Decimal to Hex Conversion C Code needed

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Yes, they look good. By using dec2bcd(), you don't need to care for the value details, however.
 

internetuser2k12 said:
49 decimal is 0x31, but you said I have to use bcd? bcd of decimal 49 is 49. Should write 0x49 or just 49? Just 49 means decimal 49, 0x49 means bcd 49.
Click to expand...

Unfortunately you still seem to have a blurry understanding of BCD , I have no other way to explain why you wrote that.
Go back in this thread and take some time to read all the explanations provided about BCD.
 

@ FvM

when I simulated in proteus I actually had to give decimal values 0..15, 22..31, 38..43 for day 0..31 otherwise it is giving wrong values.

- - - Updated - - -

@ alexan_e

OK. alexan_e. I will take your advice.

It's all because of proteus I got confused.
 

when I simulated in proteus I actually had to give decimal values 0..15, 22..31, 38..43 for day 0..31 otherwise it is giving wrong values.
Click to expand...
Makes no sense at all.
 

@ FvM. OK. I finished my project. Every thing is working fine. Please check it once. I have attached my project files. I have used decimal values to write to DS1307.
The alarm is also working. Just a small problem. It might be a problem of proteus. I use values 0 - 153 (Decimal) i.e., 0-99 (BCD) to write to year register of DS1307, but in the Proteus clock windows when the BCD value is 70 i.e., decimal 112, it shows some wrong values in the proteus clock window.

One more thing I want to know is if I write decimal 153 to year register of DS1307 will it take it as BCD 99? I also want to know how to represent decimal numbers > 99 in BCD.

Here is what I do. Decimal 153 = (hex) 0x99, BCD = 1001 1001. or writing decimal 99 as 0x99 (hex) and converting it to decimal gives 153.

Here is the code

Code: 
#ifndef DS1307
        #define DS1307 0xD0
#endif

#define SET RA0_bit
#define INC RA1_bit
#define DEC RA2_bit
#define OK RA3_bit

// 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 char num, flag, set_time_flag;
char b, x, i, sec, min1, hr, week_day, day, mn, year;
char *txt, tnum[4], time_format[3], sihr[17];
char colon[] = ":";
int cnt, ihr, error, am_pm = 0;
bit set_flag, inc_flag, dec_flag, ok_flag, do_once_hr, do_once_min, do_once_sec, do_once_day, do_once_mn, do_once_year;
bit dec_do_once_hr, dec_do_once_min, dec_do_once_sec, dec_do_once_day, dec_do_once_mn, dec_do_once_year;
bit inc_do_once_hr, inc_do_once_min, inc_do_once_sec, inc_do_once_day, inc_do_once_mn, inc_do_once_year;
bit alarm_flag, alarm_set_flag;
unsigned char set_cnt, inc_cnt, dec_cnt = 0;
unsigned char ssec, smin, shr, sweek_day, sday, smn, syear;
unsigned char s_sec, s_min, s_hr, s_week_day, s_day, s_mn, s_year;
unsigned char asec, amin, ahr, aweek_day, aday, amn, ayear;


void Zero_Fill(char *value) {
        if (value[1] == 0) {
                value[1] = value[0];
                value[0] = 48;
                value[2] = 0;
        }
}

void Write_Time() {
        I2C1_Start();          // issue start signal
        I2C1_Wr(DS1307);       // address DS1307
        I2C1_Wr(0);            // start from word at address (REG0)
        I2C1_Wr(0x80);         // write $80 to REG0. (pause counter + 0 sec)
        I2C1_Wr(s_min);         // write 11 to minutes word to (REG1)
        I2C1_Wr(s_hr);          // write 17 to hours word (24-hours mode)(REG2)
        I2C1_Wr(s_week_day);    // write 6 - Friday (REG3)
        I2C1_Wr(s_day);         // write 23 to date word (REG4)
        I2C1_Wr(s_mn);          // write 11 (Nov) to month word (REG5)
        I2C1_Wr(s_year);        // write 12 to year word (REG6)
        I2C1_Stop();           // issue stop signal

