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DCF77 decoder

 
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inservi



Joined: 13 May 2007
Posts: 127

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DCF77 decoder
PostPosted: Sun Oct 07, 2007 10:55 am     Reply with quote

Hello, here is a simple DCF77 decoder with little sample.

-----------------------------------------------------------------------
UPDATE The October 08 2007 changing :
#define DCF77ValuesDayOfWeek 5 // ( 3 was a fault )
-----------------------------------------------------------------------
the October 12 2007
some little enhancement in DCF77Decoding.c
-----------------------------------------------------------------------
the October 14 2007
little correction in weekday
-----------------------------------------------------------------------
the October 18 2007
Improvement to the timer management.
Simple sample for how to make a zero drift timer with just some defines
and one set_Timer () at the start of interrupt.

1 - setup the timer for a time overflow a few bigger than the needed one
2 - type the parameters in the #defines as in this sample
3 - add the 'set_TimerX( DCF77SetTimer ); ' at the beginning of the interrupt

-----------------------------------------------------------------------
the june 19 2008
improvement for zero drift timer from ckielstra
-----------------------------------------------------------------------

Code:
////////////////////////////////////////////////////////////////////////////
//               DCF77 DECODER                                            //
//                                                                        //
//  Writen by Daniel ROBERT  V1.0    07 october 2007                      //
//                                                                        //
//                                                                        //
//  Although the radio transmission of DCF77 signal is not                //
//  highly reliable, it can be practical to use it for time               //
//  initialisation.                                                       //
//  It is appropriate then to manage the real houre progression           //
//  with an autonomous clock.                                             //
//                                                                        //
//  If receiver DCF77 is used to maintain the hour  continually,          //
//  it is necessary to check at each end of cycle ( each minute )         //
//  if the new hour is well corresponding to the previous one plus        //
//  one minute. In any way an autonomous (internal) clock is needed       //
//  to allows to maintain the hour right for several minute because       //
//  of some parasite can easily block the reception for a long time.      //
//                                                                        //
//  In some environments, it is difficult to get a right signal           //
//                                                                        //
//  Three led are used for monitoring the reception progress.             //
//    LED_Error  is lighting when radio error                             //
//    LED_ZERO   is flashing when a zero is received                      //
//    LED_ONE    is flashing when a ONE is received                       //
//                                                                        //
//    LED_ZERO and LED_ONE   are lighting together (1 sec) at             //
//                           the start of cycle                           //
//                                                                        //
//  For demo, the result is sended to hyperterminal in VT100 mode         //
//                                                                        //
//  At starting, nothink appens until the 'start' is received (that       //
//  can take almost one minute) Then the two data led are blinking        //
//  togther 1 seconde. After that, the led ONE and ZERO must blink        //
//  one at the time, until the end of cycle. In case of radio error,      //
//  the Error led start lighting until the next start. Then the cycle     //
//  is restarting.                                                        //
//                                                                        //
//  This code will easily work on most PIC with CCS C V 3.x and V 4.x     //
//                                                                        //
//  I'm working to changing 'int DCF77Bits[59]' array for use only        //
//  59 bits rather than 59 bytes.                                         //
//                                                                        //
////////////////////////////////////////////////////////////////////////////

#include "18F2620.h"

#FUSES NOWDT                   //No Watch Dog Timer
#FUSES WDT128                  //Watch Dog Timer uses 1:128 Postscale
#FUSES HS                      //High speed Osc (> 4mhz)
#FUSES NOPROTECT               //Code not protected from reading
#FUSES IESO                    //Internal External Switch Over mode enabled
#FUSES BROWNOUT                //Reset when brownout detected
#FUSES BORV21                  //Brownout reset at 2.1V
#FUSES PUT                     //Power Up Timer
#FUSES NOCPD                   //No EE protection
#FUSES STVREN                  //Stack full/underflow will cause reset
#FUSES NODEBUG                 //No Debug mode for ICD
#FUSES NOLVP                   //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOWRT                   //Program memory not write protected
#FUSES NOWRTD                  //Data EEPROM not write protected
#FUSES NOEBTR                  //Memory not protected from table reads
#FUSES NOCPB                   //No Boot Block code protection
#FUSES NOEBTRB                 //Boot block not protected from table reads
#FUSES NOWRTC                  //configuration not registers write protected
#FUSES NOWRTB                  //Boot block not write protected
#FUSES FCMEN                   //Fail-safe clock monitor enabled
//#FUSES XINST                   //Extended set extension and Indexed Addressing mode enabled
#FUSES NOPBADEN                //PORTB pins are configured as digital I/O on RESET
#FUSES LPT1OSC                 //Timer1 configured for low-power operation
#FUSES MCLR                    //Master Clear pin enabled

