#include <delay.h>
#include <mega16.h>   
#include <stdio.h>           

#include "atm_i2c.h"


#define IR_CLOCK_HIGH 10  //time in usec, got these number from a code example
#define IR_CLOCK_LOW 100  //time in usec
                
#define clockfreq 14745600 //clock freq          
#define baud 9600 //UART BAUD
   
#define SEND_REQ 100                 
        
//#define DEBUG        
                
//clock is 14.7456 MHz, and timer is 14.7456MHz/256 = 57600Hz
//this is one timer inc every 1.736e-5 seconds, set counter
//to 256-58=198 to give an interrupt approx every 1 msec

//we want a separate interrupt event every 1 second, writing to the UART
//count 500 interrupts for half second.
#ifdef DEBUG
unsigned int uart_counts=500; 
int time = 0; 
#endif

//every 100ms we want to check the IR data   
unsigned int IRstart_counts=100; 
//need to hold IR vin low for more than 70ms
unsigned int IRlow_counts=71;  

//unsigned int IR_raw_read_1=0,  IR_good_read_1=0,IR_raw_read_2=0,  IR_good_read_2=0,
//		IR_raw_read_3=0,  IR_good_read_3=0;         

unsigned int IR_raw_read[3]={0,0,0},  IR_good_read[3]={0,0,0};         
   
                                       
//from atm_i2c.c
extern char TWI_state;    
extern char TWI_recv_buf[TWI_RECV_BUFSIZE];
extern  char TWI_send_buf[TWI_SEND_BUFSIZE];   
				
void IR_get_bits(int bitnum)             
{		                         
	//I don't think these delay functions halt interrupts
 	PORTA =  0x15;	//bring bits high again       	
    	delay_us(IR_CLOCK_HIGH);   //sleep .2 msec
    	PORTA =  0x00;	//bring bits low again   
    	delay_us(IR_CLOCK_LOW);   //sleep .2 msec        
        IR_raw_read[0] += ((PINA&0x02)!=0)<<bitnum;     
        IR_raw_read[1] += ((PINA&0x08)!=0)<<bitnum;   
        IR_raw_read[2] += ((PINA&0x20)!=0)<<bitnum;   
        		
}
		
//timer 0 ISR
interrupt [TIM0_OVF] void tim0_isr()
{         
   TCNT0=198;  //need to reset it after every interrupt, duh  	          

	if (0==IRstart_counts-- ) //bring IR vin low
	{ 
		PORTA =  0x00;		//bring bits 2 low for 70ms
    	IRstart_counts=100;     	//reload IR start counter
        IRlow_counts=70;                    
        //load the IR low counter for 70 ms or until PINA bit 0 is high   
	}          
 
	if (IRlow_counts<60 ) //after a couple ms check if PINA_0 is 1, then IR is ready
	{  
    	if  (1==(PINA&0x01))
   		{
     	   IRlow_counts=0;
   		}   
 	}
	if (0==IRlow_counts-- ) //after 70ms, clock IRs to read data
	{	
		IR_raw_read[0]=0;  //zero to start with, we add each binary digit at a time 
		IR_raw_read[1]=0;
		IR_raw_read[2]=0;      
  
        IR_get_bits(7);
		IR_get_bits(6);
		IR_get_bits(5);
		IR_get_bits(4);
		IR_get_bits(3);
		IR_get_bits(2);
		IR_get_bits(1);
		IR_get_bits(0);                   
            
        PORTA =  0x15;	//bring bits high again      
        
    	IRlow_counts=10000000;   //load something stupid high, it will get set to 70 by IRstart
        
    	IR_good_read[0]= IR_raw_read[0];     
    	IR_good_read[1]= IR_raw_read[1];
    	IR_good_read[2]= IR_raw_read[2];
	}     
}

// 2 Wire bus interrupt service routine
interrupt [TWI] void twi_isr(void)
{        
	int rec_data=0;	
	twi_parse();    
#ifdef DEBUG 
   	printf("time:%d  state:%d\r", time++,TWI_state);  
 #endif     	  
  	
  	rec_data = *(int*)TWI_recv_buf;
   	if (( rec_data == SEND_REQ+1 )||( rec_data == SEND_REQ+2 ) ||( rec_data == SEND_REQ+3 ) ) 	
   	{ 
	   	TWI_send_buf[0] = IR_good_read[rec_data-SEND_REQ-1];  
 #ifdef DEBUG  		
 	   	printf("time:%d  msg:%d\r ", time,rec_data);   	   	
  	   	printf("   buf:%s \r",TWI_send_buf );                             
 #endif  	   	
	   	*TWI_recv_buf=NULL;     
	}
   	
}      



void main()
{
	// 2 Wire Bus initialization
	// Generate Acknowledge Pulse: Off
	// 2 Wire Bus Slave Address: 55h  shifted 1 bit ==0xAA
	// General Call Recognition: Off
	// Bit Rate: 388.042 kHz
	TWBR=0x0B;
	TWAR=0xAA;
    TWCR=0x05;    
    //need to set to 100kbits for now, and slave addr 0x55
    twi_init(100, 0x55);  
    
   //port A is IR_Sensors
   DDRA = 0x15; 	//bits 0,2,4, are output
   PORTA = 0x15;	//all outputs high for now
   
   TCCR0=0x15;	//set timer 0 for internal clock/256
   TCNT0=198;	//timer is loaded with this number every time, counts to 256 to 
   		//generate interrupt.
   TIMSK=0x01;	//unmask timer 0 interrupt
    
    //port C bits 6 and 7 control the LEDS	
   DDRC = 0xf0;	//all bits are outputs
   PORTC = 0x00;	//set bit 7 high.   
   
   
    #asm("sei")	//global interrupt enable
    
    #ifdef DEBUG         //set up the UART, turn this off in real build  
	// USART initialization
	// Communication Parameters: 8 Data, 1 Stop, No Parity   
	UCSRA=0x00;      // USART Receiver: Off
	UCSRB=0x08;	// USART Transmitter: On
	UCSRC=0x86;	// USART Mode: Asynchronous
	UBRRH=0x00;	// USART Baud rate: 9600
	UBRRL=0x5F;		       
   #endif	    


    while(1)
    {
 
    }
    
}