// Inserts leading characters e.g. '0' or '_' in front of an integer Number converted to a string in order to make it to fixed length
// intValue   = Number (numerical) to be output as string with fixed length
// strDest    = Destination String that holds the changed result
// Base       = radix Base of conversion: 2 = binary representation, 10 regularly >10 does not work ! 
// InsertChar = Character to be inserted in front of converted number
// NoDigits   = No of characters to be output 
char * itoa_NoDigits( char * strDest, int intValue, char Base, char InsertChar, char NoDigits)
{ char firstLoop = true;
  strDest[(int) NoDigits] = '\0';                            // set NULL-character for string end
  while(NoDigits--)                                          // make number of loops to fill destination string
  { if( intValue )                                           // If intValue != 0 then...
      strDest[ (int) NoDigits] = '0' + (intValue % Base);    // fill in destination string - convert from number to ASCII character by addition of '0'
    else                                                     // If intValue == 0 then...
	{  if (firstLoop)
	     strDest[ (int) NoDigits] = '0';                     // insert exceptional "0" in case insertChar = blank in order to receive one "0"
	   else
	     strDest[ (int) NoDigits] = InsertChar;              // insert regular leading character           
	}
    intValue /= Base;                                        // prepare for next modulo operation i.e. cut away last digit.
    firstLoop = false;
  }
  return strDest;
} // itoa_NoDigits



// Converts DS1631 read temperatur to strDest[] prepared to be output as ASCII Text e.g. on a display
// Parameter: strDest:        prepared character array that holds the result string 
//            intTemp:        2 Byte Integer as read from DS1631 Sensor
//            DeicimalDigits: Number of decimal digits after comma to be displayed [0, 1, 2, 3, 4]
// Return Value: Pointer to string buffer that holds the converted result - without " Grad C"
// - works 15.02.10
char * itoa_DS1631_Temp( char * strDest, int intTemp, char DecimalDigits)  
{ unsigned intTempHighByte;          // high byte represents integer degrees in front of comma                                               
  unsigned intTempLowByte;           // low  byte represents decimal degrees after comma in higher nibble
  char tmpBuffer[5];
  if (intTemp & 0b1000000000000000)  // Temperature is negativ
  {  intTemp = (~ intTemp) + 1;      // Invers sign by2 complement over both !! bytes
     strcpy( strDest, "-" );         // set '-' sign
  }
  else
    strcpy( strDest, "+" );          // set '+' sign, what is also used for exactly zero degree
  intTemp >>=  4;                    // shift integer value so that used bits are at lowest bit position
  intTempLowByte  = (intTemp & 0b0000000000001111) * 625;// 8 high bits of intTemp are set to zero one level corresponds to 0,0625
  switch(DecimalDigits)                                  // add rounding number depending on number of decimals to be displayed
  { case 0: intTempLowByte += 5000; break;               // For rounding effect add: 0,5000  0,0500  0,0050  0,0005  0,0000
    case 1: intTempLowByte +=  500; break;               // ... depending on number of decimal digits to be displayed
    case 2: intTempLowByte +=   50; break;
    case 3: intTempLowByte +=    5; break;
  //case 4: intTempLowByte +=    0; break;               // There is nothing to round if all 4 possible decimals are to be displayed
  }
  intTempHighByte = intTemp >> 4;                        // in total shift right intTemp for high byte 8 times  
  if (intTempLowByte >= 10000)                           // make up for rounding effect that influences high-byte                                   	   	
    intTempHighByte++;                                   // only required if no decimals are to be displayed
  strcat(strDest, itoa_NoDigits(tmpBuffer, intTempHighByte, 10, ' ', 3) );  // Convert High byte to ASCII with leading blanks
  if ( DecimalDigits )                                          
    strcat( strDest, "," );                              // Place comma only if decimal digits are to be displayed
  itoa_NoDigits(tmpBuffer, intTempLowByte, 10, '0', 4);  // convert decimals to 4 digit incl. leading zeros in front of digits and after comma
  strncat( strDest, tmpBuffer, DecimalDigits );          // copy requested number of decimal digits to result string 
  return strDest;                                        // return pointer of composed string
} // itoa_DS1631_Temp