Hi Govind!
I am using this code and using ds1307 and LCD in my project.Run this one, you’d see the results. B/w I’d be grateful if you can help me with DS12887 rtc. The codes on EG are able to initialize it successfully but aren’t able to update the clock every second. Do you have any idea about this?
Thanks and Regards,
Gaurav
/ interfacing ds1307 with AT89C51
#include<reg51.h>
void _nop_(void);
#define delay_us _nop_(); //generates 1 microsecond
#define LCD P1
sbit RS=P3^0; //connect p3.0 to rs pin of lcd
sbit EN=P3^2; //connect p3.2 to en pin of lcd
sbit RW=P3^1; //connect p3.1 to en pin of lcd
sbit SCK=P2^4; //serial clock pin
sbit SDA=P2^5; //serial data pin
#define SCKHIGH SCK=1;
#define SCKLOW SCK=0;
#define SDAHIGH SDA=1;
#define SDALOW SDA=0;
void integer_lcd(int);
void init_lcd(void);
void cmd_lcd(unsigned char);
void write_lcd(unsigned char);
void display_lcd(unsigned char *);
void delay_ms(unsigned int);
void start(void);
void stop(void);
void send_byte(unsigned char);
unsigned char receive_byte(unsigned char);
void write_i2c(unsigned char,unsigned char,unsigned char);
unsigned char read_i2c(unsigned char,unsigned char);
//clock[]={seconds,minutes,hours,day_of_week,date,month,year};
unsigned char clock[]={0x00,0x40,0x17,0x06,0x24,0x03,0x06};
unsigned char *s[]={“SUN”,”MON”,”TUE”,”WED”,”THU”,”FRI”,”SAT”};
unsigned char slave_ack,add=0,c,k;
unsigned int num;
// Real Time Clock Mode
void main(void)
{
init_lcd();
//cmd_lcd(0x01);
//display_lcd(“UTL”);
//delay_ms(1000);
while(add<=6) //update real time clock
{
write_i2c(0xd0,add,clock[add]);
add++;
}
// stop();
while(1)
{
c=read_i2c(0xd0,0x02);//read hours register and display on LCD
write_lcd((c/16)+48);
write_lcd((c%16)+48);
write_lcd(‘:’);
c=read_i2c(0xd0,0x01);//read minutes register and display on LCD
write_lcd((c/16)+48);
write_lcd((c%16)+48);
write_lcd(‘:’);
delay_ms(10);
c=read_i2c(0xd0,0x00);//read seconds register and display on LCD
write_lcd((c/16)+48);
write_lcd((c%16)+48);
write_lcd(‘ ‘);
display_lcd(s[read_i2c(0xd0,0x03)]);//read day register and display
cmd_lcd(0xc0);
c=read_i2c(0xd0,0x04);//read date register and display on LCD
write_lcd((c/16)+48);
write_lcd((c%16)+48);
write_lcd(‘/’);
c=read_i2c(0xd0,0x05);//read month register and display on LCD
write_lcd((c/16)+48);
write_lcd((c%16)+48);
write_lcd(‘/’);
write_lcd(‘2’);
write_lcd(‘0’);
c=read_i2c(0xd0,0x06);//read year register and display on LCD
write_lcd((c/16)+48);
write_lcd((c%16)+48);
delay_ms(100);
cmd_lcd(0x01);
}
}
//starts i2c, if both SCK & SDA are idle
void start(void)
{
if(SCK==0) //check SCK. if SCK busy, return else SCK idle
return;
if(SDA==0) //check SDA. if SDA busy, return else SDA idle
return;
SDALOW //data low
delay_us
SCKLOW //clock low
delay_us
}
//stops i2c, releasing the bus
void stop(void)
{
SDALOW //data low
SCKHIGH //clock high
delay_us
SDAHIGH //data high
delay_us
}
//transmits one byte of data to i2c bus
void send_byte(unsigned char c)
{
unsigned mask=0x80;
do //transmits 8 bits
{
if(c&mask) //set data line accordingly(0 or 1)
SDAHIGH //data high
else
SDALOW //data low
SCKHIGH //clock high
delay_us
