sbit LCD_RS at LATD2_bit;
sbit LCD_EN at LATD3_bit;
sbit LCD_D4 at LATD4_bit;
sbit LCD_D5 at LATD5_bit;
sbit LCD_D6 at LATD6_bit;
sbit LCD_D7 at LATD7_bit;
sbit LCD_RS_Direction at TRISD2_bit;
sbit LCD_EN_Direction at TRISD3_bit;
sbit LCD_D4_Direction at TRISD4_bit;
sbit LCD_D5_Direction at TRISD5_bit;
sbit LCD_D6_Direction at TRISD6_bit;
sbit LCD_D7_Direction at TRISD7_bit;

unsigned int oldstate;
char on;

void hello()
{
  if(on) Lcd_Cmd(_Lcd_Clear);
  else   Lcd_Out(1, 1, "hello");

  on = on ? 0 : 1;
}

void main()
{
  on = 0;

  Lcd_Init();
  Lcd_Cmd(_Lcd_Cursor_Off);
  AD1PCFG = 0xFFFF;
  TRISCbits.TRISC1 = 1;

  do
  {
    if (Button(&PORTC, 1, 1, 1))
      oldstate = 1;
    if (oldstate && Button(&PORTC, 1, 1, 0))
    {
      hello();
      oldstate = 0;
    }
  } while(1);
}

----------------------------------------------------------------------------------------

sbit LCD_RS at LATD2_bit;
sbit LCD_EN at LATD3_bit;
sbit LCD_D4 at LATD4_bit;
sbit LCD_D5 at LATD5_bit;
sbit LCD_D6 at LATD6_bit;
sbit LCD_D7 at LATD7_bit;
sbit LCD_RS_Direction at TRISD2_bit;
sbit LCD_EN_Direction at TRISD3_bit;
sbit LCD_D4_Direction at TRISD4_bit;
sbit LCD_D5_Direction at TRISD5_bit;
sbit LCD_D6_Direction at TRISD6_bit;
sbit LCD_D7_Direction at TRISD7_bit;

char on;

void ExtInt1() org 0x003C
{
  IFS1bits.INT1IF = 0;

  if(on) Lcd_Cmd(_Lcd_Clear);
  else   Lcd_Out(1, 1, "hello");

  on = on ? 0 : 1;
}

void main()
{
  Lcd_Init();
  Lcd_Cmd(_Lcd_Cursor_Off);
  AD1PCFG = 0xFFFF;
  IFS1bits.INT1IF = 0;
  IEC1bits.INT1IE = 1;

  while(1);
}
-----------------------------------------------------------------------------------------

sbit LCD_RS at LATD2_bit;
sbit LCD_EN at LATD3_bit;
sbit LCD_D4 at LATD4_bit;
sbit LCD_D5 at LATD5_bit;
sbit LCD_D6 at LATD6_bit;
sbit LCD_D7 at LATD7_bit;
sbit LCD_RS_Direction at TRISD2_bit;
sbit LCD_EN_Direction at TRISD3_bit;
sbit LCD_D4_Direction at TRISD4_bit;
sbit LCD_D5_Direction at TRISD5_bit;
sbit LCD_D6_Direction at TRISD6_bit;
sbit LCD_D7_Direction at TRISD7_bit;
//-------------------------------stopwatch------------------------------------//

unsigned int oldstate;
char on;
float f = 0.0;
char s1[16];

void timer1_int () org 0x1A
{
  IFS0 = IFS0 & 0xFFF7;      // izbrisi flag
  f += 0.064;
  FloatToStr(f, s1);
  Lcd_Out(2, 1, s1);
}

void timer_on()
{
  f = 0.0;
  T1CON = 0x8020;            //0b1000000000100000 - T1ON=1,TCS=0,TCKPS1=1,TCKPS0=0,
                             //preskaler 1:64
}

void timer_off()
{
  T1CONbits.TON = 0;
}

void timer()
{
  if(on) timer_off();
  else   timer_on();

  on = on ? 0 : 1;
}

void main()
{
  AD1PCFG = 0xFFFF;
  IEC0   = IEC0 | 0x0008;    // omoguci timer1 interrupt
  IFS0   = IFS0 & 0xFFF7;    // izbrisi flag

  PR1=5000;                  //podesi period timera

  Lcd_Init();
  Lcd_Cmd(_Lcd_Cursor_Off);
  Lcd_Out(1, 1, "TIMER:");

  TRISCbits.TRISC1 = 1;

  do
  {
    if (Button(&PORTC, 1, 1, 1))
      oldstate = 1;
    if (oldstate && Button(&PORTC, 1, 1, 0))
    {
      timer();
      oldstate = 0;
    }
  } while(1);

}