/*********************************************************************
*                                                               		*
*   Filename:      led_flash.c													*
*   Date:          30/12/2012                                        *
*   Version:  		 1.0                                             	*
*   Author:        Goran Ljubic		                                 *
*                                                                    *
**********************************************************************
*                                                                    *
*   Architecture:  Microchip PIC Enhanced Mid-range Core             *
*   Processor:     16F1827                                           *
*   Compiler:      MPLAB XC8 v1.12 (Free mode)                       *
*                                                                    *
**********************************************************************
*                                                                    *
*   Description:    Primer 2				                              *
*                                                                    *
*   LED diode od D1 do D8 se ukljucuju i iskljucuju jedna za drugom  *
*   sa vremenskim razmakom od 300ms. Nakon toga redosled ukljucenja  *
*   i iskljucenja se menja.                                          *
*                                                                    *
*********************************************************************/

#include <xc.h>

#define _XTAL_FREQ  4000000     // frekvencija internog oscilatora.

/******************************************************************************************************************************
																																										*
CONFIGURATION WORDS																																				*
Watchdog timer is disabled, Internal RC oscillator I/O function on CLKIN pin, MCLR/VPP pin function is digital input, 			*
Program memory code protection is disbled, Brown-out Reset disabled, Power-up timer enabled, 											*
Data memory code protection is enabled, CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin,				*
Internal/External Switchover mode is disabled, Fail-Safe Clock Monitor is disabled, 														*
000h to FFFh flash memory write protected, 4x PLL disabled, Stack Overflow or Underflow will not cause a Reset,					*
High-voltage on MCLR/VPP must be used for programming																									*
																																										*
******************************************************************************************************************************/

   __CONFIG(WDTE_OFF & FOSC_INTOSC & MCLRE_OFF & CP_OFF & BOREN_OFF & PWRTE_ON & CPD_ON & CLKOUTEN_OFF & IESO_OFF & FCMEN_OFF); 
   __CONFIG(WRT_ALL & PLLEN_OFF & STVREN_OFF & LVP_OFF); 



unsigned char i;		// brojacka promenljiva
bit DIR;					// bit koji nam govori u kom smeru ide ukljucenje i iskljucenje LED dioda

/******************************
*	   	MAIN PROGRAM			*		
******************************/

void main(void)
{

/******************************
*		INITIALISATION				*
******************************/

	OSCCON = 0b01101010;		// 4x PLL is disabled, 4 MHz HF Internal oscillator block 

	TRISA = 0b11111111;		// Svi pinovi porta A konfigurisani kao ulazni

	TRISB = 0;					// Svi pinovi porta B konfigurisani kao izlazni

	LATB = 0x01;				// pocetno ukljucena samo LED1

	DIR = 1;						// postavljen pocetan smer kretanja

/******************************
*  		MAIN LOOP				*
******************************/

   for (;;)						// beskonacna petlja
	{
		for(i=0;i<7;i++)		// sledecih 7 LED cemo redom ukljucivati i iskljucivati
		{
			__delay_ms(300);	// sa vremenskim razmakom od 300ms

			if(DIR)				// U zavisnosti od trenutnog smera
			{	
				LATB <<= 1;		// stanje na izlaznim pinovima PORT-a B se pomera za jedno mesto ulevo
			}
			else					// ili 
			{
				LATB >>= 1;		// udesno
			}		
		}
		DIR = ~DIR;				// Po završetku jednog ciklusa smer se menja
	}
}