/* sonar.c */
#include "door.h"
#include "sonar.h"
#include "rf.h"

/* states and flags */
static unsigned char dist = 0;		// count the cycle before echo comes back
static unsigned int count = 0;		// counter
static bit run = 1;
static bit echo = 0;
char xdata *leda = 0x0f000;  // the FPGA is configured to memory map led to this address

/* fire sonar and do distance calculations;
   signals serialTask to do RF stuff when user
   is near by
*/
void Sonar_Task() {	
	/* interrupt settings */
	EA = 1;
	ET1 = 0;
	ES = 0;

	/* set timer */
	TMOD = 0x21;
	PCON = PCON | 0x80;
	TH1 = 249;
	TR1 = 1;

	/* Set up and enable Timer0 for a 1 millisecond timer   */
	TL0 = RELOAD_LO;	/* Load the timer high and low bytes        */
	TH0 = RELOAD_HI;
	TMOD = 0x21;		/* Timer1 & Timer0 as 16-bit timers         */
	TR0 = 1;			/* Start the timer 0             */
	ET0 = 1;			/* Enable the timer interrupt 0 (Page 55) */
	EX0 = 0;			/* Enable the external interrupt 0 */
	EA = 1;				/* Enable the global interrupt  */
	IT0 = 1;			/* Enable the TCON for falling edge trigger */
	T0 = 0;				/* T0 = P3.4 is connected to sonar INIT, pin 68 on the XS40 */
	count = 0;
	echo = 0;
	PT0 = 1;
	run = 1;
	while (run) {
	}
}/* end Sonar_Task */


/* called by Ext0 ISR in DETECTING_USER state */
void Sonar_Ext0_Handler() {		// pin 12
	echo = 1;
}/* end	Sonar_Ext0_Handler() */


/* called by Timer0 ISR in DETECTING_USER state */
void Sonar_Timer0_Handler() {
	TL0 = TL0 + RELOAD_LO ;   // Load the timer high and low bytes        
	TH0 = RELOAD_HI;
	count = count + 1;
	if((count >=0) && (count < 60))		// RESET
	{
		EX0 = 0;
		T0 = 0;			// init = 0
		dist = 0;
		echo = 0;
	}
	else if((count >= 60) && (count < 1060)) 	// logic high
	{
		*leda = 0x12;		// 1
		T0 = 1;				// init = 1	
		
		if(echo == 0) 
			dist = dist + 1;
		else						
		{
			ET0 = 0;				// disable timer0 interrupt	
			EX0 = 0;				// disable external interrupt
			IE = 0;					/***** Check here later ****/
			state = REQUESTING_ID;	// echo comes back, switch state
			run = 0;
			return;
		}
		if((dist < L_THERSHOLD) || (dist > H_THERSHOLD))
		{
			IE0 = 0;
			EX0 = 0;
		}
		else
			EX0 = 1;
	}
	else if((count >= 1060) && (count < 11060))		//logic low
	{
		*leda = 0x5D;		// 2
		T0 = 0;
	}
	else	
	{
		count = 0;
	}
} /* end Sonar_Timer0_Handler() */

/*
void print(char c)
{
	SBUF = c;
	while(TI == 0);
	TI = 0;
}

void putChar(unsigned char c) {
	unsigned char a = c/100;
	unsigned char b = c%100;
	unsigned char d = b/10;
	unsigned char e = b%10;
	print(a+48);
	print(d+48);
	print(e+48);
}
*/