#include"ADC.h"
#include"lcd.h"
#include"i2c.h"
#include"RTC.h"
#include<string.h>

char sec=23;
char mints=10;
char hrs=9;
char dt=28;
char mnth=06;
char yr=24;

char str[16];
  float temp;

void setup()
{
   LCD_init();
   ADC_init();
  RTC_address(sec,mints,hrs,dt,mnth,yr); 
}

void loop()
{
  
             temp = convertToCelcius(AnalogRead());
             sprintf(str,"%02d C",(short)temp);
             GET_TIME_DATE();
             DEC_TO_STR();
             LCD_cmd(0x8B);
             LCD_string(str);
             LCD_cmd(0xc0);
             LCD_string(TIME);
             LCD_cmd(0x80);
             LCD_string(DATE);
           
}

sketch.ino

diagram.json

void LCD_data(unsigned char data )
{
   volatile char* portf_dir=(volatile char*)0x30;
  volatile char* portk_dir=(volatile char*)0x107;
   volatile char* portf_data=(volatile char*)0x31;
   volatile char* portk_data=(volatile char*)0x108;
   *portf_dir=0xf0;
   *portk_dir=0x03;

   *portf_data= (data & 0xf0);
    *portk_data=0x02;
   *portk_data=0x03;
   *portk_data=0x02;

   *portf_data=(data << 4) & 0xf0;
    *portk_data=0x02;
   *portk_data=0x3;
   *portk_data=0x02;
}

/*************************************************************************************************/

void LCD_cmd(unsigned char data)
{
   volatile char* portf_dir=(volatile char*)0x30;
  volatile char* portk_dir=(volatile char*)0x107;
   volatile char* portf_data=(volatile char*)0x31;
     volatile char* portk_data=(volatile char*)0x108;
   *portf_dir=0xf0;
   *portk_dir=0x03;

   *portf_data=(data & 0xf0);
   *portk_data=0x01;
   *portk_data=0x00;

   *portf_data=(data << 4) & 0xf0;
   *portk_data=0x01;
   *portk_data=0x00;
}

/*************************************************************************************************/

void LCD_string(char *ptr)
{
while(*ptr!='\0')
{
    LCD_data(*ptr);
    ptr++;
}
}

/*************************************************************************************************/

void LCD_init()
{
  LCD_cmd(0x02);
  LCD_cmd(0x28);
  LCD_cmd(0x0c);
  LCD_cmd(0x06);
  LCD_cmd(0x01);
}

/*************************************************************************************************/
void LCD_clear()
{
  volatile char* portf_dir = (volatile char*)0x30;
  volatile char* portk_dir = (volatile char*)0x107;
  volatile char* portf_data = (volatile char*)0x31;
  volatile char* portk_data = (volatile char*)0x108;

  *portf_data=0x01;
   *portk_data = 0x01;
  *portk_data = 0x00;
}

lcd.h

#ifndef ADC_H
#define ADC_H

typedef struct
{
    uint8_t lowByteData;       //make data to be as RIGHT JUSTIFIED
    uint8_t highByteData;
}IndividualBytes;

typedef union{
    uint16_t AD16Read;
    IndividualBytes AD8Read;    
}AnalogResult;


void ADC_init(void);
uint16_t AnalogRead(void);
float convertToCelcius(uint16_t);

#endif

ADC.h

#include <Arduino.h>
#include "ADC.h"

AnalogResult TempSensor;

void ADC_init()
{
   ADMUX = 0x40;         //result will be right justified
   ADCSRB = 0b00000000;  //ADC at free running mode, 0x00
   ADCSRA = 0b10000111;  //0x87
   DIDR0 = 1<<ADC0D;     //disabling the digital buffer in Analog input (A0)
}
uint16_t AnalogRead()
{
   ADCSRA |= (1 << ADSC);
   while (ADCSRA & (1 << ADSC));
   TempSensor.AD8Read.lowByteData = ADCL;      //storing low byte
   TempSensor.AD8Read.highByteData = ADCH;     //storing high byte
   return TempSensor.AD16Read;                 //returning as 16 bit data
}
float convertToCelcius(uint16_t analogValue)
{
    float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / 3950 + 1.0 / 298.15) - 273.15;
    return celsius;
}

