/*******************************************************
This program was created by the
CodeWizardAVR V3.04 Advanced
Automatic Program Generator
© Copyright 1998-2013 Pavel Haiduc, HP InfoTech s.r.l.
http://www.hpinfotech.com

Project : 
Version : 
Date    : 20.12.2015
Author  : 
Company : 
Comments: 


Chip type               : ATmega8
Program type            : Application
AVR Core Clock frequency: 8,000000 MHz
Memory model            : Small
External RAM size       : 0
Data Stack size         : 256
*******************************************************/

#include <mega8.h>

//Definitions
#define LED_Green PORTD.5
#define RO PIND.7
#define RE PORTD.6
#define DE PORTB.7
#define DI PORTB.6

#define PIR PIND.4

#define CRC_POLYNOMIAL 0x31
#define TX_RATE 1
#define PACKET_LENGTH 10

#define TIMER_2 0x05

#define TIME_ON 10

// Declare your global variables here

unsigned char led_green_status = 0;
eeprom unsigned char my_address @0x00;

unsigned char rs485_rx[PACKET_LENGTH];
unsigned char rs485_tx[PACKET_LENGTH];

unsigned char rx_data[PACKET_LENGTH - 6];
unsigned char rx_length = 0;
unsigned char rx_type;

unsigned char tx_data[PACKET_LENGTH - 6];

unsigned char i;
unsigned char x;
unsigned char y;

unsigned char remainder;

unsigned char tx_byte = 0;
unsigned char tx_bit = 0;
unsigned char tx_status = 0;
unsigned char tx_clock = 1;

unsigned char rx_count = 0;
unsigned char rx_counter = 0;
unsigned char rx_rate = 0;
unsigned char rx_byte = 0;
unsigned char rx_bit = 0;
unsigned char rx_offset = 0;

unsigned char pir_status = 0;

void led_green_ref(){
    
    if(led_green_status){

        LED_Green = 1;
        led_green_status = (led_green_status & 0b11111000) | ((led_green_status & 0b00000111) - 1);
        
        if((led_green_status & 0b00111111) == 0){

            led_green_status = 0;
            LED_Green = 0;
        }
        else{
            
            if((led_green_status & 0b00000111) == 0){

                led_green_status = led_green_status | ((led_green_status >> 3) & 0b00000111);
                
                if(led_green_status & 0b10000000){
                
                    led_green_status = led_green_status & 0b01111111;
                    LED_Green = 0;
                }
                else{

                    led_green_status = led_green_status | 0b10000000;
                    LED_Green = 1;
                }                
            }
        }
    }
}

void led_green_flash(unsigned int delay){

    delay = (delay / 100) & 0b00000111;
    delay++;
    led_green_status = delay;
}

void led_green_blink(unsigned int delay){

    delay = (delay / 100) & 0b00000111;
    delay++;
    led_green_status = (1 << 7) |  delay << 3 | delay;
}

unsigned char crc(unsigned char const data_crc[], unsigned char length){

    remainder = 0;
    
    for(x = 0; x < length; x++){

        remainder ^= data_crc[x];
        
        for(y = 8; y > 0; y--){
            
            if(remainder & 0x80){
                
                remainder = (remainder << 1) ^ CRC_POLYNOMIAL;
            }
            else{

                remainder = (remainder << 1);
            }
        }        
        
    }
    
    return (remainder);
        
}

void send_rs485(unsigned char dest_address, unsigned char tx_type, unsigned char *data, unsigned char data_length){

    if(tx_status == 0){

        rs485_tx[0] = 0b01010101;
        rs485_tx[1] = my_address;
        rs485_tx[2] = dest_address;
        rs485_tx[3] = tx_type;
        rs485_tx[4] = 6 + data_length;

        for(i = 0; i < data_length; i++){

            rs485_tx[i + 5] = data[i];
        }
        
        rs485_tx[data_length + 5] = crc(rs485_tx, data_length + 5);

        tx_byte = 0;
        tx_bit = 7;
        tx_status = 1;
    }   
}

void collision_detect(){

    if(RO != DI){

        tx_status = 1;
        tx_clock = 1;
        tx_bit = 7;
        tx_byte = 0;
        DE = 0;
    }        
}

void tx_ref(){

    if((tx_clock == 1) && tx_status){        

        if((tx_status & 0b00000010) && (tx_byte < rs485_tx[4])){

            DE = 1;
            DI = (rs485_tx[tx_byte] >> tx_bit) & 1;
            