        I2C1_Start();          // issue start signal
        I2C1_Wr(DS1307);       // address DS1307
        I2C1_Wr(0);            // start from word at address 0
        I2C1_Wr(0);            // write 0 to REG0 (enable counting + 0 sec)
        I2C1_Stop();           // issue stop signal
}

void Read_Time(char *sec, char *min, char *hr, char *week_day, char *day, char *mn, char *year) {
        I2C1_Start();
        I2C1_Wr(DS1307);
        I2C1_Wr(0);
        I2C1_Repeated_Start();
        I2C1_Wr(0xD1);
        *sec = I2C1_Rd(1);
        *min = I2C1_Rd(1);
        *hr = I2C1_Rd(1);
        *week_day = I2C1_Rd(1);
        *day = I2C1_Rd(1);
        *mn = I2C1_Rd(1);
        *year = I2C1_Rd(0);
        I2C1_Stop();

        I2C1_Start();
        I2C1_Wr(DS1307);
        I2C1_Wr(0);
        I2C1_Repeated_Start();
        I2C1_Wr(0xD1);
        s_sec = I2C1_Rd(1);
        s_min = I2C1_Rd(1);
        s_hr = I2C1_Rd(1);
        s_week_day = I2C1_Rd(1);
        s_day = I2C1_Rd(1);
        s_mn = I2C1_Rd(1);
        s_year =I2C1_Rd(0);
        I2C1_Stop();


}

void Transform_Time(char  *sec, char *min, char *hr, char *week_day, char *day, char *mn, char *year) {
        *sec  =  ((*sec & 0x70) >> 4)*10 + (*sec & 0x0F);
        *min  =  ((*min & 0xF0) >> 4)*10 + (*min & 0x0F);
        *hr   =  ((*hr & 0x30) >> 4)*10 + (*hr & 0x0F);
        *week_day =(*week_day & 0x07);
        *day  =  ((*day & 0xF0) >> 4)*10 + (*day & 0x0F);
        *mn   =  ((*mn & 0x10) >> 4)*10 + (*mn & 0x0F);
        *year =  ((*year & 0xF0)>>4)*10+(*year & 0x0F);
        
        /*
        ssec  =  ((*sec & 0x70) >> 4)*10 + (*sec & 0x0F);
        smin  =  ((*min & 0xF0) >> 4)*10 + (*min & 0x0F);
        shr   =  ((*hr & 0x30) >> 4)*10 + (*hr & 0x0F);
        sweek_day =(*week_day & 0x07);
        sday  =  ((*day & 0xF0) >> 4)*10 + (*day & 0x0F);
        smn   =  ((*mn & 0x10) >> 4)*10 + (*mn & 0x0F);
        syear =  ((*year & 0xF0)>>4)*10+(*year & 0x0F);
        */


}

void Display_Time(char sec, char min, char hr, char week_day, char day, char mn, char year) {
        if(alarm_flag == 0) {
        switch(week_day){
                case 1: txt="Sun"; break;
                case 2: txt="Mon"; break;
                case 3: txt="Tue"; break;
                case 4: txt="Wed"; break;
                case 5: txt="Thu"; break;
                case 6: txt="Fri"; break;
                case 7: txt="Sat"; break;
        }
        Lcd_Out(1,1,txt);
        Lcd_Chr(1,5,(day / 10)   + 48);    // Print tens digit of day variable
        Lcd_Chr(1,6, (day % 10)   + 48);    // Print oness digit of day variable
        Lcd_Chr(1,7,'/');
        Lcd_Chr(1,8,(mn / 10) + 48);
        Lcd_Chr(1,9,(mn % 10) + 48);
        Lcd_Chr(1,10,'/');
        Lcd_Out(1,11,"2");
        Lcd_Out(1,12,"0");
        Lcd_Chr(1,13, (year / 10)  + 48);          // Print year vaiable + 8 (start from year 2008)
        Lcd_Chr(1,14, (year % 10)  + 48);

        /*
        if(hr >= 12) {
           Lcd_Out(2,2,"PM");
           am_pm = 1;
        }
        else if(hr < 12) {
           Lcd_Out(2,2,"AM");
           am_pm = 0;
        }
        */