SCKLOW //clock low
delay_us
mask/=2; //shift mask
}while(mask>0);
SDAHIGH //release data line for acknowledge
SCKHIGH //send clock for acknowledge
delay_us
slave_ack=SDA; //read data pin for acknowledge
SCKLOW //clock low
delay_us
}
//receives one byte of data from i2c bus
unsigned char receive_byte(unsigned char master_ack)
{
unsigned char c=0,mask=0x80;
do //receive 8 bits
{
SCKHIGH //clock high
delay_us
if(SDA==1) //read data
c|=mask; //store data
SCKLOW //clock low
delay_us
mask/=2; //shift mask
}while(mask>0);
if(master_ack==1)
SDAHIGH //don’t acknowledge
else
SDALOW //acknowledge
SCKHIGH //clock high
delay_us
SCKLOW //clock low
delay_us
SDAHIGH //data high
return c;
}
//writes one byte of data(c) to slave device(device_id) at given address(location)
void write_i2c(unsigned char device_id,unsigned char location,unsigned char c)
{
do
{
start(); //starts i2c bus
send_byte(device_id); //select slave device
if(slave_ack==1) //if acknowledge not received, stop i2c bus
stop();
}while(slave_ack==1); //loop until acknowledge is received
send_byte(location); //send address location
send_byte(c); //send data to i2c bus
stop(); //stop i2c bus
delay_ms(4);
}
//reads one byte of data(c) from slave device(device_id) at given address(location)
unsigned char read_i2c(unsigned char device_id,unsigned char location)
{
unsigned char c;
do
{
start(); //starts i2c bus
send_byte(device_id); //select slave device
if(slave_ack==1) //if acknowledge not received, stop i2c bus
stop();
}while(slave_ack==1); //loop until acknowledge is received
send_byte(location); //send address location
stop(); //stop i2c bus
start(); //starts i2c bus
send_byte(device_id+1); //select slave device in read mode
c=receive_byte(1); //receive data from i2c bus
stop(); //stop i2c bus
return c;
}
/*display of 16bit(integers) values on LCD
void integer_lcd(int n)
{
unsigned char c[6];
unsigned int i=0;
if(n<0)
{
write_lcd(‘-‘);
n=-n;
}
if(n==0)
write_lcd(‘0’);
while(n>0)//Split integer to 2 bytes and send on 8bit line.
{
c[i++]=(n%10)+48;
n/=10;
}
while(i–>=1)
write_lcd(c);
}*/
//initialize lcd
void init_lcd(void)
{
delay_ms(10); //delay 10 milliseconds
cmd_lcd(0x0e); //lcd on, cursor on
delay_ms(10);
cmd_lcd(0x38); //8 bit initialize, 5×7 character font, 16×2 display
delay_ms(10);
cmd_lcd(0x06); //right shift cursor automatically after each character is displayed
delay_ms(10);
cmd_lcd(0x01); //clear lcd
delay_ms(10);
cmd_lcd (0x80);
}
//transmit command or instruction to lcd
void cmd_lcd(unsigned char c)
{
EN=1;
RW=0;//set enable pin
RS=0; //clear register select pin
LCD=c; //load 8 bit data
EN=0; //clear enable pin
delay_ms(2); //delay 2 milliseconds
}
//transmit a character to be displayed on lcd
void write_lcd(unsigned char c)
{
EN=1; //set enable pin
RW=0;
RS=1; //set register select pin
LCD=c; //load 8 bit data
EN=0; //clear enable pin
delay_ms(2); //delay 2 milliseconds
}
//transmit a string to be displayed on lcd
void display_lcd(unsigned char *s)
{
while(*s)
write_lcd(*s++);
}
//generates delay in milli seconds
void delay_ms(unsigned int i)
{
unsigned int j;
while(i–>0)
{
for(j=0;j<500;j++)
{
;
}
}
}