Adjustable Clock DS1307

We learned how to read and set DS1307 clock in our previous examples. We will develop an adjustable clock in this example. There are three buttons SET, UP, DOWN as you see on commercial digital clocks. SET button will select and blink  hour and minutes sequentially.  UP,DOWN buttons will increment or decrement hours or minutes.

Proteus: DS1307 with a crystal. LCD is connected to PORTB. RA0, RA1,RA2 are used for setting buttons.

MCC: nothing special. RA0,RA1,RA2 is set for input. select MSSP, I2C master, 1Khz. 1Mhz internal oscillator.

XC8: Enable global and peripheral interrupts. First set clock to 03:02:01 we will not use day, month year but I set them, too. read DS1307 and print to LCD. In case of SET button pressed, set seconds to zero and check UP/DOWN buttons. If up/down buttons are pressed change hour/minutes. Second SET button will switch to minutes and third SET button will set the clock.

I converted DS1307 BCD values to decimal for math operations and turned back to BCD again for register setting.  

    

    unsigned char s1[10], s2[10];

    uint8_t hr[2]={1,0}, readValue[7], writeValue[8]={0,1,2,3,4,5,6,7};

    uint8_t c,ho,mi,se,da,mo,ye;

    I2C_MESSAGE_STATUS    I2C_status;

    

    I2C_MasterWrite( &writeValue, 8, 0b1101000, &I2C_status); //sets pointer address and write data

    while (I2C_MESSAGE_PENDING  == I2C_status ); 

    

    OpenXLCD(FOUR_BIT & LINES_5X7);

    WriteCmdXLCD(DON&CURSOR_OFF&BLINK_OFF); 

    

    while (1)

    {

        // Add your application code

        

    I2C_MasterWrite( 0, 1, 0b1101000, &I2C_status); //set pointer address to zero

    while (I2C_MESSAGE_PENDING  == I2C_status);

    I2C_MasterRead( &readValue, 7, 0b1101000, &I2C_status); // read 7 bytes starting from zero

    while (I2C_MESSAGE_PENDING  == I2C_status );

    sprintf(s1, "%02X:%02X:%02X", readValue[2],readValue[1],readValue[0]);             

        

    SetDDRamAddr(0x01); // clear LCD          

    SetDDRamAddr(0x00); // first line 

    putrsXLCD(s1);        

    SetDDRamAddr(0x40); // goto second line

    putrsXLCD(s2);

    

    writeValue[0]=0;  //pointer address of zero 

    writeValue[1]=readValue[0]; //sec

    writeValue[2]=readValue[1]; //min

    writeValue[3]=readValue[2]; //hour

    writeValue[4]=readValue[3]; //weekday

    writeValue[5]=readValue[4]; //day

    writeValue[6]=readValue[5]; //month

    writeValue[7]=readValue[6]; //year

        

    ho=readValue[2]; mi=readValue[1]; se=readValue[0];

    da=readValue[4]; mo=readValue[5]; ye=readValue[6];

    

    c=0;

    if (IO_RA0_GetValue()==1) { //set pressed

    c=(c+1) % 3;   // set value 0=no-set,1=hour,2=minutes

    

    while (c==1){ //set hours    

        

    writeValue[1]=0; //set seconds to zero

    

    ho=(ho>>4)*10+(ho&0x0F); //bcd2dec

    if (IO_RA1_GetValue()==1) ho=(ho+1) % 24; //up

    if (IO_RA2_GetValue()==1) ho=(ho+23) % 24; //down

    ho=((ho/10)<<4)+(ho%10); //dec2bcd

    writeValue[3]=ho;

    

    sprintf(s1, "%02X:%02X:%02X", ho,mi,0);             

    SetDDRamAddr(0x01); // clear LCD          

    SetDDRamAddr(0x00); // first line 

    putrsXLCD(s1);        

    __delay_ms(100);

    

    sprintf(s1, "  :%02X:%02X",mi,0);             

    SetDDRamAddr(0x01); // clear LCD          

    SetDDRamAddr(0x00); // first line 

    putrsXLCD(s1);        

    __delay_ms(100);

    

    

    if (IO_RA0_GetValue()==1) { //set pressed

        c=(c+1) % 3;

        I2C_MasterWrite( &writeValue, 8, 0b1101000, &I2C_status); //sets pointer address and write data

        while (I2C_MESSAGE_PENDING  == I2C_status ); 

    }

    }

    while (c==2){ //set minutes       

    mi=(mi>>4)*10+(mi&0x0F); //bcd2dec

    if (IO_RA1_GetValue()==1) mi=(mi+1) % 60; //up

    if (IO_RA2_GetValue()==1) mi=(mi+59) % 60; //down

    mi=((mi/10)<<4)+(mi%10); //dec2bcd

    writeValue[2]=mi; 

    

    sprintf(s1, "%02X:%02X:%02X", ho,mi,0);             

    SetDDRamAddr(0x01); // clear LCD          

    SetDDRamAddr(0x00); // first line 

    putrsXLCD(s1);        

    __delay_ms(100);

    

    sprintf(s1, "%02X:  :%02X",ho,0);             

    SetDDRamAddr(0x01); // clear LCD          

    SetDDRamAddr(0x00); // first line 

    putrsXLCD(s1);        

    __delay_ms(100);

    

   if (IO_RA0_GetValue()==1){ 

        c=(c+1) % 3;

        I2C_MasterWrite( &writeValue, 8, 0b1101000, &I2C_status); //sets pointer address and write data

        while (I2C_MESSAGE_PENDING  == I2C_status ); 

    }

    }    

    }

        

        __delay_ms(1000);

    }

    

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