//------------------- FOR EASY ZERO DRIFT TIMER -------------------
#define FOSC                 20000000   // used for setup delay and calculate the zero drift timmer
#define DCF77TimerDepth      65536      // for 16 bit timer
#define DCF77TimerPrescaler  1          // for prescaler div by 1
//------------------- FOR EASY ZERO DRIFT TIMER -------------------
 
#use delay(clock=FOSC)


#define LCD_TX     PIN_C6
#define LCD_RX     PIN_C6
#define LCD_BAUD   4800

#define RADIO_PORT     PIN_C2   // input from DCF77 receiver
#define LED_Error      PIN_A2   // led indicating DCF77 error
#define LED_ZERO       PIN_A3   // led indicating a zero from DCF77
#define LED_ONE        PIN_A4   // led indicating a one from DCF77

#define RADIO_PORT_HIGH  input(RADIO_PORT)
#define RADIO_PORT_LOW  !input(RADIO_PORT)

#use RS232(baud=LCD_BAUD, xmit=LCD_TX , rcv=LCD_RX )

#define VT100LF      "%c[B", 27   // "%c%c",13,10
#define VT100CLS     "%c[2J", 27  //"%c",12
#define VT100HOME    "%c[H", 27

// --RTC--
#define RadioLength0         10    // not used - length of pulse for a zero
#define RadioLength1         15    // 150 ms minimum (normalement 160 minimum 200 tipicaly)
#define RadioLengthStart     100   // normaly, 1 sec then 100

#define RadioStartMinute     21    // position of first bit of minute in dcf77 scheme
#define RadioParityMinute    28    // same story for next element
#define RadioStartHeure      29    //    "
#define RadioParityHeure     35    //    "
#define RadioStartDay        36    //    "
#define RadioStartDayOfWeek  42    //    "
#define RadioStartMonth      45    //    "
#define RadioStartYear       50    //    "
#define RadioParity3         58    //    "

#define DCF77ValuesMinute     0    // element number is scheme
#define DCF77ValuesHour       2    // same story for next element
#define DCF77ValuesDay        4    //    "
#define DCF77ValuesDayOfWeek  5    //    "
#define DCF77ValuesMonth      6    //    "
#define DCF77ValuesYear       7    //    "

//------------------- FOR EASY ZERO DRIFT TIMER -------------------
#define DCF77InteruptTime    0.01   // sec
#define DCF77SetTimer        (int16)( DCF77TimerDepth * DCF77TimerPrescaler ) - (int16)( DCF77InteruptTime * (FOSC / 4) )
//------------------- FOR EASY ZERO DRIFT TIMER -------------------


// --------- GLOBAL DECLARATION --------------
int8       DCF77Bits[59] = {0} ;   // table for put all DCF77 bits for one cycle
int8 const DCF77BitWeight[8] = {1,2,4,8,10,20,40,80};
char const DOW[7][8] = { {"Mon\0"}, {"Tues\0"}, {"Wednes\0"}, {"Thurs\0"}, {"Fri\0"}, {"Satur\0"}, {"Sun\0"} } ;

                           // | 128 for set the bit 7  for indicate that it is a parity bit
int8 const DCF77Scheme[9]= { RadioStartMinute, RadioParityMinute | 128, RadioStartHeure, RadioParityHeure | 128,
                             RadioStartDay, RadioStartDayOfWeek, RadioStartMonth, RadioStartYear, RadioParity3 | 128 } ;                       
int8       DCF77Values[9] = {0} ;
int8       DCF77Sec ;
int8       DCF77LastDate = 0 ;
short      DCF77TimeOk = false, DCF77CycleOK = false ;
int8       LastRadioTime = 0 ;
int8       DCF77Pulse = 0 ;                // lenght of pulse is hundredth (sec/100) of Sec
short      RadioBit , RadioParity ;
int8       DCF77BitNbr = 0 ;
short      RadioWaitStart = true, RadioWaitHight, RadioHightMesure ;
int8       heure = 0, Minute = 0, Seconde = 0 ;
int8       day = 0, dayOfWeek = 0, month = 0, year = 0 ;
int8       Sec100 ;
short      SecondeFlag = 0, MinuteFlag = 0 ;
short      RadioError = false ;


