Real Time Clock(DS1307) with AVR
    Revision as of 12:33, 4 February 2015 by Amruta (Talk | contribs)

    Basics

    The Real time clock DS1307 IC basically is stand alone time clock. Well, basically we can use a micrcontroller to keep time, but the value would go off as soon as it is powered off.

    The RTC DS1307 is a handy solution to keep time all the way, when it is powered by a coin cell.

    It is uses I²C (Inter-Integrated Circuit) protocol, referred to as I-squared-C, I-two-C, or IIC for communication with the micrcontroller.Check the basics of I2C here, if are not familiar with it.

    Schematic

    [1]

    Schematic AVR Interfacing RTC.JPG

    Code

    1. /*-----------------------------------------------------------------------------
    2.          Program to demonstrate displaying of RTC on LCD
    3.   -----------------------------------------------------------------------------
    4.   note:
    5.   Refer lcd.c(lcd_4_bit.c/lcd_8_bit.c) file for Pin connections
    6.   Refer Atmega32 DataSheet for register descriptions.
    7.   ------------------------------------------------------------------------------*/
    8.  
    9.  
    10.   /* io.h contains the defnition of all ports and SFRs */
    11.   #include <avr\io.h>
    12.  
    13. #include "lcd.h"	//User defined LCD library which conatins the lcd routines
    14. #include "ds1307.h" //User defined library which conatins the RTC(ds1307) routines
    15.  
    16.  
    17. /* start the main program */
    18. void main() 
    19. {
    20.    unsigned char sec,min,hour,day,month,year;
    21.  
    22.   /* Initilize the lcd before displaying any thing on the lcd */
    23.     LCD_Init();
    24.  
    25.   /* Initilize the RTC(ds1307) before reading or writing time/date */
    26.     DS1307_Init();
    27.  
    28.  
    29.   /*Set the time and Date only once */
    30.    DS1307_SetTime(0x10,0x40,0x20);  //  10:40:20 am
    31.    DS1307_SetDate(0x14,0x11,0x12);  //  14th Nov 2012
    32.  
    33.   /* Display "Time" on first line*/
    34.   LCD_DisplayString("Time: ");
    35.  
    36.    /* Display "Date" on Second line*/
    37.   LCD_GoToLineTwo();
    38.   LCD_DisplayString("Date: ");
    39.  
    40.    /* Display the Time and Date continuously */ 
    41.    while(1)
    42.     {
    43. 	   /* Read the Time from RTC(ds1307) */ 
    44.         DS1307_GetTime(&hour,&min,&sec);        
    45.  
    46. 		/* Display the time on Firstline-7th position*/
    47.          LCD_GoToXY(0,6); 		 
    48.          LCD_DisplayRtcTime(hour,min,sec);
    49.  
    50.  
    51. 	    /* Read the Date from RTC(ds1307) */ 
    52.         DS1307_GetDate(&day,&month,&year);        
    53.  
    54. 		/* Display the Date on Secondline-7th position*/
    55.          LCD_GoToXY(1,6); 		 
    56.          LCD_DisplayRtcDate(day,month,year);
    57. 	  }		
    58.  
    59.   }
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