#include <pic.h>

/********************************************************
*  
* Program Title:     Flash D0 with Initialization and Delay Written in Mixed C and Assembly 
*
* Program File Name: Lecture_11B.c  
*
* Microprocessors B 17.384
*
* Spring 2009
*
* Dohn Bowden
*
* 04/18/2009  
*
********************************************************/




/********************************************************
* Function: main
*
* Description:  D0 on PICkit 1 will Flash on and off
*
* Notes:
*
* RA4 - Positive LED Connection for D0
* RA5 - Negative LED Connection for D0
*
* Returns:  This routine contains an infinite loop
*
********************************************************/


/* Configuration Word */

__CONFIG(INTIO & WDTDIS & PWRTEN & MCLRDIS & UNPROTECT \
  & UNPROTECT & BORDIS & IESODIS & FCMDIS);
  
void PORTA_init(void);

void delay_routine(void);

int count;

main()
{

	PORTA_init();

    	while(1 == 1)               	//  Loop Forever
    	{
		
			delay_routine();
			NOP();
       		RA4 = 1;                //  D0 LED On by making RA4 high

			delay_routine();

        	RA4 = 0;                //  D0 LED Off by making RA4 low

    	}  // *** END OF While (1 == 1) LOOP
 
	return;
 
}

/******** END OF main ROUTINE ***************************/

/********************************************************
* Function: PORT_init
*
* Description:  Initializes PORTA to a known condition
*
* Notes:    None
*
* Returns:  None
*
*
********************************************************/
void PORTA_init(void)
{
	// WAS the following
		//PORTA = 0;                  	//  All PORTA Pins are low
    	//CMCON0 = 7;                 	//  Turn off Comparators
    	//ANSEL = 0;                  	//  Turn off ADC
		//TRISA = 0b001111;		//  RA4 and 5 are outputs; RA0,1,2, and 3 are input
		
	// New code is the following ...
	
	#asm
		BCF 	_STATUS, 5  		;  //Select Bank 0
;
		CLRF 	_PORTA	   			;  //Initialize PORTA (to all zeros)
;
		MOVLW 	7	   				;  //Load w with 7 
		MOVWF 	_CMCON0	   			;  //Load CMCON0 with 7
			   						;  //Turns off comparators
;
		BSF 	_STATUS, 5 			;  //Select Bank 1
;
		CLRF 	_ANSEL      			;  //Shut off ADC (digital I/O)
;
		MOVLW	001111B 			;  //Load w – RA4 and RA5 outputs
		MOVWF	_TRISA				;  //copy w to TRIS PORTA 
; 
		BCF 	_STATUS, 5 			;  //Select Bank 0
	#endasm

	return;

}
/******** END OF PORTA_init ****************************/

/********************************************************
* Function: delay_routine
*
* Description:  Causes a delay in program execution
*
* Notes:
*
* Delay was determined through trial and error
*
* Returns:  None
*
********************************************************/
void delay_routine(void)
{
	// WAS the following
	// int i, j;
		
	// for (i = 0; i < 255; i++)  
    //		for (j = 0; j < 255; j++);
   // New code is the following ... 
      
		asm("			MOVLW	255")   				; //Decimal 255
		asm("			MOVWF	_count")				; //Initialize counter to 10
		asm("Repeat		DECFSZ	_count,f") 				; //Decrement counter
		asm("			GOTO	Repeat")	   			; //If counter <> 0
		
	return;

}
/******** END OF delay_routine *************************/