#int_timer0
void timer0_isr() {
//------------------- FOR EASY ZERO DRIFT TIMER -------------------
  //set_Timer0( DCF77SetTimer );
  set_timer0( get_timer0() + DCF77SetTimer ) // enhancement from ckielstra
//------------------- FOR EASY ZERO DRIFT TIMER -------------------

  // -- autonomous clock --
  if (++Sec100 == 100) {
    Sec100 = 0 ;
    SecondeFlag = 1 ;
   
    if (++DCF77Sec == 60) DCF77Sec = 0 ; // count hundredth (1/100) of second  for DCF77
   
    if (++Seconde == 60) {            // hours
      Seconde = 0;
      MinuteFlag = 1;
      if (++Minute == 60) {           // hours
        Minute = 0 ;
        if (++heure == 24) heure = 0 ; // days
      }
    }
  }
  // --------------------
 
  if (++DCF77Pulse >= RadioLengthStart) {   //if low for at least 1 sec then start or error. Assume start
    RadioWaitStart = true ;
    RadioWaitHight = false ;
    RadioHightMesure = false ;
  }

  if (RadioWaitStart) { // wait for starting cycle. the length is at least 1 second
    if ( RADIO_PORT_HIGH ) {
      DCF77Pulse = 0 ; // reset if in high pulse ( after an error ) for mesure from start of zero     
    }
    if (DCF77Pulse >= RadioLengthStart) { // starting cycle
      RadioError = false ;
      output_high(LED_ZERO);   //
      output_high(LED_ONE);    // At start, the two led (one and zero) are blinking together
      DCF77Pulse =0 ;          // reset hundredth count
      RadioWaitStart = false ;
      RadioWaitHight = true ;  // past to next step wait for begin of hight pulse
      DCF77BitNbr = 0 ;
      DCF77Sec = 59 ;          // init secondes
      Sec100 = 30 ;

    }
  }

  if (RadioWaitHight) { // wait for start of hight pulse
    if ( RADIO_PORT_HIGH ) {
      DCF77Pulse = 0 ;
      RadioWaitHight = false ;
      RadioHightMesure = true ;
      output_low(LED_ZERO);
      output_low(LED_ONE);
    }
  }

  if (RadioHightMesure) {   // mesure the lengh of higth pulse
    if ( RADIO_PORT_LOW ) { // end of high pulse, now DCF77Pulse contain the length of high pulse
      RadioBit = (DCF77Pulse >= RadioLength1) ;   // if DCF77 high pulse is greater than 160mS is 1 else is 0
      if ( DCF77Pulse > 25 || DCF77Pulse < 8 ) {  // if DCF77 high pulse is greater than 210mS or smaller 90mS then error
        RadioError = true ;
        RadioWaitStart = true ;                   // restart the waiting for start pulse (no signal for 1 sec)
      }
     
      DCF77Pulse = 0 ;                            // reset counter for pulse length
      DCF77Bits[DCF77BitNbr] = RadioBit ;         // put bit into table

      if (++DCF77BitNbr == 59) {                  // if end of cycle
        RadioWaitStart = true ;
        DCF77CycleOK = true ;
      }
      RadioHightMesure = false ;
      RadioWaitHight = !RadioWaitStart  ;         // back to wait for next hight pulse if cycle not finished and no error
     
      // --- can be deleted --- juste for debugging
      output_bit(LED_ZERO, !RadioBit ) ;         
      output_bit(LED_ONE,   RadioBit ) ;
      // ----------------------

    }
  }
}

#include <calcDCF77.c>


void StartTimer() {
  Sec100 = 0 ;
  set_Timer0( DCF77SetTimer );
  enable_interrupts(INT_TIMER0);
}

void StopTimer() {
  DISABLE_INTERRUPTS(INT_TIMER0);
}

int DCF77DateInt() { 
  return(DCF77Values[DCF77ValuesDay]+DCF77Values[DCF77ValuesMonth]+DCF77Values[DCF77ValuesYear]);
}

void fAffTime() {
  output_bit(LED_Error, RadioError);
  printf("\r");
  printf("%2u:%02u:%02u ", Heure , Minute, Seconde );
}

