//picl -16f627 -o -Zg -C main.c sci.c sci.h constants.h
//picl -16f627 main.obj sci.obj

//--------------------------------------------------------------
// libraries
//--------------------------------------------------------------
#include    <pic.h>
#include    "sci.h"
#include    "constants.h"

__CONFIG(WDTEN);

//--------------------------------------------------------------
// function declarations
//--------------------------------------------------------------
void interrupt button_isr(void);
unsigned char state;

//--------------------------------------------------------------
// main
//--------------------------------------------------------------
main(void)
{
	// -----------------------------------------------------------
   	// configure processor
	// -----------------------------------------------------------
	PORTA = 0xff;	// set output data latches to default value
	CMCON = 0x07;	// disable comparators to allow I/O
	TRISA = 0x00;	// all bits output
	TRISB = 0xF0;	// low 4 bits output, high 4 bits input
	PORTB = 0xFE;   // clear PortB
	OPTION = 0x7F;  // Set internal pull-up on portB
                        // Asign Postscalar to WDT
                        // Set ratio to 1:128

	INTCON = 0x88;	// setup interrupt control

	state = NO;

	// -----------------------------------------------------------
	// USART setup
	// -----------------------------------------------------------

	sci_Init();	// setup USART protocol

	// -----------------------------------------------------------
	// main code
	// -----------------------------------------------------------

	for(;;) {
		sci_PutByte(state);
		SLEEP();
	}
}

void interrupt button_isr(void)
{
	GIE = 0;	// disables all interrupts
	
	if(RBIF == 1){
              
              state = ((~state) & 0x0F);

              if(state == YES){
                 RB3 = 1;
              }else if (state == NO){
                 RB3 = 0;
              }

              RBIF = 0;
	}

	GIE = 1;	// enable all interrupts
}