            
            
            tx_clock = TX_RATE;

            if(tx_bit == 0){
             
                tx_bit = 7;
                tx_byte++;
            }
            else{

                tx_bit--;
            }

            collision_detect();  
        }
        else{

            if((tx_status & 0b00000001) && ((tx_status & 0b00000010) == 0) && (rx_count == 0)){

                tx_status ^= 0b00000010;                 
            }
            else{

                if(tx_byte == rs485_tx[4]){

                    tx_status = 0;
                    tx_clock = 1;
                    tx_bit = 7;
                    tx_byte = 0;
                    DE = 0;
                }
            }
        }        
        
    }
    else{

        tx_clock--;
    }  
}

void packet_rx(){

    led_green_flash(100);        
}

void rx_ref(){

    if((tx_status & 0b00000010) == 0){

        if(rx_byte < PACKET_LENGTH){

            if(rs485_rx[0] == 0){

                if(RO == 0){

                    rx_count++;
                }
                else{
                    
                    if(rx_count){
                        
                        for(i = 1; i < PACKET_LENGTH; i++){

                            rs485_rx[i] = 0;
                        }
                        
                        rs485_rx[rx_byte] |= 0b01000000;
                        rx_bit = 5;
                        rx_counter = 1;
                        rx_offset = rx_count / 2;
                    }
                }
            }
            else{

                if(rx_counter){            

                    if(rx_counter == (rx_count + rx_offset)){                    

                        rx_counter = rx_offset;
                        
                        if(RO){
                            
                            switch(rx_bit){
                                
                                case 0:
                                    rs485_rx[rx_byte] |= 0b00000001;
                                    break;
                                case 1:
                                    rs485_rx[rx_byte] |= 0b00000010;
                                    break;
                                case 2:
                                    rs485_rx[rx_byte] |= 0b00000100;
                                    break;
                                case 3:
                                    rs485_rx[rx_byte] |= 0b00001000;
                                    break;
                                case 4:
                                    rs485_rx[rx_byte] |= 0b00010000;
                                    break;
                                case 5:
                                    rs485_rx[rx_byte] |= 0b00100000;
                                    break;
                                case 6:
                                    rs485_rx[rx_byte] |= 0b01000000;
                                    break;
                                case 7:
                                    rs485_rx[rx_byte] |= 0b10000000;
                                    break;                                    
                            }
                        }


                        if(rx_bit == 0){

                            rx_bit = 7;
                            rx_byte++;
                                           
                        }
                        else{

                            rx_bit--;
                        }
                    }
                    rx_counter++;                    
                }                
            }
        }
        else{

            if(crc(rs485_rx, rs485_rx[4]) == 0){

                rx_type = rs485_rx[3];              

                for(i = 0; i < (rs485_rx[4] - 6); i++){

                    rx_data[i] = rs485_rx[i + 5];
                }
                packet_rx();
            }
            
            rs485_rx[0] = 0;
            rx_count = 0;
            rx_counter = 0;
            rx_byte = 0;
        }
    }    
}

void pir_ref(){

    if(PIR){

        if(pir_status == 0){

            pir_status = 1;

            send_rs485(0xAA, TIME_ON, 0, 0); 

        }
    }
    else{

        pir_status = 0;
    }

}

// External Interrupt 0 service routine     Button 1
interrupt [EXT_INT0] void ext_int0_isr(void)
{
// Place your code here

    send_rs485(0, 0xAA, 0, 0);

}

// Timer1 overflow interrupt service routine        100 ms
interrupt [TIM1_OVF] void timer1_ovf_isr(void)
{
// Reinitialize Timer1 value
TCNT1H=0xCF2C >> 8;
TCNT1L=0xCF2C & 0xff;
// Place your code here

    led_green_ref();
    pir_ref();
    
}

// Timer2 overflow interrupt service routine        1 ms
interrupt [TIM2_OVF] void timer2_ovf_isr(void)
{
// Reinitialize Timer2 value
TCNT2=TIMER_2;
// Place your code here

    rx_ref();
    tx_ref();
}

void main(void)
{
// Declare your local variables here

// Input/Output Ports initialization
// Port B initialization
// Function: Bit7=Out Bit6=Out Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 
DDRB=(1<<DDB7) | (1<<DDB6) | (0<<DDB5) | (0<<DDB4) | (0<<DDB3) | (0<<DDB2) | (0<<DDB1) | (0<<DDB0);
// State: Bit7=0 Bit6=0 Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 
PORTB=(0<<PORTB7) | (0<<PORTB6) | (0<<PORTB5) | (0<<PORTB4) | (0<<PORTB3) | (0<<PORTB2) | (0<<PORTB1) | (0<<PORTB0);

