pict15c.c

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//<pre>
// pict15c.c
//
// Implementation of the PICT15.ASM program in Easy Pic 'N
// Interrupt demo.
//
// In this example, portB,0 is the interrupt source - the
// interrupt is done with a 'pulser' which is basically a
// debounced switch with a half monostable multivibrator.
// You can use a debounced switch alone to make it work.
// I have used an ordinary Radio Shack switch and let it
// bounce. It still works ok - just have to punch it a 
// couple of times to get the light to stay on.
//
// Using '84 on a board (simple solderless breadboard with
// 16F84 on it) and Peter Anderson's include file with 
// port/bit definitions (defs_f84.h available at www.phanderson.com)
// Settings:
// 	4Mhz resonator (not important)
//	All Port A inputs use external pullups (resistor 
//	SIP used)
//	Port B outputs tied to a LED array (Radio Shack 
//	has 'em)
//	Port A inputs tied to ground through five switches
//	(pullups still are on them - makes it all work!)
// 	Port A0 use for switch monitoring (for kicks - not
//	part of interrupt scheme). 
//      PortB0 is the Int source so it is
//      an input. A one shot is tied to portB0. (see the book
//      for more information, but you should be able to make
//      something that will work from this)
#case
#include <16f84.h>
#include <defs_f84.h>  // defines registers and bits
#fuses xt,nowdt,put,noprotect


#int_ext // see page 41 of the CCS manual - this is
	// the interrupt declaration. the function that
	// follows is the interrupt service routine
void iserv(void)
{	
	rb2=!rb2;  // flop the bit on rb2
        
}

void main(void)
{
   TRISA=0x1f;	// make porta inputs
   trisb0=1;	// make portb, bit 0 input (interrupt)
   trisb1=0;	// make portb, bit 1, 2 output
   trisb2=0;
   rb1=0;
   rb2=0;
   enable_interrupts(INT_EXT); // mandatory if you want externals
   enable_interrupts(GLOBAL); // mandatory to start it all

	// get this going and then toggle the portA0 switch
	// to see the normal switch monitoring, and then
	// pulse rb0 to see the interrupt work.
	//
   while(1)
   {
	if (ra0==1)	// monitor porta for switch (just 
			// for something to do while 
			// toggling interrupts)
		rb1=1;
	if (ra0==0)
		rb1=0;
   }
   	  
}