ADC.ino

#define TWINT_SET 0x80                  // setting TWINT to 1
#define TWINT_EN 0x84                   // setting TWINT to 1 and Enable in TWCR
#define TWINT_EN_ACK 0xC4                   // setting TWINT to 1 and Enable in TWCR
//#define START 0x08                      // status codes for start data transfer
//#define MT_SLA_ACK 0x18                 // status codes for master slave ack transfer
#define MT_DATA_ACK 0x28                // status codes for master slave ack transfer

//#define SLA_MT_ACK 0x40                 // status codes for master slave ack transfer
#define DATA_MT_ACK 0x50                // status codes for master slave ack transfer

#define CR_A 0xbc                       // Control register address
#define SR_A 0xb9                       // Status register address
#define DR_A 0xbb                       // Data register address
#define START_CONDITION 0xA4            // initializion of I2C and start condition
#define STOP_CONDITION 0x94             // Stop conditon
#define RTC_R 0xd1                      //slave address is 0x68 for RTC
#define RTC_W 0xd0                      // Slave address + write
/*********************************************************************************/
/*********************************************************************************/

void delay1()
{
  volatile long i;
  for(i=0;i<600;i++);
}
void ERROR()
{
  LCD_cmd(80);
  LCD_string("ERROR");
}

/*********************************************************************************/

void I2C_START()                     //initiates the i2c lcd
{
   volatile char *twsr,*twcr;  
   twcr=CR_A;                            // control register address
   twsr=SR_A;                            // status register address
   *twcr=START_CONDITION;                // initialization i2c and start condition and TWI_INT is set to 1
   while(!(*twcr & TWINT_SET));          // waits until the i2c data get transferred
  // if ((*twsr & 0xF8) != START)           // checking the status codes
   //     ERROR();
}

/*********************************************************************************/

void I2C_SA_W_R_TRANSFER(char SA)               //slave address + write
{
    volatile char *twdr,*twcr,*twsr;
   twdr=DR_A;                            // data register address
   twcr=CR_A;                            // control register address
   twsr=SR_A;                            // status register address
   *twdr=SA;                             // slave address + write
   *twcr=TWINT_EN;                       // TWI_INT is set to 1 and Enble
   while(!(*twcr & TWINT_SET));          // waits until the i2c data get transferred
   //if ((*twsr & 0xF8) != MT_SLA_ACK)     // checking the status codes of Master transfer slave acknowledge
     //    {  ERROR(); }
}

/*********************************************************************************/

void I2C_DATA_W_TRANSFER(char data)    // data byte
{
   volatile char *twdr,*twcr,*twsr;
   twdr=DR_A;                            // data register address
   twcr=CR_A;                            // control register address
   twsr=SR_A;                            // status register address
   *twdr=data;                           // required data
   *twcr=TWINT_EN;                       // TWI_INT is set to 1 and enble
   while(!(*twcr & TWINT_SET));          //waits until the i2c data get transferred
   if ((*twsr & 0xF8) != MT_DATA_ACK)    // checking the status codes of Master transfer data acknowledge
         {  ERROR(); }
}

