Reg-RTC

[karthick.v]

Hai buddy,

              I can able to program in i2c but i can able to read and write in RTC,what are all procedures to program rtc and how to program.

[Prabakaran P M]

Hi Karthick

what microcontroller have you choosed to read the RTC register.

[karthick.v]

Hai Prabha,

               Iam working in pic16f877a

 

[Prabakaran P M]

Hi karthick

I'm not sure about what compiler you are using, my suggestion for you is to use MikroC for pic google it you can find sample code to read RTC register. It is a free software with 2KB of Code limitation.

[karthick.v]

hai duddy,

              The following is the rtc program i have an doubt in this program that why we are giving for hours    sendi2c(0x02);//////for minutes  sendi2c(0x01);////for seconds  sendi2c(0x00);//////date  sendi2c(0x04);/////month sendi2c(0x05);//////year sendi2c(0x07);///////

// RTC Interface with PIC 16F877A:

#include<pic.h>

void portconfig();

void sendi2c(char x);

char receivei2c();

void start();

void stop();

void rpstart();

void delay();

void lcd_cmd();

void cmd(char , char );

//void lcd_data(char);

char arr[ ]="TIME :  :  :  .";

char arr1[ ]="DATE :  –  –  . ";

void lcd_con(int );

void time();

void date();

int conv(int i);

void rtc_write();

void rtc_read();

int h,y;

void main()

{

int h,y,D2;

portconfig();

ADCON1=0X07;

lcd_cmd();

SSPCON=0X38;

SSPCON2=0X00;

SSPSTAT=0X80;

SSPADD=9;

 

cmd(0X80,0);

for(h=0;arr[h]!='';h++)

{

cmd(arr[h],1);

}

cmd(0XC0,0);

for(h=0;arr1[h]!='';h++)

{

cmd(arr1[h],1);

}

 

while(1)

{

time();

date();

//cmd(0X01,0);

//cmd(0X80,0);

//rtc_write();

//rtc_read();

 

}

}

//void rtc_write()

//{

//start();

//sendi2c(0XD0);

//sendi2c(0X0F);

//sendi2c('a');

//stop();

//}

//void rtc_read()

//{

//start();

//sendi2c(0xD0);

//sendi2c(0X0F);

//rpstart();

//sendi2c(0xD1);

//y=receivei2c();

//stop();

////lcd_con(y);

////cmd(0x89,0);

//}

void portconfig()

{

TRISB=0X00;

TRISE=0X00;

PORTB=0X00;

PORTE=0X00;

TRISD=0;

PORTD=0;

TRISC3=1;

TRISC4=1;

}

void lcd_cmd()

{

cmd(0x38,0);

cmd(0x0C,0);

cmd(0x06,0);

cmd(0x01,0);

cmd(0x80,0);

delay();

}

 

void cmd(char d, char e)

{

RE0=e;

RE1=0;

RE2=1;

PORTB=d;

delay();

RE2=0;

}

 

void time()

{

          //Hours

start();

sendi2c(0xD0);

sendi2c(0x02);

rpstart();

sendi2c(0xD1);

y=receivei2c();

stop();  

lcd_con(y);

cmd(0x86,0); 

 

             //Minutes

start();

sendi2c(0xD0);

sendi2c(0x01);

rpstart();

sendi2c(0xD1);

y=receivei2c();

stop();

lcd_con(y);

cmd(0x89,0);

 

             //Seconds

start();

sendi2c(0xD0);

 

rpstart();

sendi2c(0xD1);

y=receivei2c();

stop();

lcd_con(y);

cmd(0x8C,0);    

}

 

void date()

{

              //DATE

start();

sendi2c(0xD0);

sendi2c(0x04);

//stop();

rpstart();

//start();

sendi2c(0xD1);

y=receivei2c();

stop();

lcd_con(y);

cmd(0xC6,0);

 

             //MONTH

start();

sendi2c(0xD0);

sendi2c(0x05);

rpstart();

sendi2c(0xD1);

y=receivei2c();

stop();

lcd_con(y);

cmd(0xC9,0);

 

              //Year

start();

sendi2c(0xD0);

sendi2c(0x07);

rpstart();

sendi2c(0xD1);

y=receivei2c();

stop();

lcd_con(y);

cmd(0xCC,0);

}

 

void lcd_con(int i)

{

 

int D1,D2;

int temp;

temp=i;

i=(((temp&0X7F)>>4)*10+(temp&0X0F));

 

D1=i/10;

D2=i%10;

 

cmd(D1+48,1);

cmd(D2+48,1);

}

 

void delay()

{

int j;

for(j=0;j<500;j++);

}

 

char receivei2c()

{

SSPIF=0;

RCEN=1;

char rc;

while(SSPIF==0);

SSPIF=0;

rc=SSPBUF;

return rc;

}

 

void rpstart()

{

delay();

RSEN=1;

while(!SSPIF);

SSPIF=0;

}

 

void start()

{

delay();

SEN=1;

while(!SSPIF);

SSPIF=0;

}

 

void sendi2c(char x)

{

delay();

SSPBUF=x;

while(!SSPIF);

SSPIF=0;

}

 

void stop()

{

delay();

PEN=1;

while(!SSPIF);

SSPIF=0;

}

[Prabakaran P M]

DS1307 has total 64 bytes of memory area which is divided into two segments:

1. RTC Register Area
2. General Purpose RAM

0x00	Seconds
0x01	Minutes
0x02	Hours
0x03	Day
0x04	Date
0x05	Month
0x06	Year
0x07	Control
0x08  0x3F	RAM  56 x 8

Each parameters of time is stored in different address thats why we are denoting the address

 

[karthick.v]

thanks buddy for clearing my doubt and now i have a clear idea in RTC

[Prabakaran P M]

Feel free to post your doubts

[karthick.v]

Thanks buddy,I have the following questions

* In RTC why we are first writing and then reading any reason is there and what is the purpose of giving sendi2c(0x0f) in the above program

*In I2C master (receiver) & slave (transmitter) mode: what are the register value for both master & slave

SSPSTAT

SSPCON1

SSPCON2

*which tutorial is best  for reading gps and gsm

[Prabakaran P M]

Hi karthick,

 *First we are writting data to fetch the address or commands to the slave i.e first we have to send the address which we have to read and then we will read the data.Two address you have to fetch in I2C one is Slave address and another one is Register address for reading the register data.

*As far as i go through the datasheet i can't find any way to configure both master and slave mode. you can achieve it by the program logic which will change the register values accordingly.

*http://www.engineersgarage.com/embedded/pic-microcontroller-projects/interface-gsm-module-call-message-circuit

http://www.engineersgarage.com/articles/gsm-gprs-modules

http://www.engineersgarage.com/tutorials/gps-receivers-nmea-standards

http://www.engineersgarage.com/embedded/avr-microcontroller-projects/gps-interface-circuit

[karthick.v]

Sir,

my previous question was wrong what i ment was  so for  we used to write the data  by master and read the data by slave .Is it possible to read data by master and write data by slave if it is possible means what is register value for SSPSTAT,SSPCON1 and SSPCON2 for both master and slave

  

[Prabakaran P M]

Hi karthick

RTC acts as a slave here it is designed to act as a slave to provide data. if you are using two microcontrollers (any) with i2c you can make them two to act as a slave or master according to your requirements. you have to go throught he data sheet of your microcontroller to know the values to be loaded to the special function register.

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