#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_ADS1X15.h>

char buffer [320];

// Pin definitions for the switch matrix
const int ROW_PINS[8] = {2, 3, 4, 5, 6, 7, 8, 9};
const int COL_PINS[8] = {10, 11, 12, 13, 14, 15, 16, 17};

// Variable to store the 16 bit integer ADC values
static int16_t analogValues[16] =  {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

// Pin definitions for the channel multiplexer
const int MUX_S0 = 18;
const int MUX_S1 = 19;
const int MUX_S2 = 20;
const int MUX_S3 = 21;
const int MUX_SIG = 22;

// Object for the ADS1115 ADC
Adafruit_ADS1015 adc;

byte matrixValues[8] = {0,0,0,0,0,0,0,0};

// Interrupt service routine for scanning the switch matrix
void matrixScan() {
   
  // Loop through each row
  for (int row = 0; row < 8; row++) {
    Serial1.print("row: ");
    Serial1.println(row);
    // Set the current row low
    digitalWrite(ROW_PINS[row], LOW);
    
    // Read the column values
    for (int col = 0; col < 8; col++) {
          
//      Setting the nth bit to either 1 or 0 can be achieved with the following:
//     number ^= (-x ^ number) & (1 << n);
//      Bit n will be set if x is 1, and cleared if x is 0.
 
      matrixValues[row] ^= (-digitalRead(COL_PINS[col])^matrixValues[row]) & (1 << col);

    }
    
    // Set the current row high
    digitalWrite(ROW_PINS[row], HIGH);
  }
    
}

void scanAnalogs() {

  for (int i = 0; i < 16; i++) {
    digitalWrite(MUX_S0, (i & 0x1) > 0);
    digitalWrite(MUX_S1, (i & 0x2) > 0);
    digitalWrite(MUX_S2, (i & 0x4) > 0);
    digitalWrite(MUX_S3, (i & 0x8) > 0);
    
    // Read the analog value using the ADC and store it
   
    analogValues[i] = adc.readADC_SingleEnded(MUX_SIG);
   
  }

}


void setup() {

  Serial1.begin(115200);



  // Set the row pins as outputs
  for (int i = 0; i < 8; i++) {
    pinMode(ROW_PINS[i], OUTPUT);
  }
  
  // Set the column pins as inputs with pull-up resistors
  for (int i = 0; i < 8; i++) {
    pinMode(COL_PINS[i], INPUT_PULLUP);
  }
  
  // Set the pins for the channel multiplexer as outputs
  pinMode(MUX_S0, OUTPUT);
  pinMode(MUX_S1, OUTPUT);
  pinMode(MUX_S2, OUTPUT);
  pinMode(MUX_S3, OUTPUT);
  
  // Initialize the ADC
  adc.begin();
  
  // Attach the interrupt service routine for scanning the switch matrix
  //attachInterrupt(0, matrixScan, CHANGE);

}

void loop() {
  // Select one of the sixteen analog signals using the channel multiplexer

  matrixScan();
  scanAnalogs();
  
  // Print the values of the switches and analog inputs
  for (int i = 0; i < 8; i++) {
    sprintf(buffer, "(%d, %d) ", i, matrixValues[i]);
    Serial1.print(buffer); 
  }
  Serial1.println();  

  for (int i = 0; i < 16; i++) {
    sprintf(buffer, "(%d, %d) ", i, analogValues[i]);
    Serial1.print(buffer); 
  }
  Serial1.println();  
  Serial1.println();  

  // Wait to sample again
  delay(1000);

}