Circuit Designing & Firmware Development: Reading RTC DS1307 with 8051

This application describes the general hardware and software information about DS1307 Real Time Clock.

Here I am giving the hardware interfacing and c code also.

CODE

main.c

# include <8052.h>
# include "LcdV2.h"
# include "Ds1307.h"

# define DATE_INDEX     0
# define MONTH_INDEX    2
# define YEAR_INDEX     4
# define HOUR_INDEX     6
# define MIN_INDEX      8
# define SEC_INDEX      10

unsigned char gucTime[12];

unsigned char gucSec   = 0,
       gucMin   = 0,
       gucHour   = 0,
       gucDate   = 0,
       gucMonth   = 0,
       gucYear   = 0;

void ReadDateTime(void);
void DisplayDateTime(void);

void main(void)
{
 unsigned int i = 0;
 unsigned int j = 0;
 unsigned char ucButton = 0;
 unsigned char ucAscii[6];
 
 LcdInit();
 LcdGotoXy(0,0);
 LcdPuts("IIC-RTC Reader");
 LcdCmd(0x0c);
 while(1)
 {
  ReadDateTime();
  DisplayDateTime();
  for(i = 0; i < 40000; i++);
 }
}

void DisplayDateTime(void)
{
 LcdGotoXy(1,0);

LcdPutc(gucTime[DATE_INDEX]);
 LcdPutc(gucTime[DATE_INDEX + 1]);
 LcdPutc(gucTime[MONTH_INDEX]);
 LcdPutc(gucTime[MONTH_INDEX + 1]);
 LcdPutc(gucTime[YEAR_INDEX]);
 LcdPutc(gucTime[YEAR_INDEX + 1]);

LcdPuts("  ");

LcdPutc(gucTime[HOUR_INDEX]);
 LcdPutc(gucTime[HOUR_INDEX + 1]);
 LcdPutc(':');
 LcdPutc(gucTime[MIN_INDEX]);
 LcdPutc(gucTime[MIN_INDEX + 1]);
 LcdPutc(':');
 LcdPutc(gucTime[SEC_INDEX]);
 LcdPutc(gucTime[SEC_INDEX + 1]);
}

void ReadDateTime(void)
{
 unsigned char ucSec, ucMin, ucHour, ucDate, ucMonth, ucYear;
 unsigned char ucTemp;
 //unsigned char ucAscii[6];
 
 ucSec = Ds1307Get(SEC); 
 ucMin = Ds1307Get(MIN); 
 ucHour = Ds1307Get(HOUR);
 ucDate = Ds1307Get(DATE);
 ucMonth = Ds1307Get(MONTH);
 ucYear = Ds1307Get(YEAR);

ucTemp = ucSec;
 ucTemp = (ucTemp >> 4);
 ucTemp = (ucTemp + '0');
 
 
 /* Seconds Index */
 gucTime[SEC_INDEX]    = ucTemp;

ucTemp = ucSec;
 ucTemp = (ucTemp & 0x0f);
 ucTemp = (ucTemp + '0');
 
 gucTime[SEC_INDEX + 1]    = ucTemp;
 
 /* Minuts Index*/
 ucTemp = ucMin;
 ucTemp = (ucTemp >> 4);
 ucTemp = (ucTemp + '0');
 
 gucTime[MIN_INDEX]    = ucTemp;

ucTemp = ucMin;
 ucTemp = (ucTemp & 0x0f);
 ucTemp = (ucTemp + '0');
 
 gucTime[MIN_INDEX + 1]    = ucTemp;

/* Hour Index*/
 ucTemp = ucHour;
 ucTemp = (ucTemp >> 4);
 ucTemp = (ucTemp + '0');
 
 gucTime[HOUR_INDEX]    = ucTemp;

ucTemp = ucHour;
 ucTemp = (ucTemp & 0x0f);
 ucTemp = (ucTemp + '0');
 
 gucTime[HOUR_INDEX + 1]    = ucTemp;

/* Date Index*/
 ucTemp = ucDate;
 ucTemp = (ucTemp >> 4);
 ucTemp = (ucTemp + '0');
 
 gucTime[DATE_INDEX]    = ucTemp;

ucTemp = ucDate;
 ucTemp = (ucTemp & 0x0f);
 ucTemp = (ucTemp + '0');
 
 gucTime[DATE_INDEX + 1]    = ucTemp;

/* Month Index*/
 ucTemp = ucMonth;
 ucTemp = (ucTemp >> 4);
 ucTemp = (ucTemp + '0');
 
 gucTime[MONTH_INDEX]    = ucTemp;

ucTemp = ucMonth;
 ucTemp = (ucTemp & 0x0f);
 ucTemp = (ucTemp + '0');
 
 gucTime[MONTH_INDEX + 1]    = ucTemp;
  