// Port C initialization
// Function: Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 
DDRC=(0<<DDC6) | (0<<DDC5) | (0<<DDC4) | (0<<DDC3) | (0<<DDC2) | (0<<DDC1) | (0<<DDC0);
// State: Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 
PORTC=(0<<PORTC6) | (0<<PORTC5) | (0<<PORTC4) | (0<<PORTC3) | (0<<PORTC2) | (0<<PORTC1) | (0<<PORTC0);

// Port D initialization
// Function: Bit7=In Bit6=Out Bit5=Out Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 
DDRD=(0<<DDD7) | (1<<DDD6) | (1<<DDD5) | (0<<DDD4) | (0<<DDD3) | (0<<DDD2) | (0<<DDD1) | (0<<DDD0);
// State: Bit7=T Bit6=0 Bit5=0 Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 
PORTD=(0<<PORTD7) | (0<<PORTD6) | (0<<PORTD5) | (0<<PORTD4) | (0<<PORTD3) | (0<<PORTD2) | (0<<PORTD1) | (0<<PORTD0);

// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: Timer 0 Stopped
TCCR0=(0<<CS02) | (0<<CS01) | (0<<CS00);
TCNT0=0x00;

// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: 125,000 kHz
// Mode: Normal top=0xFFFF
// OC1A output: Disconnected
// OC1B output: Disconnected
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer Period: 0,1 s
// Timer1 Overflow Interrupt: On
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
TCCR1A=(0<<COM1A1) | (0<<COM1A0) | (0<<COM1B1) | (0<<COM1B0) | (0<<WGM11) | (0<<WGM10);
TCCR1B=(0<<ICNC1) | (0<<ICES1) | (0<<WGM13) | (0<<WGM12) | (0<<CS12) | (1<<CS11) | (1<<CS10);
TCNT1H=0xCF;
TCNT1L=0x2C;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0x00;

// Timer/Counter 2 initialization
// Clock source: System Clock
// Clock value: 250,000 kHz
// Mode: Normal top=0xFF
// OC2 output: Disconnected
// Timer Period: 1 ms
ASSR=0<<AS2;
TCCR2=(0<<PWM2) | (0<<COM21) | (0<<COM20) | (0<<CTC2) | (0<<CS22) | (1<<CS21) | (1<<CS20);
TCNT2=TIMER_2;
OCR2=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=(0<<OCIE2) | (1<<TOIE2) | (0<<TICIE1) | (0<<OCIE1A) | (0<<OCIE1B) | (1<<TOIE1) | (0<<TOIE0);

// External Interrupt(s) initialization
// INT0: On
// INT0 Mode: Falling Edge
// INT1: Off
GICR|=(0<<INT1) | (1<<INT0);
MCUCR=(0<<ISC11) | (0<<ISC10) | (1<<ISC01) | (0<<ISC00);
GIFR=(0<<INTF1) | (1<<INTF0);

// USART initialization
// USART disabled
UCSRB=(0<<RXCIE) | (0<<TXCIE) | (0<<UDRIE) | (0<<RXEN) | (0<<TXEN) | (0<<UCSZ2) | (0<<RXB8) | (0<<TXB8);

// Analog Comparator initialization
// Analog Comparator: Off
// The Analog Comparator's positive input is
// connected to the AIN0 pin
// The Analog Comparator's negative input is
// connected to the AIN1 pin
ACSR=(1<<ACD) | (0<<ACBG) | (0<<ACO) | (0<<ACI) | (0<<ACIE) | (0<<ACIC) | (0<<ACIS1) | (0<<ACIS0);
SFIOR=(0<<ACME);

// ADC initialization
// ADC disabled
ADCSRA=(0<<ADEN) | (0<<ADSC) | (0<<ADFR) | (0<<ADIF) | (0<<ADIE) | (0<<ADPS2) | (0<<ADPS1) | (0<<ADPS0);

// SPI initialization
// SPI disabled
SPCR=(0<<SPIE) | (0<<SPE) | (0<<DORD) | (0<<MSTR) | (0<<CPOL) | (0<<CPHA) | (0<<SPR1) | (0<<SPR0);

// TWI initialization
// TWI disabled
TWCR=(0<<TWEA) | (0<<TWSTA) | (0<<TWSTO) | (0<<TWEN) | (0<<TWIE);

// Global enable interrupts
#asm("sei")

while (1)
      {
      // Place your code here
      }
}