Rtc
#define DS1307_ID 0xD0
#define SEC 0x00
#define MIN 0x01
#define HOUR 0x02
#define DATE 0x04
#define MONTH 0x05
#define YEAR 0x06
sbit sda_rtc =P2^0;
sbit scl_rtc =P2^1;
DS1307_get(unsigned char);
void DS1307_settime(unsigned char, unsigned char, unsigned char);
void DS1307_setdate(unsigned char, unsigned char, unsigned char);
Send2lcd(unsigned char);
void Rtc_Write(unsigned char,unsigned char);
Rtc_Read(unsigned char);
void Rtc_rd_wr_sub();
void Rtc_Init();
void Rtc_Start();
void Rtc_Tx();
void Rtc_Rx();
void Rtc_Stop();
void Rtc_Ack();
unsigned int Rtc_add_wr,Rtc_add_rd;
unsigned char d_rtc,datain_rtc,in_rtc,temp_rtc,dat_rtc,flag_rtc;
DS1307_get(unsigned char addr)
{
unsigned char ret;
Rtc_Start();
ret = Rtc_Read(addr);
Rtc_Stop();
return ret;
}
void DS1307_settime(unsigned char hh, unsigned char mm, unsigned char ss)
{
Rtc_Start();
Rtc_Write(0x00,ss); /* Write sec on RAM address 00H */
Rtc_Write(0x01,mm); /* Write min on RAM address 01H */
Rtc_Write(0x02,hh); /* Write hour on RAM address 02H */
Rtc_Stop(); /* Stop i2c bus */
}
void DS1307_setdate(unsigned char dd, unsigned char mm, unsigned char yy)
{
Rtc_Start();
Rtc_Write(0x04,dd); /* Write date on RAM address 04H */
Rtc_Write(0x05,mm); /* Write month on RAM address 05H */
Rtc_Write(0x06,yy); /* Write year on RAM address 06H */
Rtc_Stop(); /* Stop i2c bus */
}
Send2lcd(unsigned char value)
{
unsigned char buf1,buf2,buf = 0;
buf1 = value & 0xF0; /* Filter for high byte */
buf1 = (buf1>>4); /* Convert to ascii code */
buf2 = value & 0x0F; /* Filter for low byte */
buf=(buf1*10)+buf2;
return buf;
}
void Rtc_Init()//lower order 256 bytes of the chip
{
Rtc_add_wr=0xd0;
Rtc_add_rd=0xd1;
}
void Rtc_Write(unsigned char zig,unsigned char zag)// program to write to EEPROM
{
dat_rtc=zig;
temp_rtc=zag;
Rtc_rd_wr_sub();
above:
d_rtc=temp_rtc;
Rtc_Tx();
if (CY==1)goto above;
CY=0;
Rtc_Stop();
}
Rtc_Read(unsigned char zig)// program to read from EEPROM
{
dat_rtc=zig;
Rtc_rd_wr_sub();
Rtc_Start();
be:
d_rtc=Rtc_add_rd;
Rtc_Tx();
if(CY==1)goto be;
Rtc_Rx();
Rtc_Ack();
CY=0;
Rtc_Stop();
return(datain_rtc);
}
void Rtc_Start()// must for any operation on EEPROM
{
sda_rtc=1;
scl_rtc=1;
sda_rtc=0;
scl_rtc=0;
}
void Rtc_Stop()// this is similar to the START operation whereas this should be performed after the completion of any operation
{
sda_rtc=0;
scl_rtc=1;
sda_rtc=1;
}
void Rtc_Tx()// program to send the device address, read/write address,data to be written
{
signed char i_rtc;
for(i_rtc=7;i_rtc>=0;i_rtc--)// should necessarily be initialised as signed char.
{
CY=(d_rtc>>i_rtc)&0x01;
sda_rtc=CY;
scl_rtc=1;// clock is essential inorder to write or read
scl_rtc=0;// clk should be alternated
}
sda_rtc=1;
scl_rtc=1;
CY=sda_rtc;
scl_rtc=0;
}
void Rtc_Rx()// program read the data from the EEPROM
{
unsigned char l_rtc;
sda_rtc=1;
for (l_rtc=0;l_rtc<=7;l_rtc++)
{
scl_rtc=1;
in_rtc=in_rtc<<1;
in_rtc|=sda_rtc;
scl_rtc=0;
}
datain_rtc=in_rtc;
in_rtc=0;
}
void Rtc_Ack()// this is to intimate the EEPROM that the read operation is over
{
sda_rtc=1;
scl_rtc=1;
scl_rtc=0;
}
void Rtc_rd_wr_sub()// this routine will be used by both the read & write operations to send the device address & the address at which the corresponding action is to be taken
{
Rtc_Start();
here1:
d_rtc=Rtc_add_wr;// device address is passed
Rtc_Tx();
if(CY==1)goto here1;
again1:
d_rtc=dat_rtc;// the address from which data is to be read/written is to be passed
Rtc_Tx();
if(CY==1)goto again1;
}