void fAffDate() {
    printf("\n\r");  // next line
    printf( "%s", DOW[dayOfWeek-1] );
    printf(" %02u/%02u/%02u",  day,  month,  year  );
    DCF77LastDate = DCF77DateInt();
   
    printf(VT100HOME); // home
}


void main() {

  // --INIT RTC--
  setup_wdt(WDT_OFF);
  setup_timer_0( RTCC_INTERNAL | RTCC_DIV_1 ); // 13.1 mS
  setup_timer_1(T1_DISABLED);
  setup_timer_2(T2_DISABLED,0,1);
  // ------------

  setup_adc_ports(NO_ANALOGS);

  delay_ms(100) ;

  printf(VT100CLS) ;
  printf("DCF77 Clock(c)IS");
  delay_ms(1000);

  // initialise time for test
  Heure = 10;
  Minute = 26 ;
  Seconde = 0 ;

  enable_interrupts(GLOBAL);
  StartTimer() ;
 
  printf(VT100CLS);  // Clear screen

  while (true) {   

    if ( DCF77CycleOK ) {      // a complete cycles  is finished

      DCF77Decoding( DCF77ValuesMinute, DCF77ValuesYear );  // it is possible to ask decoding of a part of received data
                                                            // after testing of DCF77BitNbr
                                                            // if DCF77BitNbr is >= DCF77ValuesDay then you
                                                            // can already decode minutes and hours
                                                           
      DCF77CycleOK = false ;   // for decoding DCF77 only one time when a cycle is finished

      if ( DCF77TimeOk ) {     // if no parity errors
        DCF77TimeOk = false ;

        Seconde =   DCF77Sec ;
        Minute =    DCF77Values[DCF77ValuesMinute] ;
        Heure =     DCF77Values[DCF77ValuesHour] ;
        day =       DCF77Values[DCF77ValuesDay] ;
        dayOfWeek = DCF77Values[DCF77ValuesDayOfWeek] ;
        month =     DCF77Values[DCF77ValuesMonth] ;
        year  =     DCF77Values[DCF77ValuesYear] ;

        if ( DCF77LastDate != DCF77DateInt() ) fAffDate() ;  //
       
      }
    }

    if ( SecondeFlag ) {  // refresh time each seconds
      fAffTime();
      SecondeFlag = 0;
    }

  }

}


And calcDCF77.c
Code:

void DCF77Decoding( int first, int last ) {
 int i,j, DCF77BitWeightSubscr ;
 int calcStart, calcEnd ;
 short parityTest ;

  RadioError = false ;

  for( j=first; j <= last; j++ ) {
    DCF77Values[j] = 0 ;
    calcStart = DCF77Scheme[j] ;
    calcEnd   = DCF77Scheme[j+1] ;

    parityTest = bit_test( calcEnd, 7 ) ;
    bit_clear(calcEnd, 7 );
   
    DCF77BitWeightSubscr = 0 ;
    for( i=calcStart; i < calcEnd; i++ ) {
      if ( DCF77Bits[i] ) {
        DCF77Values[j] += DCF77BitWeight[DCF77BitWeightSubscr] ;
        RadioParity = !RadioParity ;
      }
      ++DCF77BitWeightSubscr ;
    }
   
    if ( parityTest ) {
      RadioError = ( RadioParity != DCF77Bits[calcEnd] ) ;
      RadioParity = 0 ;
      j++ ;
    }
    if ( RadioError ) break ;
  }
 
 
  // -- The  autonomous clock  will add a minute because second is just set at 0 then minute - 1 ---
  //    not necessary without autonomous clock
  if ( !RadioError ) { 
    if (!DCF77Values[DCF77ValuesMinute]--) {
      DCF77Values[DCF77ValuesMinute] = 59;
      if(!DCF77Values[DCF77ValuesHour]--) DCF77Values[DCF77ValuesHour] = 23 ;
    }
  }
  // --------------------------------------------------------------------------------------
 
  DCF77TimeOk = !RadioError ;

}



Your commentary and/or suggestions are welcome.

dro.
_________________
in médio virtus


Last edited by inservi on Mon May 19, 2008 4:14 am; edited 8 times in total
inservi



Joined: 13 May 2007
Posts: 127

View user's profile Send private message

PostPosted: Mon Oct 08, 2007 3:31 am     Reply with quote

Hello,

The version with data stocked in bit is there ! (Is about less than 50 bytes of data saved).


