#include <SPI.h>
#include <LiquidCrystal.h>

#define SECOND 0
#define MINUTE 1
#define HOUR   2
#define DAY    4
#define MONTH  5

#define cs 8
#define alarm 9

LiquidCrystal lcd(7, 6, 2, 3, 4, 5);
int TimeDate [7]; //second,minute,hour,null,day,month,year
int Alarm[] = {20, 30}; //h, m alarm

void setup() {
  Serial.begin(9600);
  RTC_init();
  lcd.begin(16, 2);
  pinMode(alarm, OUTPUT);
  //day(1-31), month(1-12), year(0-99), hour(0-23), minute(0-59), second(0-59)
  //  SetTimeDate(25,2,15,20,40,16);
}

char temp[20];
void loop() {
  lcd.clear();
  ReadTimeDate();
  lcd.setCursor(0, 0);
  sprintf(temp, "%02d:%02d:%02d   %02d/%02d",TimeDate[HOUR], TimeDate[MINUTE],
      TimeDate[SECOND], TimeDate[MONTH], TimeDate[DAY]);
  lcd.println(temp);
  lcd.setCursor(0, 1);
  if(Alarm[0] == TimeDate[HOUR] && Alarm[1] == TimeDate[MINUTE]) {
    lcd.println("ALARM TIME");
    digitalWrite(alarm, HIGH);
  } else {
    lcd.println("I'M A CLOCK!!   ");
    digitalWrite(alarm, LOW);
  }
  delay(1000);

}

int RTC_init(){
  pinMode(cs,OUTPUT); // chip select
  // start the SPI library:
  SPI.begin();
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE1); // both mode 1 & 3 should work
  //set control register
  digitalWrite(cs, LOW);
  SPI.transfer(0x8E);
  SPI.transfer(0x60); //60= disable Osciallator and Battery SQ wave @1hz, temp compensation, Alarms disabled
  digitalWrite(cs, HIGH);
  delay(10);
}

int SetTimeDate(int d, int mo, int y, int h, int mi, int s){
  int TimeDate [7]={
    s,mi,h,0,d,mo,y  };
  for(int i=0; i<=6;i++){
    if(i==3)
      i++;
    int b= TimeDate[i]/10;
    int a= TimeDate[i]-b*10;
    if(i==2){
      if (b==2)
        b=B00000010;
      else if (b==1)
        b=B00000001;
    }
    TimeDate[i]= a+(b<<4);

    digitalWrite(cs, LOW);
    SPI.transfer(i+0x80);
    SPI.transfer(TimeDate[i]);
    digitalWrite(cs, HIGH);
  }
}

void ReadTimeDate(){
  String temp;
  for(int i=0; i<=6;i++){
    if(i==3)
      i++;
    digitalWrite(cs, LOW);
    SPI.transfer(i+0x00);
    unsigned int n = SPI.transfer(0x00);
    digitalWrite(cs, HIGH);
    int a=n & B00001111;
    if(i==2){
      int b=(n & B00110000)>>4; //24 hour mode
      if(b==B00000010)
        b=20;
      else if(b==B00000001)
        b=10;
      TimeDate[i]=a+b;
    }
    else if(i==4){
      int b=(n & B00110000)>>4;
      TimeDate[i]=a+b*10;
    }
    else if(i==5){
      int b=(n & B00010000)>>4;
      TimeDate[i]=a+b*10;
    }
    else if(i==6){
      int b=(n & B11110000)>>4;
      TimeDate[i]=a+b*10;
    }
    else{
      int b=(n & B01110000)>>4;
      TimeDate[i]=a+b*10;
    }
  }
}

String ReadTime(){
  String temp;
  temp.concat(TimeDate[2]);
  temp.concat(":");
  temp.concat(TimeDate[1]);
  temp.concat(":");
  temp.concat(TimeDate[0]);
  while(temp.length() < 17)
    temp.concat(" ");

  return temp;
}

String ReadDate(){
  String temp;
  temp.concat(TimeDate[4]);
  temp.concat("/") ;
  temp.concat(TimeDate[5]);
  temp.concat("/") ;
  temp.concat(TimeDate[6]);
  while(temp.length() < 17)
    temp.concat(" ");
  return(temp);
}