//Tut from sparkfun, edited for multiple shift ins. This one works
//see 74165 data sheets for more details on how it works

/* IO Definitions ProCAT Flash*/

//#define DATA_IN  4
//#define CLK      5
//#define LATCH_EN 6

// HARDWARE CONNECTIONS
// Connect the following pins between your Arduino and the 74HC165 Breakout Board
// Connect pins A-H to 5V or GND or switches or whatever
const int data_pin = 4; // Connect Pin 11 to SER_OUT (serial data out)
const int clk_pin = 5; // Connect Pin 12 to CLK (the clock that times the shifting)
const int shld_pin = 6; // Connect Pin 8 to SH/!LD (shift or active low load)

const int ce_pin = 9; // Connect Pin 9 to !CE (clock enable, active low)

byte incoming; // Variable to store the 8 values loaded from the shift register
byte incoming2; // Variable to store the 8 values loaded from the shift register
byte incoming3; // Variable to store the 8 values loaded from the shift register



// The part that runs once
void setup() 
{                
  // Initialize serial to gain the power to obtain relevant information, 9600 baud
  Serial.begin(9600);

  // Initialize each digital pin to either output or input
  // We are commanding the shift register with each pin with the exception of the serial
  // data we get back on the data_pin line.
  pinMode(shld_pin, OUTPUT);
  pinMode(ce_pin, OUTPUT);
  pinMode(clk_pin, OUTPUT);
  pinMode(data_pin, INPUT);

  // Required initial states of these two pins according to the datasheet timing diagram
  digitalWrite(clk_pin, HIGH);
  digitalWrite(shld_pin, HIGH);

}

// The part that runs to infinity and beyond
void loop() {

  incoming = read_shift_regs(); // Read the shift register, it likes that

  // Print out the values being read from the shift register
  Serial.println("\nThe incoming values of the shift register are: ");
  Serial.print("ABCDEFGH : ");
  print_byte(incoming); // Print every 1 and 0 that correlates with A through H
  //Serial.println(incoming,BIN); // This way works too but leaves out the leading zeros

  delay(2000); // Wait for some arbitrary amount of time

}

// This code is intended to trigger the shift register to grab values from it's A-H inputs
byte read_shift_regs()
{
  byte the_shifted = 0;  // An 8 bit number to carry each bit value of A-H

  // Trigger loading the state of the A-H data lines into the shift register
  digitalWrite(shld_pin, LOW);
  delayMicroseconds(5); // Requires a delay here according to the datasheet timing diagram
  digitalWrite(shld_pin, HIGH);
  delayMicroseconds(5);

  // Required initial states of these two pins according to the datasheet timing diagram
  pinMode(clk_pin, OUTPUT);
  pinMode(data_pin, INPUT);
  digitalWrite(clk_pin, HIGH);
  digitalWrite(ce_pin, LOW); // Enable the clock

  // Get the A-H values
  result1 = shiftIn(data_pin, clk_pin, MSBFIRST);
  result2 = shiftIn(data_pin, clk_pin, MSBFIRST);
  result3 = shiftIn(data_pin, clk_pin, MSBFIRST);
  
  digitalWrite(ce_pin, HIGH); // Disable the clock

  //return the_shifted;

}

// A function that prints all the 1's and 0's of a byte, so 8 bits +or- 2
void print_byte(byte val)
{
    byte i;
    for(byte i=0; i<=7; i++)
    {
      Serial.print(val >> i & 1, BIN); // Magic bit shift, if you care look up the <<, >>, and & operators
    }
    Serial.print("\n"); // Go to the next line, do not collect $200
}