--------------------------------------
little enhancement
Update the October 11 2007
removing 'day' from element to char const DOW and add one time in printf
--------------------------------------
--------------------------------------
BIG ERROR CORRECTING
the October 12 2007
added bit_clear(DCF77Bits[DCF77ByteNbr],DCF77BitNbr);
before DCF77Bits[DCF77ByteNbr] |= RadioBit<<DCF77BitNbr ;

some little enhancement in DCF77Decoding.c
--------------------------------------
the October 14 2007
little correction in weekday
--------------------------------------

-----------------------------------------------------------------------
the june 19 2008
improvement for zero drift timer from ckielstra
-----------------------------------------------------------------------

Code:
////////////////////////////////////////////////////////////////////////////
//               DCF77 DECODER                                            //
//                                                                        //
//  Writen by Daniel ROBERT  V1.1    08 october 2007                      //
//                                                                        //
//                                                                        //
//  Although the radio transmission of DCF77 signal is not                //
//  highly reliable, it can be practical to use it for time               //
//  initialisation.                                                       //
//  It is appropriate then to manage the real houre progression           //
//  with an autonomous clock.                                             //
//                                                                        //
//  If receiver DCF77 is used to maintain the hour  continually,          //
//  it is necessary to check at each end of cycle ( each minute )         //
//  if the new hour is well corresponding to the previous one plus        //
//  one minute. In any way an autonomous (internal) clock is needed       //
//  to allows to maintain the hour right for several minute because       //
//  of some parasite can easily block the reception for a long time.      //
//                                                                        //
//  In some environments, it is difficult to get a right signal           //
//                                                                        //
//  Three led are used for monitoring the reception progress.             //
//    LED_Error  is lighting when radio error                             //
//    LED_ZERO   is flashing when a zero is received                      //
//    LED_ONE    is flashing when a ONE is received                       //
//                                                                        //
//    LED_ZERO and LED_ONE   are lighting together (1 sec) at             //
//                           the start of cycle                           //
//                                                                        //
//  For demo, the result is sended to hyperterminal in VT100 mode         //
//                                                                        //
//  At starting, nothink appens until the 'start' is received (that       //
//  can take almost one minute) Then the two data led are blinking        //
//  togther 1 seconde. After that, the led ONE and ZERO must blink        //
//  one at the time, until the end of cycle. In case of radio error,      //
//  the Error led start lighting until the next start. Then the cycle     //
//  is restarting.                                                        //
//                                                                        //
//  This code will easily work on most PIC with CCS C V 3.x and V 4.x     //
//                                                                        //
////////////////////////////////////////////////////////////////////////////

#include "18F2620.h"

#FUSES NOWDT                   //No Watch Dog Timer
#FUSES WDT128                  //Watch Dog Timer uses 1:128 Postscale
#FUSES HS                      //High speed Osc (> 4mhz)
#FUSES NOPROTECT               //Code not protected from reading
#FUSES IESO                    //Internal External Switch Over mode enabled
#FUSES BROWNOUT                //Reset when brownout detected
#FUSES BORV21                  //Brownout reset at 2.1V
#FUSES PUT                     //Power Up Timer
#FUSES NOCPD                   //No EE protection
#FUSES STVREN                  //Stack full/underflow will cause reset
#FUSES NODEBUG                 //No Debug mode for ICD
#FUSES NOLVP                   //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOWRT                   //Program memory not write protected
#FUSES NOWRTD                  //Data EEPROM not write protected
#FUSES NOEBTR                  //Memory not protected from table reads
#FUSES NOCPB                   //No Boot Block code protection
#FUSES NOEBTRB                 //Boot block not protected from table reads
#FUSES NOWRTC                  //configuration not registers write protected
#FUSES NOWRTB                  //Boot block not write protected
#FUSES FCMEN                   //Fail-safe clock monitor enabled
//#FUSES XINST                   //Extended set extension and Indexed Addressing mode enabled
#FUSES NOPBADEN                //PORTB pins are configured as digital I/O on RESET
#FUSES LPT1OSC                 //Timer1 configured for low-power operation
#FUSES MCLR                    //Master Clear pin enabled

//------------------- FOR EASY ZERO DRIFT TIMER -------------------
#define FOSC                 20000000   // used for setup delay and calculate the zero drift timmer
#define DCF77TimerDepth      65536      // for 16 bit timer
#define DCF77TimerPrescaler  1          // for prescaler div by 1
//------------------- FOR EASY ZERO DRIFT TIMER -------------------
 
