/*

##########################################################
||                                                      ||
||   Title: Serial Read with a 74HC595 Shift Register   ||
||                     Name: GC1CEO                     ||
||                   Date: 09/17/2024                   ||
||                     Attribution:                     ||
||          Based on shiftOutCode, Serial Read          ||
||       by Carlyn Maw,Tom Igoe, David A. Mellis        ||
||         Date: 10/25/2006 Modified: 3/23/2010         ||
||                                                      ||
||                     Description:                     ||
||  This program takes in a serial input of 0 through   ||
||7 and turns on that specific LED (0 - 7) while turning||
||                    off the rest.                     ||
||                                                      ||
##########################################################

*/

//Pin connected to ST_CP (Storage Clock / Latch) of 74HC595
int latchPin = 8;
//Pin connected to SH_CP (Shift Clock) of 74HC595
int clockPin = 12;
////Pin connected to DS / SER (Data/Serial Input) of 74HC595
int dataPin = 11;
////Pin connected to inverted MR / SRCLR (Master Reset / Serial Register Clear) of 74HC595
int resetPin = 10;
////Pin connected to inverted OE (Output Enable) of 74HC595
int oePin = 9;

void setup() {
  Serial.begin(9600);

  //set pins to output so you can control the shift register and setting button and pot pins to INPUT
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(resetPin, OUTPUT);
  pinMode(oePin, OUTPUT);


  // Setting reset to HIGH to stop reset and setting output enable to LOW to always enable output
  digitalWrite(resetPin, HIGH);
  digitalWrite(oePin, LOW);

  // Cleaning up serial monitor and announcing program has initalized and going to loop
 for(int a = 0; a < 25; a++){
  Serial.println("");
 }
 Serial.println("Type a number from 0 to 7.");
}
void loop() {

  if (Serial.available() > 0) {

    // ASCII '0' through '97' characters are

    // represented by the values 48 through 55.

    // so if the user types a number from 0 through 7 in ASCII,

    // you can subtract 48 to get the actual value:

    String bitToGet = Serial.readString();

    // write to the shift register with the correct bit set high:

    registerWrite(bitToGet.toInt(), HIGH);

  }

}

// This method sends bits to the shift register:

void registerWrite(int whichPin, int whichState) {

  // the bits you want to send

  byte bitsToSend = 0;

  // turn off the output so the pins don't light up

  // while you're shifting bits:

  digitalWrite(latchPin, LOW);

  // turn on the next highest bit in bitsToSend:

  bitWrite(bitsToSend, whichPin, whichState);

  // shift the bits out:

  shiftOut(dataPin, clockPin, MSBFIRST, bitsToSend);

  // turn on the output so the LEDs can light up:

  digitalWrite(latchPin, HIGH);

}