char I2C_DATA_R_TRANSFER()    // data byte
{
   volatile char *twdr,*twcr,*twsr;
   twdr=DR_A;                            // data register address
   twcr=CR_A;                            // control register address
   twsr=SR_A;                            // status register address
      *twcr=TWINT_EN_ACK;                       // TWI_INT is set to 1 and enble
   while(!(*twcr & TWINT_SET));          //waits until the i2c data get transferred
   if ((*twsr & 0xF8) != DATA_MT_ACK)    // checking the status codes of Master transfer data acknowledge
          {  ERROR(); }
     return *twdr; 
}
char I2C_DATA_R_TRANSFER1()    // data byte
{
   volatile char *twdr,*twcr,*twsr;
   twdr=DR_A;                            // data register address
   twcr=CR_A;                            // control register address
   twsr=SR_A;                            // status register address
      *twcr=TWINT_EN;                       // TWI_INT is set to 1 and enble
   while(!(*twcr & TWINT_SET));          //waits until the i2c data get transferred
   if ((*twsr & 0xF8) != DATA_MT_ACK)    // checking the status codes of Master transfer data acknowledge
          {  ERROR(); }
     return *twdr; 
}


/*********************************************************************************/

void I2C_STOP()                      //initiates the i2c lcd
{
   volatile char *twsr,*twcr;  
   twcr=CR_A;                            // control register address
   twsr=SR_A;                            // status register address
   *twcr=STOP_CONDITION;                 // initialization i2c and stop condition and TWI_INT is set to 1
}
void i2c_repeatedStart()
{
   volatile char *twsr,*twcr;  
   twcr=CR_A;                            // control register address
   twsr=SR_A; 
   I2C_START();
   while(!(*twcr & TWINT_SET)); 
}

i2c.h

#define START_ADDRESS 0x00

unsigned char TIME[20],DATE[20];
#define RTC_R 0xd1                      //slave address is 0x68 for RTC
#define RTC_W 0xd0                      // Slave address + write

unsigned char seconds=59,minutes=59,hours=12,date=1,month=1,year=20,dummy;
unsigned char BCD_DEC(unsigned char data)
{
  unsigned char BCD=data;
    BCD=BCD & 0x0f; // ones postion
    data=(data&0xf0)>>4; // tens position
    data=data*10+BCD;
    return data;
}
unsigned char DEC_BCD(unsigned char data)
{
  unsigned char dec=data;
  dec=(dec/10)<<4;
  data=data%10;
  data|=dec;
    return data;
}
void RTC_address(char sec,char mints,char hrs,char dt,char mnth,char yr)  //initialising RTC with some initial time
{

  I2C_START();
  I2C_SA_W_R_TRANSFER(RTC_W);
   I2C_DATA_W_TRANSFER(START_ADDRESS);
  I2C_DATA_W_TRANSFER(DEC_BCD(sec));
  I2C_DATA_W_TRANSFER(DEC_BCD(mints));
  I2C_DATA_W_TRANSFER(DEC_BCD(hrs));
  I2C_DATA_W_TRANSFER('0');
  I2C_DATA_W_TRANSFER(DEC_BCD(dt));
  I2C_DATA_W_TRANSFER(DEC_BCD(mnth));
  I2C_DATA_W_TRANSFER(DEC_BCD(yr));
  I2C_STOP();

}

void GET_TIME_DATE()    //reading RTC current date and time
{
 I2C_START();
  I2C_SA_W_R_TRANSFER(RTC_W);
   I2C_DATA_W_TRANSFER(START_ADDRESS);
  i2c_repeatedStart();
 I2C_SA_W_R_TRANSFER(RTC_R);
  seconds=BCD_DEC(I2C_DATA_R_TRANSFER());
  minutes=BCD_DEC(I2C_DATA_R_TRANSFER());
  hours=BCD_DEC(I2C_DATA_R_TRANSFER());
  dummy=BCD_DEC(I2C_DATA_R_TRANSFER());
  date=BCD_DEC(I2C_DATA_R_TRANSFER());
  month=BCD_DEC(I2C_DATA_R_TRANSFER());
  year=BCD_DEC(I2C_DATA_R_TRANSFER1());
  I2C_STOP();
  
}
void DEC_TO_STR()
{
   sprintf(DATE,"D:%02d-%02d-%02d",date,month,year);
   sprintf(TIME,"T:%02d:%02d:%02d",hours,minutes,seconds);
}