        Lcd_Chr(2,5,(hr / 10)  + 48);
        Lcd_Chr(2,6,(hr % 10)  + 48);
        Lcd_Out(2,7,":");
        Lcd_Chr(2,8,(min / 10) + 48);
        Lcd_Chr(2,9,(min % 10) + 48);
        Lcd_Out(2,10,":");
        Lcd_Chr(2,11,(sec / 10) + 48);
        Lcd_Chr(2,12,(sec % 10) + 48);
        }
}

void Display_Alarm_Time(char asec, char amin, char ahr, char aweek_day, char aday, char amn, char ayear) {
        if(alarm_flag == 1) {
              Lcd_Out(1,1,"ALR");
              Lcd_Chr(1,5,(aday / 10)   + 48);    // Print tens digit of day variable
              Lcd_Chr(1,6, (aday % 10)   + 48);    // Print oness digit of day variable
              Lcd_Chr(1,7,'/');
              Lcd_Chr(1,8,(amn / 10) + 48);
              Lcd_Chr(1,9,(amn % 10) + 48);
              Lcd_Chr(1,10,'/');
              Lcd_Out(1,11,"2");
              Lcd_Out(1,12,"0");
              Lcd_Chr(1,13, (ayear / 10)  + 48);          // Print year vaiable + 8 (start from year 2008)
              Lcd_Chr(1,14, (ayear % 10)  + 48);
              Lcd_Chr(2,5,(ahr / 10)  + 48);
              Lcd_Chr(2,6,(ahr % 10)  + 48);
              Lcd_Out(2,7,":");
              Lcd_Chr(2,8,(amin / 10) + 48);
              Lcd_Chr(2,9,(amin % 10) + 48);
              Lcd_Out(2,10,":");
              Lcd_Chr(2,11,(asec / 10) + 48);
              Lcd_Chr(2,12,(asec % 10) + 48);
        }
}


void main() {

     TRISA = 0b00001111;
     PORTA = 0b00000000;
     TRISB = 0b00000000;
     PORTB = 0b00000000;
     ADCON0 = 0b00000000;
     ADCON1 = 0b10000111;

     Lcd_Init();
     Lcd_Cmd(_LCD_CLEAR);
     Lcd_Cmd(_LCD_CURSOR_OFF);
     Lcd_Out(1,4,"RTC DS1307");
     Delay_ms(3000);
     I2C1_Init(100000);
     Lcd_Cmd(_LCD_CLEAR);

     set_time_flag = 0;
     ok_flag = 1;
     alarm_flag = 0;
     alarm_set_flag = 0;

     ssec = 0x00;
     smin = 0x00;
     shr = 0x00;
     sweek_day = 0x01;
     sday = 0x00;
     smn = 0x00;
     syear = 0x00;
     asec = 0x00;
     amin = 0x00;
     ahr = 0x00;
     aday = 0x00;
     amn = 0x00;
     ayear = 0x00;

     while(1) {
     
         if((SET == 1) && (INC == 0) && (DEC == 0) &&(OK == 0)) {
               Delay_ms(100);
               if((SET == 1) && (INC == 0) && (DEC == 0) && (OK == 0)) {
                       set_flag = 1;
                       set_time_flag = 1;
                       set_cnt++;
                       if(set_cnt > 11) {
                                  set_cnt = 1;
                                  alarm_flag = 0;
                       }
                       else if(set_cnt == 7) alarm_flag = 1;
               }
         }
         else if((INC == 1) && (DEC == 0) && (SET == 0) && (OK == 0) && (set_flag == 1)) {
                    Delay_ms(100);
                    if((INC == 1) && (DEC == 0) && (SET == 0) && (OK == 0) && (set_flag == 1)) {
                            inc_flag = 1;
                            if(alarm_flag == 0) {
                            switch(set_cnt) {
                               case 1:
                                    sweek_day++;
                                    if(sweek_day > 7) sweek_day = 1;
                                    break;
                               case 2:
                                    sday++;
                                    if(sday == 10) sday = 16;
                                    if(sday == 26) sday = 32;
                                    if(sday == 42) sday = 48;
                                    if(sday > 49) sday  = 1;
                                    break;
                               case 3:
                                    smn++;
                                    if(smn == 9) smn = 16;
                                    if(smn > 18) smn = 1;
                                    break;
                               case 4:
                                    syear++;
                                    if(syear == 10) syear = 16;
                                    if(syear == 26) syear = 32;
                                    if(syear == 42) syear = 48;
                                    if(syear == 58) syear = 64;
                                    if(syear == 74) syear = 80;
                                    if(syear == 90) syear = 96;
                                    if(syear == 106) syear == 112;
                                    if(syear == 122) syear = 128;
                                    if(syear == 138) syear = 144;
                                    if(syear > 153) syear = 0;
                                    break;
                               case 5:
                                    shr++;
                                    if(shr == 10) shr = 16;
                                    if(shr == 26) shr = 32;
                                    if(shr > 35) shr = 0;
                                    break;
                               case 6:
                                    smin++;
                                    if(smin == 10) smin = 16;
                                    if(smin == 26) smin = 32;
                                    if(smin == 42) smin = 48;
                                    if(smin == 58) smin = 64;
                                    if(smin == 74) smin = 80;
                                    if(smin > 89) smin = 0;
                                    break;
                               default:
                                     break;

