Hi,

Perhaps the included code is a little better. The rest of the code is just an LCD driver but there are a few functions and variable declared extern. Why the extern intrptcnt you may ask. I was doing some experimenting with extern and left it with the lcd.h "extern volatile unsigned long intrptcnt;" The code was meant to do LcdWriteString(" Hello World") or LcdClear() on every fourth flash.

What are you suggesting with the and operation? A bitwise and ??? Modulo was the only thing that came to mind.

Can you suggest a better way to count 1000 ticks (roughly one second)???

#include  <DS89C4xx.h>
#include "lcd.h"
#include "init8051.h"

sbit LED0 = P3^0;
sbit LED1 = P3^1;
sbit LED2 = P3^2;
sbit LED3 = P3^3;
sbit LED4 = P3^4;
sbit LED5 = P3^5;
sbit LED6 = P3^6;
sbit LED7 = P3^7;


volatile unsigned long count = 1000;
volatile unsigned char flash = 0;

intrptcnt = 0;

void Timer0_ISR (void) interrupt	1

{	
ET0 = 0;								 
TF0 = 0; //clear flag
intrptcnt++;
TL0 = 0xCC;
TH0 = 0xD4;
ET0 = 1;
}

void main (void)
{

P0 = 0xFF;	//turn off leds
initController();
delayMs(1000);
LcdInit();

  while(1)
  {
	if (intrptcnt == count)
	{
		LED0 = ~LED0;
		intrptcnt = 0;
		flash++;
		

			if (flash % 4 == 0)
			{
			  LcdWriteString("Hello World");
                           if (flash == 100) flash = 0;
			}
			else
			{
			  LcdClear();//clear
			}	
	}
	
  }
}


 

Cheers,
Lee.