DS1307(Real Time clock)

[Dumken]

Good day everyone. Can somone help me out with this part of this code. Am finding it difficult to understand. Also if there is a beta explanation one can give on how the register works and How the clock can work.. i'll appreciate.

Am finding it hard understanding the colored part of the code

// LCD module connections
sbit LCD_RS at RB2_bit;
sbit LCD_EN at RB3_bit;
sbit LCD_D4 at RB4_bit;
sbit LCD_D5 at RB5_bit;
sbit LCD_D6 at RB6_bit;
sbit LCD_D7 at RB7_bit;

sbit LCD_RS_Direction at TRISB2_bit;
sbit LCD_EN_Direction at TRISB3_bit;
sbit LCD_D4_Direction at TRISB4_bit;
sbit LCD_D5_Direction at TRISB5_bit;
sbit LCD_D6_Direction at TRISB6_bit;
sbit LCD_D7_Direction at TRISB7_bit;
// End LCD module connections



unsigned short read_ds1307(unsigned short address)
{
unsigned short r_data;
I2C1_Start();
I2C1_Wr(0xD0); //address 0x68 followed by direction bit (0 for write, 1 for read) 0x68 followed by 0 --> 0xD0
I2C1_Wr(address);
I2C1_Repeated_Start();
I2C1_Wr(0xD1); //0x68 followed by 1 --> 0xD1
r_data=I2C1_Rd(0);
I2C1_Stop();
return(r_data);
}


void write_ds1307(unsigned short address,unsigned short w_data)
{
I2C1_Start(); // issue I2C start signal
//address 0x68 followed by direction bit (0 for write, 1 for read) 0x68 followed by 0 --> 0xD0
I2C1_Wr(0xD0); // send byte via I2C (device address + W)
I2C1_Wr(address); // send byte (address of DS1307 location)
I2C1_Wr(w_data); // send data (data to be written)
I2C1_Stop(); // issue I2C stop signal
}


unsigned char BCD2UpperCh(unsigned char bcd)
{
return ((bcd >> 4) + '0');
}


unsigned char BCD2LowerCh(unsigned char bcd)
{
return ((bcd & 0x0F) + '0');
}


int Binary2BCD(int a)
{
int t1, t2;
t1 = a%10;
t1 = t1 & 0x0F;
a = a/10;
t2 = a%10;
t2 = 0x0F & t2;
t2 = t2 << 4;
t2 = 0xF0 & t2;
t1 = t1 | t2;
return t1;
}


int BCD2Binary(int a)
{
int r,t;
t = a & 0x0F;
r = t;
a = 0xF0 & a;
t = a >> 4;
t = 0x0F & t;
r = t*10 + r;
return r;
}

int second;
int minute;
int hour;
int hr;
int day;
int dday;
int month;
int year;
int ap;

unsigned short set_count = 0;
short set;

char time[] = "00:00:00 PM";
char date[] = "00-00-00";

void main()
{
I2C1_Init(100000); //DS1307 I2C is running at 100KHz

CMCON = 0x07; // To turn off comparators
ADCON1 = 0x06; // To turn off analog to digital converters

TRISA = 0x07;
PORTA = 0x00;

Lcd_Init(); // Initialize LCD
Lcd_Cmd(_LCD_CLEAR); // Clear display
Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off
Lcd_out(1,1,"Time:");
Lcd_out(2,1,"Date:");

do
{
set = 0;
if(PORTA.F0 == 0)
{
Delay_ms(100);
if(PORTA.F0 == 0)
{
set_count++;
if(set_count >= 7)
{
set_count = 0;
}
}
}
if(set_count)
{
if(PORTA.F1 == 0)
{
Delay_ms(100);
if(PORTA.F1 == 0)
set = 1;
}