                            };
                            }

                            else if(alarm_flag == 1) {
                                  switch(set_cnt) {
                               case 7:
                                    aday++;
                                    if(aday > 31) aday = 1;
                                    break;;
                               case 8:
                                    amn++;
                                    if(amn > 12) amn = 1;
                                    break;
                               case 9:
                                    ayear++;
                                    if(ayear > 99) ayear = 0;
                                    break;
                               case 10:
                                    ahr++;
                                    if(ahr > 23) ahr = 0;
                                    break;
                               case 11:
                                    amin++;
                                    if(amin > 59) amin = 0;
                                    break;
                               default:
                                     break;
                            };
                            }
                    }
         }
         else if((DEC == 1) && (SET == 0) && (INC == 0) && (OK == 0) && (set_flag == 1)) {
                    Delay_ms(100);
                    if((DEC == 1) && (SET == 0) && (INC == 0) && (OK == 0) && (set_flag == 1)) {
                            dec_flag = 1;
                            if(alarm_flag == 0) {
                            switch(set_cnt) {
                               case 1:
                                    sweek_day--;
                                    if(sweek_day < 1) sweek_day = 7;
                                    break;
                               case 2:
                                    sday--;
                                    if(sday == 15) sday = 9;
                                    if(sday == 33) sday = 25;
                                    if(sday == 47) sday = 41;
                                    if(sday > 49) sday  = 49;
                                    break;
                               case 3:
                                    smn--;
                                    if(smn == 9) smn = 16;
                                    if(smn > 18) smn = 18;
                                    break;
                               case 4:
                                    syear--;
                                    if(syear == 15) syear = 9;
                                    if(syear == 33) syear = 25;
                                    if(syear == 47) syear = 41;
                                    if(syear == 63) syear = 57;
                                    if(syear == 79) syear = 73;
                                    if(syear == 95) syear = 89;
                                    if(syear == 111) syear == 105;
                                    if(syear == 127) syear = 121;
                                    if(syear == 143) syear = 137;
                                    if(syear > 153) syear = 153;
                                    break;
                               case 5:
                                    shr--;
                                    if(shr == 15) shr = 9;
                                    if(shr == 33) shr = 25;
                                    if(shr > 35) shr = 35;
                                    break;
                               case 6:
                                    smin--;
                                    if(smin == 15) smin = 9;
                                    if(smin == 33) smin = 25;
                                    if(smin == 47) smin = 41;
                                    if(smin == 63) smin = 57;
                                    if(smin == 79) smin = 73;
                                    if(smin > 89) smin = 89;
                                    break;
                               default:
                                     break;

                            };
                            }
                            else if(alarm_flag == 1) {
                                 switch(set_cnt) {
                                  case 7:
                                    aday--;
                                    if(aday > 31) aday = 31;
                                    if(aday < 1) aday = 31;
                                    break;
                               case 8:
                                    amn--;
                                    if(amn > 12) amn = 12;
                                    if(amn < 1) amn = 12;
                                    break;
                               case 9:
                                    ayear--;
                                    if(ayear > 99) ayear = 99;
                                    if(ayear < 0) ayear = 99;
                                    break;
                               case 10:
                                    ahr--;
                                    if(ahr > 23) ahr = 23;
                                    if(ahr < 0) ahr = 23;
                                    break;
                               case 11:
                                    amin--;
                                    if(amin > 59) amin = 59;
                                    if(amin < 0) amin = 59;
                                    break;
                               default:
                                     break;
                            };
                            }
                    }
         }
         else if((OK == 1) && (SET == 0) && (INC == 0) && (DEC == 0) && (set_flag == 1)) {
              Delay_ms(100);
              if((OK == 1) && (SET == 0) && (INC == 0) && (DEC == 0) && (set_flag == 1)) {
              set_flag = 0;
              set_time_flag = 0;
              ok_flag = 1;
              alarm_flag = 0;
              alarm_set_flag = 1;
              set_cnt = 0;
              inc_flag = 0;
              dec_flag = 0;
              }
         }
         
