intr.c

pic单片机例程

#include	<htc.h>

/*
 *	Interrupt test for PIC 
 *
 *	Copyright (C)1997 HI-TECH Software.
 *	Freely distributable.
 */

static volatile long	count;
static volatile bit	bad_intr;

void
main(void)
{
	/* setup stuff */

	T0CS = 0;		// Timer increments on instruction clock
	TRISB = 0xFE;		// Port B bit 0 is output 
	T0IE = 1;		// Enable interrupt on TMR0 overflow
	GIE = 1;		// Global interrupt enable
	for(;;)
		CLRWDT();	// Idly kick the dog
}

static void interrupt
isr(void)			// Here be interrupt function - the name is
				// unimportant.
{
	if(!T0IF)		// Was this a timer overflow?
		bad_intr = 1;	// NO! Shock horror!
	count++;		// Add 1 to count - insert idle comment
	T0IF = 0;		// Clear interrupt flag, ready for next
	PORTB ^= 1;		// toggle bit 0 of Port B, to show we're alive
}