vorher
Binäre Sketchgröße: 24.594 Bytes

unsigned char compile_time(void)
{ uint8_t cc, jj=0, mo=0, ta=0, hh=0, mm=0, ss=0;
  uint16_t jjjj=0, tn=0;
  char buffer_l[15];
  char buffer[4];

  strcpy(buffer_l, __DATE__);
  jjjj=atoi(rights(buffer_l, (uint8_t)4));
  jj=atoi(rights(buffer_l, (uint8_t)2));
  ta=atoi(mids(buffer_l, (uint8_t)5, (uint8_t)2));
  for(cc=1; cc<13; cc++)
  { strcpy_P(buffer, (char*)pgm_read_word(&(mo_table[cc]))); // Necessary casts and dereferencing, just copy. 
    if(!strcmp((char *)lefts(buffer_l, (uint8_t)3), (char *)buffer))
    { mo=cc; break; }
  } // for(cc=1; cc<13; cc++)
  strcpy(buffer_l, __TIME__);
  hh=atoi((char *)lefts(buffer_l, 2));
  mm=atoi((char *)mids(buffer_l, 4, 2));
  ss=atoi((char *)rights(buffer_l, 2));

  sprintf((char *)c_str,"%04d/%02d/%02d_%02d:%02d:%02d", jjjj, mo, ta, hh, mm, ss);
  if(jjjj>0 && jj>0 && mo>0 && ta>0 && hh>0 && mm>0 && ss>0 && tn>0)
    return (uint8_t)1;
  else
    return (uint8_t)0;
} // unsigned char compile_time(void)

nachher
Binäre Sketchgröße: 24.436 Bytes

unsigned char compile_time(void)
{ 
  uint8_t cc=1, mo=0, ta=0, hh=0, mm=0, ss=0;
  uint16_t jjjj=0;
  jjjj = (__DATE__[7] - '0') * 1000 + (__DATE__[8] - '0') * 100 + (__DATE__[9] - '0') * 10 + __DATE__[10] - '0';
  (__DATE__[4]==' ') ? ta = __DATE__[5] - '0' : ta = (__DATE__[4] - '0') * 10 + __DATE__[5] - '0';
  while(cc++<13)
  { if(!strncmp_P(__DATE__, (char*)pgm_read_word(&(mo_table[cc])), 3))
    { mo=cc; break; }
  } // for(cc=1; cc<13; cc++)
  hh = (__TIME__[0] - '0') * 10 + __TIME__[1] - '0';
  mm = (__TIME__[3] - '0') * 10 + __TIME__[4] - '0';
  ss = (__TIME__[6] - '0') * 10 + __TIME__[7] - '0';
  sprintf((char *)c_str,"%04d/%02d/%02d_%02d:%02d:%02d", jjjj, mo, ta, hh, mm, ss);
  if(jjjj>0 && mo>0 && ta>0 && hh>=0 && mm>=0 && ss>=0)
    return (uint8_t)1;
  else
    return (uint8_t)0;
} // unsigned char compile_time(void)