#include "skp26.h"
#include "sfr262.h"
void main(void);
const char message[6][9]={//characters to be displayed.
{"Welcome "},{"ECGR6090"},
{"halassal"},{"salsassm"}
};
/*define the LEDs and switches ports*/
#define LED_R p7_0
#define LED_Y p7_1
#define LED_G p7_2
#define SW2 p10_5
#define SW3 p10_6
#define SW4 p10_7
unsigned long int m=0;//varaible to be used in solving the bouncing problem.
int cnt=0;
int det=0;
int SW2_p=0;
int SW3_p=0;
int SW4_p=0;
int rx_ok=1;
int A4_done=0;
int rx_array[8]={0,0,0,0,0,0,0,0};//array to store the received bits.
const int st_bit[3]={1,0,1};//starting bits to compare with.
const int sp_bit[2]={1,0};//stop bits to compare with.
void A0A1A4_init(void){//function to initialize timers.
	ta0=0x014D;//to generate 30khz
	ta1=0x0013;
	ta4=0x0255;//to get 10 msec.
	ta0mr=0x04;//timers mode to generate 30KHz
	ta1mr=0x0D;
	ta4mr=0x0D;//event count mode to get 10 msec.
	udf=0x00;
	trgsr=0xC2;
	asm("FCLR I");
	ta0ic=0x03;
	ta1ic=0x05;
	ta4ic=0x06;
	tabsr=0x00;
	asm("FSET I");
}
void P6_1_init(void){
	pd6_1=0;//port as input
	pu14=1;
}
void det_first(void){
	if(p6_1==0){
		det=1;//indicate that the first bit is received
		tabsr=0x13;//starting timers.
		rx_array[0]=1;
		}
}

void fill(void){//function responsible for sampling the input port.
	for(cnt=1;cnt<=7;cnt++){
		while(!A4_done);//waiting for the subroutine.
			if(p6_1==0){
				rx_array[cnt]=1;
			}
			else{
				rx_array[cnt]=0;
			}
	A4_done=0;//reset the variable.
	}
	tabsr=0x00;
	A0A1A4_init();
}

void task_exec(void){//function to compare the received and expected patterns together
	for(cnt=0;cnt<=2;cnt++){//starting bits
		if(rx_array[cnt]!=st_bit[cnt])
			rx_ok=0;
	}
	for(cnt=6;cnt<=7;cnt++){//stop bits
		if(rx_array[cnt]!=sp_bit[cnt-6])
			rx_ok=0;
	}
	if(rx_ok==1){//no errors on the start and stop bits.
		if((rx_array[3]==1)&&(rx_array[4]==0)&&(rx_array[5]==1))
			SW2_p=1;
		else if((rx_array[3]==0)&&(rx_array[4]==1)&&(rx_array[5]==0))
			SW3_p=1;
		else if((rx_array[3]==1)&&(rx_array[4]==1)&&(rx_array[5]==0))
			SW4_p=1;
		else
		rx_ok=0;
	}
	if((rx_ok==1)&&(SW2_p==1)){//switch 2 is pressed.
		disp_ctrlw(LCD_CLEAR);
		disp_ctrlw(LCD_CLEAR);
		display(0,"SW2  IS ");
		display(1,"PRESSED ");
	}
	else if((rx_ok==1)&&(SW3_p==1)){//switch 3 is pressed.
		disp_ctrlw(LCD_CLEAR);
		disp_ctrlw(LCD_CLEAR);
		display(0,"SW3  IS ");
		display(1,"PRESSED ");
	}
	else if((rx_ok==1)&&(SW4_p==1)){//switch 4 is pressed.
		disp_ctrlw(LCD_CLEAR);
		disp_ctrlw(LCD_CLEAR);
		display(0,"SW4  IS ");
		display(1,"PRESSED ");
	}
	else{//display error message.
		disp_ctrlw(LCD_CLEAR);
		disp_ctrlw(LCD_CLEAR);
		display(0,"TX/RX   ");
		display(1,"FAILED  ");
	}
		LED_Y=1;
	do{//waite for a period of time to solve the oversaturated problem.
		m=m+1;
	}while(m<=8000000);
	disp_ctrlw(LCD_CLEAR);
	disp_ctrlw(LCD_CLEAR);
	display(0,"Ready   ");
	}

#pragma INTERRUPT A4_isr
void A4_isr(void){//subroutine to set a varaible every 10 msec.
	A4_done=1;
}

void init_switches(void){//function to define switches as inputs.
	pd10_5=pd10_6=pd10_7=0;
}

void init_LEDs(void){//LEDs as outputs.
	pd7_0=pd7_1=pd7_2=1;
}

void main(void){//main function to call other functions.
	init_disp();
	display(0,message[0]);
	display(1,message[1]);
	init_switches();
	init_LEDs();
	A0A1A4_init();
	P6_1_init();
	ALL_LED_OFF
	while(1){
		while(!det){
			det_first();
			LED_Y=0;
		}
	fill();
	task_exec();
	det=0;
	rx_ok=1;
	SW2_p=0;
	SW3_p=0;
	SW4_p=0;
	m=0;
	cnt=0;
	}
}