#use delay(clock=FOSC)



#define LCD_TX     PIN_C6
#define LCD_RX     PIN_C6
#define LCD_BAUD   4800

#define RADIO_PORT     PIN_C2   // input from DCF77 receiver
#define LED_Error      PIN_A2   // led indicating DCF77 error
#define LED_ZERO       PIN_A3   // led indicating a zero from DCF77
#define LED_ONE        PIN_A4   // led indicating a one from DCF77

#define RADIO_PORT_HIGH  input(RADIO_PORT)
#define RADIO_PORT_LOW  !input(RADIO_PORT)

#use RS232(baud=LCD_BAUD, xmit=LCD_TX , rcv=LCD_RX )

#define VT100LF      "%c[B", 27   // "%c%c",13,10
#define VT100CLS     "%c[2J", 27  //"%c",12
#define VT100HOME    "%c[H", 27

// --RTC--
#define RadioLength0         10    // not used - length of pulse for a zero
#define RadioLength1         15    // 150 ms minimum (normalement 160 minimum 200 tipicaly)
#define RadioLengthStart     100   // normaly, 1 sec then 100

#define RadioStartMinute     21    // position of first bit of minute in dcf77 scheme
#define RadioParityMinute    28    // same story for next element
#define RadioStartHeure      29    //    "
#define RadioParityHeure     35    //    "
#define RadioStartDay        36    //    "
#define RadioStartDayOfWeek  42    //    "
#define RadioStartMonth      45    //    "
#define RadioStartYear       50    //    "
#define RadioParity3         58    //    "

#define DCF77ValuesMinute     0    // element number is scheme
#define DCF77ValuesHour       2    // same story for next element
#define DCF77ValuesDay        4    //    "
#define DCF77ValuesDayOfWeek  5    //    "
#define DCF77ValuesMonth      6    //    "
#define DCF77ValuesYear       7    //    "

//------------------- FOR EASY ZERO DRIFT TIMER -------------------
#define DCF77InteruptTime    0.01   // sec
#define DCF77SetTimer   (int16)( DCF77TimerDepth * DCF77TimerPrescaler ) - (int16)( DCF77InteruptTime * (FOSC / 4) )
//------------------- FOR EASY ZERO DRIFT TIMER -------------------

// --------- GLOBAL DECLARATION --------------
int8       DCF77Bits[9] = {0} ;   // table for put all DCF77 bits for one cycle
int8 const DCF77BitWeight[8] = {1,2,4,8,10,20,40,80};
char const DOW[7][8] = { {"Mon\0"}, {"Tues\0"}, {"Wednes\0"}, {"Thurs\0"}, {"Fri\0"}, {"Satur\0"}, {"Sun\0"} } ;

                           // | 128 for set the bit 7  for indicate that it is a parity bit
int8 const DCF77Scheme[9]= { RadioStartMinute, RadioParityMinute | 128, RadioStartHeure, RadioParityHeure | 128,
                             RadioStartDay, RadioStartDayOfWeek, RadioStartMonth, RadioStartYear, RadioParity3 | 128 } ;                       
                             
int8       DCF77Values[9] = {0} ;
int8       DCF77Sec ;
int8       DCF77LastDate = 0 ;
short      DCF77TimeOk = false, DCF77CycleOK = false ;
int8       LastRadioTime = 0 ;
int8       DCF77Pulse = 0 ;                // lenght of pulse is hundredth (sec/100) of Sec
short      RadioBit , RadioParity ;
int8       DCF77BitNbr = 0, DCF77ByteNbr = 0 ;
short      RadioWaitStart = true, RadioWaitHight, RadioHightMesure ;
int8       heure = 0, Minute = 0, Seconde = 0 ;
int8       day = 0, dayOfWeek = 0, month = 0, year = 0 ;
int8       Sec100 ;
short      SecondeFlag = 0, MinuteFlag = 0 ;
short      RadioError = false ;


#int_timer0
void timer0_isr() {
//------------------- FOR EASY ZERO DRIFT TIMER -------------------
  set_Timer0( get_timer0() + DCF77SetTimer ); // for exactly 100 mSec
//------------------- FOR EASY ZERO DRIFT TIMER -------------------

