flashled8051/flash.c

#include <8052.h>

#ifndef FLASH_PIN 
#define FLASH_PIN _P1_0
#endif

#ifndef IRQFREQ
#define IRQFREQ 1000L
#endif

#define FOSC (SYSCLK*1000L)

#define T0_1MS	(65536L-FOSC/12L/IRQFREQ)

#define TCT IRQFREQ/2-1

unsigned char ctr_l =  TCT&0xFF;
unsigned char ctr_h = (TCT>>8)&0xff;
unsigned char ctr_w = (TCT>>16)&0xff;

void handler() __interrupt 1 
{
	EA=0;
	__asm
	mov a, #0xff
	dec _ctr_l
	cjne a,_ctr_l, 00001$
	dec _ctr_h
	cjne a,_ctr_h, 00001$
	dec _ctr_w
	cjne a,_ctr_w, 00001$

	cpl  FLASH_PIN
	__endasm;
	
	ctr_l =  TCT&0xFF;
	ctr_h = (TCT>>8)&0xff;
	ctr_w = (TCT>>16)&0xff;

	__asm
	00001$:
	__endasm;
	EA=1;
}


void main()
{
	
	P1=TMOD;

	EA=0;

	TMOD =0; 
	P1=TMOD;

	TL0 = (T0_1MS) & 0xFF; 	// Initial timer value
    	TH0 = T0_1MS>>8;	// Initial timer value


	TR0 = 1;		// Timer0 start run
	ET0 = 1;		// Enable timer0 interrupt
	EA=1;

	while(1);
}