if(PORTA.F2 == 0)
{
Delay_ms(100);
if(PORTA.F2 == 0)
set = -1;
}
if(set_count && set)
{
switch(set_count)
{
case 1:
hour = BCD2Binary(hour);
hour = hour + set;
hour = Binary2BCD(hour);
if((hour & 0x1F) >= 0x13)
{
hour = hour & 0b11100001;
hour = hour ^ 0x20;
}
else if((hour & 0x1F) <= 0x00)
{
hour = hour | 0b00010010;
hour = hour ^ 0x20;
}
write_ds1307(2, hour); //write hour
break;
case 2:
minute = BCD2Binary(minute);
minute = minute + set;
if(minute >= 60)
minute = 0;
if(minute < 0)
minute = 59;
minute = Binary2BCD(minute);
write_ds1307(1, minute); //write min
break;
case 3:
if(abs(set))
write_ds1307(0,0x00); //Reset second to 0 sec. and start Oscillator
break;
case 4:
day = BCD2Binary(day);
day = day + set;
day = Binary2BCD(day);
if(day >= 0x32)
day = 1;
if(day <= 0)
day = 0x31;
write_ds1307(4, day); // write date 17
break;
case 5:
month = BCD2Binary(month);
month = month + set;
month = Binary2BCD(month);
if(month > 0x12)
month = 1;
if(month <= 0)
month = 0x12;
write_ds1307(5,month); // write month 6 June
break;
case 6:
year = BCD2Binary(year);
year = year + set;
year = Binary2BCD(year);
if(year <= -1)
year = 0x99;
if(year >= 0x50)
year = 0;
write_ds1307(6, year); // write year
break;
}
}
}

second = read_ds1307(0);
minute = read_ds1307(1);
hour = read_ds1307(2);
hr = hour & 0b00011111;
ap = hour & 0b00100000;
dday = read_ds1307(3);
day = read_ds1307(4);
month = read_ds1307(5);
year = read_ds1307(6);


time[0] = BCD2UpperCh(hr);
time[1] = BCD2LowerCh(hr);
time[3] = BCD2UpperCh(minute);
time[4] = BCD2LowerCh(minute);
time[6] = BCD2UpperCh(second);
time[7] = BCD2LowerCh(second);

date[0] = BCD2UpperCh(day);
date[1] = BCD2LowerCh(day);
date[3] = BCD2UpperCh(month);
date[4] = BCD2LowerCh(month);
date[6] = BCD2UpperCh(year);
date[7] = BCD2LowerCh(year);

if(ap)
{
time[9] = 'P';
time[10] = 'M';
}
else
{
time[9] = 'A';
time[10] = 'M';
}


Lcd_out(1, 6, time);
Lcd_out(2, 6, date);
Delay_ms(100);


}while(1);
}

 

[MrAl]

Hi,

Just a quick guess, but it looks like they are converting 24 hour time format to 12 hour format (after a change in hours) because they are comparing the changed hour with the BCD number 0x13 which would read "13 o'clock" which has to be converted to "1 o'clock", or rather 13 hundred hours to 1pm.
They also test for zero o'clock which would have to be changed to 12 midnight.
I didnt go over the code carefully but that's what it looks like. See if you can figure it out from there.
Some routines will keep track of "am" or "pm" too but some wont as they will just display 1hr to 12hr and then back to 1hr without taking note of whether or not it is 'am' or 'pm'.

The most common time formats are:
24 hour format, which goes 0000 to 2359, and
12 hour format, without am/pm, which goes 1200 to 1159, and
12 hour format with am/pm, which goes 1200am to 1159pm.
Minutes rollover is always after 59 minutes.

 

[Ian Rogers]

MrAl Not so sure... It seems to be an hour decrement.. But when it goes negative, it checks the format and either makes

it swing round to 12 or 24...

 

[MrAl]

Hi Ian,

You could be right, i didnt go over it that carefully myself.

 

[koolguy]

Hi Dumken

My code are working do you need it?

 

[Dumken]

Hi Dumken

My code are working do you need it?

Yes Koolguy i'll really appreciate. I need a detailed explanation of a code to learn from. it would be a plus if it is done with 7 segment disp. But anyone u have pls give me

 

[koolguy]

OK, pls give email

 

[Ian Rogers]

Yes Koolguy i'll really appreciate. I need a detailed explanation of a code to learn from. it would be a plus if it is done with 7 segment disp. But anyone u have pls give me

koolguy You do realize that he needs mikroC code??? Also he needs it "well" documented!!

 

[Dumken]

OK, pls give email

chibunduogbonnia@yahoo.com

 

[koolguy]

koolguy You do realize that he needs mikroC code??? Also he needs it "well" documented!!

Ok, i will try the best