Easy interrupt setup

Technical Programming
1

I made this code to ease using interrupts - I spent most of a day reading documentation and testing things, so I figured that I’d share the code.

RobotUtils.h

/*				RobotUtils.h			*\
|*		Interface with the more			*|
|*		advanced controller features	*|
|*		Created 2004 by					*|
\*			Steven Schlansker			*/

#include "ifi_picdefs.h"
#include "printf_lib.h"

typedef void (*int_func)(void);


typedef enum { falling, rising } edge;

void interrupt_pin1(int_func,edge which);
void interrupt_pin2(int_func,edge which);
void interrupt1();
void interrupt2();

RobotUtils.c

#include "RobotUtils.h"
#define bitbyte(c) (1 << c)

int_func pin1,pin2;

void interrupt_pin1(int_func func,edge which){
	pin1 = func;
	if(func){
		INTCON	|= bitbyte(7);
		if(which == rising)
			INTCON2	|= bitbyte(4);
		else
			INTCON2	&= ~bitbyte(4);
		INTCON3	&= ~bitbyte(7);
		INTCON3 |= bitbyte(4);
	}else{
		INTCON3 &= ~bitbyte(4);
	}
}

void interrupt_pin2(int_func func,edge which){
	pin2 = func;
	if(func){
		INTCON	|= bitbyte(7);
		if(which == rising)
			INTCON2	|= bitbyte(3);
		else
			INTCON2	&= ~bitbyte(3);
		INTCON2 &= ~bitbyte(1);
		INTCON3 |= bitbyte(5);
	}else{
		INTCON3 &= ~bitbyte(5);
	}
}

void interrupt1(){ pin1(); }
void interrupt2(){ pin2(); }

user_routines_fast.c (Only modify the lines which are shown here)

void InterruptHandlerLow ()     
{                               
  unsigned char int_byte;       
  if (INTCON3bits.INT2IF)         /* The INT2 pin is RB2/DIG I/O 1. */
  { 
	 interrupt1();
    INTCON3bits.INT2IF = 0;
  }
  else if (INTCON3bits.INT3IF)    /* The INT3 pin is RB3/DIG I/O 2. */
  {
	  interrupt2();
    INTCON3bits.INT3IF = 0;
  }
  else if (INTCONbits.RBIF)       /* DIG I/O 3-6 (RB4, RB5, RB6, or RB7) changed. */
  {
    int_byte = PORTB;           /* You must read or write to PORTB   */
    INTCONbits.RBIF = 0;        /* and clear the interrupt flag      */
  }                             /* to clear the interrupt condition. */
}

Good luck.

2

Thanks. :smiley:

3

Glad you posted this, but could you clairify what exactly RoboUtils.c does? It has a lot of bitshiffting and other bitwise operations which are hard to follow. Maybe a few comments? :slight_smile:

4

Yeah, it changes a few registers around, specifically the INTCON registers. For a description of the bits, refer to the Microchip documentation on the PIC. I might write comments eventually if I get a chance…