  // -- autonomous clock --
  if (++Sec100 == 100) {
    Sec100 = 0 ;
    SecondeFlag = 1 ;
   
    if (++DCF77Sec == 60) DCF77Sec = 0 ; // count hundredth (1/100) of second  for DCF77
   
    if (++Seconde == 60) {            // hours
      Seconde = 0;
      MinuteFlag = 1;
      if (++Minute == 60) {           // hours
        Minute = 0 ;
        if (++heure == 24) heure = 0 ; // days
      }
    }
  }
  // --------------------

  if (++DCF77Pulse >= RadioLengthStart) {   //if low for at least 1 sec then start or error. Assume start
    RadioWaitStart = true ;
    RadioWaitHight = false ;
    RadioHightMesure = false ;
  }

  if (RadioWaitStart) { // wait for starting cycle. the length is at least 1 second
    if ( RADIO_PORT_HIGH ) {
      DCF77Pulse = 0 ; // reset if in high pulse ( after an error ) for mesure from start of zero     
    }
    if (DCF77Pulse >= RadioLengthStart) { // starting cycle
      RadioError = false ;
      output_high(LED_ZERO);   //
      output_high(LED_ONE);    // At start, the two led (one and zero) are blinking together
      DCF77Pulse =0 ;          // reset hundredth count
      RadioWaitStart = false ;
      RadioWaitHight = true ;  // past to next step wait for begin of hight pulse
      DCF77ByteNbr = 0 ;
      DCF77BitNbr = 0 ;
      DCF77Sec = 59 ;          // init secondes
    }
  }

  if (RadioWaitHight) { // wait for start of hight pulse
    if ( RADIO_PORT_HIGH ) {
      DCF77Pulse = 0 ;
      RadioWaitHight = false ;
      RadioHightMesure = true ;
      output_low(LED_ZERO);
      output_low(LED_ONE);
    }
  }

  if (RadioHightMesure) {   // mesure the lengh of higth pulse
    if ( RADIO_PORT_LOW ) { // end of high pulse, now DCF77Pulse contain the length of high pulse
      RadioBit = (DCF77Pulse >= RadioLength1) ;   // if DCF77 high pulse is greater than 160mS is 1 else is 0
      if ( DCF77Pulse > 25 || DCF77Pulse < 8 ) {  // if DCF77 high pulse is greater than 210mS or smaller 90mS then error
        RadioError = true ;
        RadioWaitStart = true ;                   // restart the waiting for start pulse (no signal for 1 sec)
      }

      DCF77Pulse = 0 ;                            // reset counter for pulse length
      bit_clear(DCF77Bits[DCF77ByteNbr],DCF77BitNbr); 
      DCF77Bits[DCF77ByteNbr] |= RadioBit<<DCF77BitNbr ;         // put bit into table

      if (++DCF77BitNbr == 8) {
        DCF77BitNbr = 0 ;
        ++DCF77ByteNbr ;
      }
      if (DCF77ByteNbr == 7 && DCF77BitNbr == 3) {  // if end of cycle (7*8) + 3 = 59
        RadioWaitStart = true ;
        DCF77CycleOK = true ;
      }
      RadioHightMesure = false ;
      RadioWaitHight = !RadioWaitStart  ;         // back to wait for next hight pulse if cycle not finished and no error

      // --- can be deleted --- juste for monitoring
      output_bit(LED_ZERO, !RadioBit ) ;         
      output_bit(LED_ONE,   RadioBit ) ;
      // ----------------------

    }
  }
}

#include <calcDCF77-8.c>


void StartTimer() {
  Sec100 = 0 ;
  set_Timer0( DCF77SetTimer );
  enable_interrupts(INT_TIMER0);
}

void StopTimer() {
  DISABLE_INTERRUPTS(INT_TIMER0);
}

int DCF77DateInt() { 
  return(DCF77Values[DCF77ValuesDay]+DCF77Values[DCF77ValuesMonth]+DCF77Values[DCF77ValuesYear]);
}

void fAffTime() {
  output_bit(LED_Error, RadioError);
  printf("\r");
  printf("%2u:%02u:%02u ", Heure , Minute, Seconde );
}

void fAffDate() {
    printf("\n\r");  // next line
    printf( "%sday", DOW[dayOfWeek-1] );
    printf(" %02u/%02u/%02u",  day,  month,  year  );
    DCF77LastDate = DCF77DateInt();
   
    printf(VT100HOME); // home
}


void main() {

  // --INIT RTC--
  set_timer0(0) ;
  setup_timer_0(RTCC_INTERNAL);
  setup_timer_2(T2_DIV_BY_16,196,16);
  // ------------

  setup_adc_ports(NO_ANALOGS);
  setup_adc(ADC_CLOCK_DIV_2);
  setup_spi(FALSE);
  setup_timer_1(T1_DISABLED);
  setup_ccp1(CCP_OFF);
  setup_ccp2(CCP_OFF);

  delay_ms(100) ;


  printf(VT100CLS) ;
  printf("DCF77 Clock(c)IS");
  delay_ms(1000);

