#include <Arduino.h>
#include <Wire.h>
#include <SPI.h>

#define mosi 23
#define miso 19
#define sclk 18
#define cs   5
#define rst  17
#define rdy  16

#define SPISPEED 1000000 //  1.92MHz std.@ 7.68/4 MHz

const float Vref = 2.485;

void sendAds ()
{
  unsigned long adc_val[8] = {0,0,0,0,0,0,0,0};
  byte mux[8] = {0x08,0x18,0x28,0x38,0x48,0x58,0x68,0x78};
  
  int i = 0;

  SPI.beginTransaction(SPISettings(SPISPEED, MSBFIRST, SPI_MODE1));
  digitalWrite(cs, LOW);
  delayMicroseconds(1);

  for (i=0; i <= 7; i++)
  {
    byte channel = mux[i];
    
    while (digitalRead(rdy)) {} ;                          

    SPI.transfer(0x50 | 0x01);
    SPI.transfer(0x00);
    SPI.transfer(channel);
    delayMicroseconds(2);

    SPI.transfer(0xFC);
    delayMicroseconds(2);

    SPI.transfer(0x00);
    delayMicroseconds(250);
    
    SPI.transfer(0x01);
    delayMicroseconds(7);
    
    adc_val[i] = SPI.transfer(0);
    adc_val[i] <<= 8;
    adc_val[i] |= SPI.transfer(0);
    adc_val[i] <<= 8;
    adc_val[i] |= SPI.transfer(0);

    delayMicroseconds(1);

  }
  
  digitalWrite(cs, HIGH);
  SPI.endTransaction();

  for (i=0; i <= 7; i++)
  {

    if(adc_val[i] > 0x7fffff)
    {
      adc_val[i] = 16777216ul-adc_val[i];
    }

  }

  double FV0 = adc_val[0] * 2 * Vref / 8388607 ;
  double FV1 = adc_val[1] * 2 * Vref / 8388607 ;
  double FV2 = adc_val[2] * 2 * Vref / 8388607 ;
  double FV3 = adc_val[3] * 2 * Vref / 8388607 ;
  double FV4 = adc_val[4] * 2 * Vref / 8388607 ;
  double FV5 = adc_val[5] * 2 * Vref / 8388607 ;
  double FV6 = adc_val[6] * 2 * Vref / 8388607 ;
  double FV7 = adc_val[7] * 2 * Vref / 8388607 ;

  delay(1);

}

void setup()
{
  Serial.begin(115200);
  delay(100);

  pinMode(cs, OUTPUT);
  digitalWrite(cs, LOW);
  pinMode(rdy, INPUT);
  pinMode(rst, OUTPUT);
  digitalWrite(rst, LOW);
  delay(1);
  digitalWrite(rst, HIGH);
  
  delay(500);
  SPI.begin();
  delay(500);

  digitalWrite(cs, LOW);

  while (digitalRead(rdy)) {}
  SPI.beginTransaction(SPISettings(SPISPEED, MSBFIRST, SPI_MODE1));
  digitalWrite(cs, LOW);
  delayMicroseconds(10);

  SPI.transfer(0xFE);
  delay(10);

  byte status_reg = 0x00 ;
  byte status_data = 0x07;
  SPI.transfer(0x50 | status_reg);
  SPI.transfer(0x00);
  SPI.transfer(status_data);
  delayMicroseconds(10);

  byte adcon_reg = 0x02;
  byte adcon_data = 0x00;
  SPI.transfer(0x50 | adcon_reg);
  SPI.transfer(0x00);
  SPI.transfer(adcon_data);
  delayMicroseconds(10);

  byte drate_reg = 0x03;
  byte drate_data = 0xF0;
  SPI.transfer(0x50 | drate_reg);
  SPI.transfer(0x00);
  SPI.transfer(drate_data);
  delayMicroseconds(10);

  SPI.transfer(0xF0);
  delay(400);
  digitalWrite(cs, HIGH);
  SPI.endTransaction();

  while (!Serial && (millis ()  <=  5000));
  Serial.println("configured, starting");
  Serial.println("");
  Serial.println("A0,A1,A2,A3,A4,A5,A6,A7");
    
  terminal.flush();
  terminal.clear();         

  timer.setInterval(1000L, sendAds);
    
}

void loop()
{
  timer.run();
}