0x37, data1);
//  set_I2C_register(MAX31790, 0x38, data0); //Channel 5
//  set_I2C_register(MAX31790, 0x39, data1);
//  set_I2C_register(MAX31790, 0x3A, data0); //Channel 6
//  set_I2C_register(MAX31790, 0x3B, data1);


  //Pin for monitoring loop
  pinMode(Trig1, OUTPUT);
  digitalWrite(Trig1, LOW);
  
}
 
 
void loop()
{
 
  loop_cnt = loop_cnt+1;
  t_0 = millis();
  digitalWrite(Trig1, HIGH);

  // Update PWM target (9bit)
  //byte pwm0 = (loop_cnt*8)%256; //0 to 255 in 5 steps of 51
  byte pwm0 = B00000000;
  if (loop_cnt%2==0){
    pwm0 = B11001000;} //200
  else{
    pwm0 = B1100100;} //100
  byte pwm1 = B00000000; //LSB is ignored

  //Writte PWM target in registers
  set_I2C_register(MAX31790, 0x40, pwm0); //Channel 1
  set_I2C_register(MAX31790, 0x41, pwm1);
  set_I2C_register(MAX31790, 0x42, pwm0); //Channel 2
  set_I2C_register(MAX31790, 0x43, pwm1);
  set_I2C_register(MAX31790, 0x44, data0); //Channel 3
  set_I2C_register(MAX31790, 0x45, data1);
  set_I2C_register(MAX31790, 0x46, data0); //Channel 5
  set_I2C_register(MAX31790, 0x47, data1);
  set_I2C_register(MAX31790, 0x48, data0); //Channel 5
  set_I2C_register(MAX31790, 0x49, data1);
  set_I2C_register(MAX31790, 0x4A, data0); //Channel 6
  set_I2C_register(MAX31790, 0x4B, data1);

  //Read smth
  data0 = get_I2C_register(MAX31790, 0x18); //Tach1 count
  data1 = get_I2C_register(MAX31790, 0x19);
  int tach1 = data0*8+data1/32;
  data = get_I2C_register(MAX31790, 0x30);

  //Writte read User reg
  set_I2C_register(MAX31790, 0x15, B10011001);
  delay(1);
  byte check = get_I2C_register(MAX31790, 0x15);
 
  

//////////////////////////////////////////////////// print

  Serial.print(" PWM_target=");
  Serial.print(pwm0,DEC);
  Serial.print("  ");
  Serial.print(data,DEC);
  Serial.print("  ");
  Serial.print(" Tach1=");
  Serial.print(tach1,DEC);
  Serial.print("  ");
  Serial.print("  ");
  Serial.print(" Check=");
  Serial.print(check,BIN);
  Serial.print("  ");


  t = millis();
  Serial.print("t[s]= ");
  Serial.print(t/1000.0, 3);
  Serial.print("\t t_loop[ms]= ");
  Serial.println(t-t_0, DEC);

  digitalWrite(Trig1, LOW);
  delay(D);

}