[Jerry]

Chạy được rồi này, vấn đề đúng là nằm ở gạch đầu dòng thứ 2 và thứ 3 của bác Nam

#include <16F877A.h>
#include <def_877a.h>
#device *=16 adc=10
#FUSES NOWDT, XT, NOPUT, NOPROTECT, NODEBUG, NOBROWNOUT, NOLVP, NOCPD, NOWRT
#use delay(clock=4000000)
#use fast_io (b)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=9)

#define OK PIN_B6
#define Cancel PIN_B7

#define OK_PRESSED  !input(OK)

#include <lcd_lib_4bit.c>

   int8 count;
   char phim;
   int8 isr_count,press;

#int_TIMER0
void interrupt_timer0()
{
   if(OK_PRESSED)
   {
      isr_count++;
      if(isr_count==81)
      {
         isr_count=0;
         press=1;
         disable_interrupts(GLOBAL);
         disable_interrupts(INT_TIMER0);
      }
   }
   else
   {
      press=0;
      disable_interrupts(GLOBAL);
      disable_interrupts(INT_TIMER0);
   }
}

//-----------------------------------------------------------------

void main(void)
{
   press=0;
   output_b(0xC0);
   set_tris_a(0xC0);
   set_tris_b(0xC1);
   port_b_pullups (TRUE);

   LCD_init();
   delay_ms(500);
   LCD_putcmd(0x80);
   Printf(LCD_putchar,"Hi ev'body");   //Hien thi man hinh 1
   LCD_putcmd(0xC0);
   Printf(LCD_putchar,"Khoi tao...");

   while (!OK_PRESSED) { }
              //enable timer0
      set_timer0(6);
      setup_timer_0(RTCC_INTERNAL);
      enable_interrupts(INT_TIMER0);
      enable_interrupts(GLOBAL);
   
   while(press!=1) {}
      LCD_putcmd(0x01);    //xoa man hinh
      LCD_putcmd(0x80);
      Printf(LCD_putchar,"Enter Pressed");  //Hien thi man hinh 2

}