  // initialise time for test
  Heure = 10;
  Minute = 26 ;
  Seconde = 0 ;

  enable_interrupts(GLOBAL);
  StartTimer() ;
 
  printf(VT100CLS);  // Clear screen

  while (true) {   

    if ( DCF77CycleOK ) {      // a complete cycles  is finished

      DCF77Decoding( DCF77ValuesMinute, DCF77ValuesYear );  // it is possible to ask decoding of a part of received data
                                                            // after testing of DCF77BitNbr
                                                            // if DCF77BitNbr is >= DCF77ValuesDay then you
                                                            // can already decode minutes and hours
                                                           
      DCF77CycleOK = false ;   // for decoding DCF77 only one time when a cycle is finished

      if ( DCF77TimeOk ) {     // if no parity errors
        DCF77TimeOk = false ;

        Seconde =   DCF77Sec ;
        Minute =    DCF77Values[DCF77ValuesMinute] ;
        Heure =     DCF77Values[DCF77ValuesHour] ;
        day =       DCF77Values[DCF77ValuesDay] ;
        dayOfWeek = DCF77Values[DCF77ValuesDayOfWeek] ;
        month =     DCF77Values[DCF77ValuesMonth] ;
        year  =     DCF77Values[DCF77ValuesYear] ;

        if ( DCF77LastDate != DCF77DateInt() ) fAffDate() ;  //
       
      }
    }

    if ( SecondeFlag ) {  // refresh time each seconds
      fAffTime();
      SecondeFlag = 0;
    }

  }

}


And the calcDCF77-8.c
Code:
void calcIndices(int8 indice, int8 *ByteNbr, int8 *BitNbr) {
  *ByteNbr= indice / 8 ;
  *BitNbr = indice - ( *ByteNbr * 8 ) ;
}

void DCF77Decoding( int first, int last ) {
 int8   i,j, DCF77BitWeightSubscr ;
 int8   calcStart, calcEnd ;
 short  parityTest ;
 int8   ByteNbr, BitNbr ;

  RadioParity = 0 ;
  RadioError = false ;

  for( j=first; j <= last; j++ ) {
    DCF77Values[j] = 0 ;
    calcStart = DCF77Scheme[j] ;
    calcEnd   = DCF77Scheme[j+1] ;

     parityTest = bit_test( calcEnd, 7 ) ;
     bit_clear(calcEnd, 7 );

    DCF77BitWeightSubscr = 0 ;
    for( i=calcStart; i < calcEnd; i++ ) {
      calcIndices( i, &ByteNbr, &BitNbr ) ;
      if ( bit_test( DCF77Bits[ByteNbr], BitNbr ) ) {
        DCF77Values[j] += DCF77BitWeight[DCF77BitWeightSubscr] ;
        RadioParity = !RadioParity ;
      }
      ++DCF77BitWeightSubscr ;
    }

    if ( parityTest ) {
      calcIndices( calcEnd, &ByteNbr, &BitNbr ) ;
      RadioError = ( RadioParity != bit_test( DCF77Bits[ByteNbr], BitNbr ) ) ;
      RadioParity = 0 ;
      j++ ;
    }
    if ( RadioError ) break ;
  }

  // -- The  autonomous clock  will add a minute because second is just set at 0 then minute - 1 ---
  //    not necessary without autonomous clock
  if ( !RadioError ) { 
    if (!DCF77Values[DCF77ValuesMinute]--) {
      DCF77Values[DCF77ValuesMinute] = 59;
      if(!DCF77Values[DCF77ValuesHour]--) DCF77Values[DCF77ValuesHour] = 23 ;
    }
  }
  // --------------------------------------------------------------------------------------

  DCF77TimeOk = !RadioError ;

}



dro.
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