 /* Year Index*/
 ucTemp = ucYear;
 ucTemp = (ucTemp >> 4);
 ucTemp = (ucTemp + '0');
 
 gucTime[YEAR_INDEX]    = ucTemp;

ucTemp = ucYear;
 ucTemp = (ucTemp & 0x0f);
 ucTemp = (ucTemp + '0');
 
 gucTime[YEAR_INDEX + 1]    = ucTemp;

if(ucHour >= 0x10)
 {
  if(ucHour >= 0x20)
   ucHour = ucHour - 12;       //ucHour - 6;
  else
   ucHour = ucHour - 6;
 }
 
 if(ucMin >= 0x10)
  if(ucMin >= 0x20)
   if(ucMin >= 0x30)
    if(ucMin >= 0x40)
     if(ucMin >= 0x50)
      ucMin = (ucMin - 30);
     else
      ucMin = (ucMin - 24);
    else
     ucMin = (ucMin - 18);
   else
    ucMin = (ucMin - 12);
  else
   ucMin = (ucMin - 6);
      
   
 
 gucSec = ucSec;
 gucMin = ucMin;
 gucHour = ucHour;
 gucDate = ucDate;
 gucMonth = ucMonth;
 gucYear = ucYear;
}

ds1307.h

/************************************************************************************
 
Description: This module is to interface Rtc(1307) to the microcontroller over I2c.
************************************************************************************/
# ifndef __DS1307_V1__
# define __DS1307_V1__

# include "I2cRtc.h" 
# include "LcdV2.h"

/* *************************************************************************** Macro Definitions */
# define SEC     0x00
# define MIN     0x01 
# define HOUR    0x02
# define DATE    0x04
# define MONTH   0x05
# define YEAR    0x06
# define DS1307_ID  0xD0

/* *************************************************************************************** */
unsigned char Ds1307Get(unsigned char ucAddr)
{
 unsigned char ucRet;

I2cStart();

I2cWrite(DS1307_ID + 1);
 ucRet = I2cRead();
 
    return ucRet;   
}

/* *************************************************************************************** */
void Ds1307SetTime(unsigned char ucHour, unsigned char ucMin, unsigned char ucSec)
{
 I2cStart();

I2cWrite(ucSec);
 I2cWrite(ucMin);
 I2cWrite(ucHour);

I2cStop();       
}

/* *************************************************************************************** */
void Ds1307SetDate(unsigned char ucDate, unsigned char ucMonth, unsigned char ucYear)
{
  I2cStart();

I2cWrite(ucDate);
 I2cWrite(ucMonth);
 I2cWrite(ucYear);

I2cStop();
}

/* *************************************************************************************** */
void RtcDisplay(unsigned char ucValue)
{
 unsigned char ucTemp  = 0; 
 
 ucTemp = (ucValue & 0xF0);
 ucTemp = ((ucTemp >> 4) | (0x30));

LcdPutc(ucTemp);

ucTemp = ucValue & 0x0F;
 ucTemp = ucTemp | 0x30;

LcdPutc(ucTemp);
}

/* *************************************************************************************** */
# endif

i2crtc.h

/***********************************************************************************
   Description:    This module is to interface I2c Bus.
************************************************************************************/
# ifndef __I2C_V1__
# define __I2C_V1__

/* *************************************************************************** Macro Definitions */
#define SDA   P3_7  
#define SCL   P3_6  
#define I2C_DELAY  0x0F

/* *********************************************************************************** Prototypes */
void I2cClock(void);
void I2cStart(void);
void I2cStop(void);
bit I2cWrite(unsigned char ucData);
unsigned char I2cRead(void);
void I2cAck(void);
void I2cNoAck(void);
void I2cDelay(void);

/* *********************************************************************************************** */
void I2cClock(void)
{
 I2cDelay();

SCL = 1;

I2cDelay();

SCL = 0; 
}

/* *********************************************************************************************** */
void I2cStart(void)
{

SDA = 0;

I2cDelay();

SCL = 0;
}

/* *********************************************************************************************** */
void I2cStop(void)
{
 SCL = 1;

I2cDelay();

SDA = 1;
}

/* *********************************************************************************************** */
bit I2cWrite(unsigned char ucData)
{
 bit bDataBit;  
 unsigned char i;

for(i=0;i<8;i++)  
 {
  bDataBit = ucData & 0x80; 
  SDA = bDataBit;

ucData = ucData << 1;  
 }

SDA = 1;

I2cDelay();

return bDataBit;
}

/* *********************************************************************************************** */
unsigned char I2cRead(void)
{
 bit bRdBit; 
 unsigned char i, ucData;

ucData = 0x00;

for(i = 0; i < 8; i++)
 {

SCL = 1;

I2cDelay();

bRdBit = SDA; 
  ucData = (ucData << 1);  
  ucData = (ucData | bRdBit); 
 }

return ucData;
}

/* *********************************************************************************************** */
void I2cAck()
{
 SDA = 0;

I2cDelay();

I2cClock();

SDA = 1;
}

/* *********************************************************************************************** */
void I2cNoAck(void)
{
 SDA = 1;

I2cDelay();

I2cClock();

SCL = 1;
}

/* *********************************************************************************************** */
void I2cDelay(void)
{
 unsigned char i;

for( i = 0; i < I2C_DELAY; i++);
}

# endif

Circuit Designing & Firmware Development

Pages

brock

Thursday, August 2, 2012

Reading RTC DS1307 with 8051