//==================================================
// Written By: Chia Chen Tan
// Program: Basic Up Counter for ChipScope
//==================================================
//
// This program will utilize push button to control
// the up counter constant. Chipscope is used to 
// detect the rapid signal change in the output.
//==================================================
#include "xparameters.h"
#include "xstatus.h"
#include "xgpio.h"
	
#define DELAY 1024

#define ENTER	15  //0b01111
#define UP		23  //0b10111
#define DOWN	27  //0b11011
#define LEFT	29  //0b11101
#define RIGHT	30  //0b11110
	
int main(void)
{
	//=================================================
	// Initialize and set direction for LED and PB 
	//=================================================
	XStatus LED_status, PB_status;
	XGpio GpioOutput, GpioInput;
	Xuint32 current_PB;
	
	LED_status = XGpio_Initialize(&GpioOutput, XPAR_LEDS_4BIT_DEVICE_ID);
	PB_status = XGpio_Initialize(&GpioInput, XPAR_PUSHBUTTONS_5BIT_DEVICE_ID);
	XGpio_SetDataDirection(&GpioOutput, 1, 0x0);
	XGpio_SetDataDirection(&GpioInput, 1, 0xFFFFFFFF);
	
	Xuint8 counter = 0;
	Xuint8 constant = 0;
	int i;
	
	XGpio_DiscreteWrite(&GpioOutput, 1, 0xFFFFFFFF);
	
	while(1){
	
		//=================================================
		// Read the data off of the Push Button
		//=================================================
		current_PB = XGpio_DiscreteRead(&GpioInput, 1);
		
		//different direction corresponds to different up counter constant 
		switch ( current_PB ){
		
			//+1 up counter
			case UP:	constant = 1;
						break;
			
			//+2 up counter
			case DOWN:	constant = 2;
						break;
						
			//+3 up counter
			case LEFT:	constant = 3;
						break;
						
			//+4 up counter
			case RIGHT:	constant = 4;
						break;
						
			//no addition
			default: constant = 0;
						break;
		}
	
		//use a nested for loop to lessen cycle delay in switch operation
		for (i = 0; i < DELAY; i++)
		{
			//=================================================
			// send the data back out to the LEDs.
			//=================================================
			XGpio_DiscreteWrite(&GpioOutput, 1, counter);
		
			counter += constant;
		}
		
		//reset counter
		counter = 0;
	}
	
	return 0;
}