         if((inc_flag == 1) || (dec_flag == 1)) {

                s_sec =  ssec;
                s_min = smin;
                s_hr = shr;
                s_week_day = sweek_day;
                s_day = sday;
                s_mn = smn;
                s_year = syear;
                
                /*
                ssec = s_sec;
                smin = s_min;
                shr = s_hr;
                sweek_day = s_week_day;
                sday = s_day;
                smn = s_mn;
                syear = s_year;
                */
                
                /*
                s_sec = Dec2Bcd(ssec);
                s_min = Dec2Bcd(smin);
                s_hr = Dec2Bcd(shr);
                s_week_day = Dec2Bcd(sweek_day);
                s_day = Dec2Bcd(sday);
                s_mn = Dec2Bcd(smn);
                s_year = Dec2Bcd(syear);
                */
         }
         
         //Read_Time(&sec,&min1,&hr,&week_day,&day,&mn,&year);
         
         if(set_time_flag == 1) {
                Write_Time();
                Read_Time(&sec,&min1,&hr,&week_day,&day,&mn,&year);
                ok_flag = 0;
         }
         
         if(ok_flag == 1) {
                Read_Time(&sec,&min1,&hr,&week_day,&day,&mn,&year);
         }
         
         if(alarm_flag == 0) {
                 Transform_Time(&sec,&min1,&hr,&week_day,&day,&mn,&year);
                 Display_Time(sec, min1, hr, week_day, day, mn, year);
                 if(alarm_set_flag == 1) {
                          //if((day == aday) && (mn == amn) && (year == ayear) && (hr == ahr) && (min1 == amin)) {
                                 //PORTB.F0 = 1;
                          //}
                          if((day == aday) && (mn = amn) && (year == ayear) && (hr == ahr) && (min1 == amin)) {
                                 PORTB.F0 = 1;
                          }
                 }
         }

         if(alarm_flag == 1) {
                Display_Alarm_Time(asec, amin, ahr, aweek_day, aday, amn, ayear);
         }

     }
}

OK. Ifound out the problem. Actually the value in Proteus clock window was giving the following values for year 70 to 75 and after displaying 75 it was again starting the count from 70 and go upto 99 and cycle.

The problem is shown in the below code. The problem is highlighted.

Code: 
                                    if(syear == 10) syear = 16;
                                    if(syear == 26) syear = 32;
                                    if(syear == 42) syear = 48;
                                    if(syear == 58) syear = 64;
                                    if(syear == 74) syear = 80;
                                    if(syear == 90) syear = 96;
                                    if(syear == 106) syear [B] [COLOR="#0000FF"]==[/COLOR] [/B] 112;
                                    if(syear == 122) syear = 128;
                                    if(syear == 138) syear = 144;
                                    if(syear > 153) syear = 0;

This line was causing the problem if(syear == 106) syear == 112; .

After fixing it, it is working fine. There was no problem with Proteus.
 

Attachments

  • PIC16F877 DS1307 RTC v30.rar
    106 KB · Views: 103
Last edited:

I don't see a problem in the code that explains problems with year 70. Seems like a case for regular debugging, inspect the data sent to the RTC chip.

RTC registers have 8-bit size, they represent decimal numbers with two digits. 99 is the largest number that can be represented in 8-bit BCD.
 

@ FvM

See I have attached the image showing error. from year 2070 to 2099 I get some random values in Proteus Clock Windows.



The error was because of the below statement

Code: 
 if(syear == 106) syear == 112;
Now it is fixed.

Problem was also in
Code: 
 if(syear == 111) syear == 105;
 

Attachments

  • rtc ds1307 error.jpg
    88.8 KB · Views: 104
Last edited:

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