wiegand_thief.c

/*
 * wiegand_thief.c
 *
 */ 
#define F_CPU 16000000UL

#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdlib.h>
#include <stdio.h>
#include <util/delay.h>

#define MAX_BUFLEN 255
#define BAUD 9600 // define baud
#define BAUDRATE ((F_CPU)/(BAUD*16UL)-1) // set baud rate value for UBRR
 
 // function to initialize UART
 void uart_init (void)
 {
	 UBRR0H = (BAUDRATE>>8); // shift the register right by 8 bits
	 UBRR0L = BAUDRATE; // set baud rate
	 UCSR0B|= (1<<TXEN0)|(1<<RXEN0); // enable receiver and transmitter
	 UCSR0C = (3<<UCSZ00);
 }
 
 int uart_transmit(char data  )
 {
	 while (!( UCSR0A & (1<<UDRE0))); // wait while register is free
	 UDR0 = data; // load data in the register
	 return 0;
 }
 
 unsigned char uart_receive( void )
 {
	 while ( !(UCSR0A & (1<<RXC0)) );
	 return UDR0;
 }

int main(void)
{
	uint8_t buf[255];
	uint8_t buflen = 0;
	uint8_t in_c = 0;
	uint16_t idle_count = 0;
	DDRC &= ~((1<<0)|(1<<1));
	DDRB |= (1<<5);
		
	uart_init();
	FILE mystdio = FDEV_SETUP_STREAM(uart_transmit, uart_receive, _FDEV_SETUP_RW);
	    
	stdout = &mystdio;
	stdin = &mystdio;
	
	_delay_ms(500);
	PORTB |= (1 << 5);
	_delay_ms(500);
	PORTB &= ~(1 << 5);
	
	printf("r");

    while (1) 
	{
		in_c = PINC & 0b11;
		if(in_c == 0b10)
		{
			buf[buflen++] = 0;
			while(1)
			{
				in_c = PINC & 0b11;
				if(in_c == 0b11)
				{
					break;
				}
				idle_count = 0;
			}
		}
		else if(in_c == 0b01)
		{
			buf[buflen++] = 1;
			while(1)
			{
				in_c = PINC & 0b11;
				if(in_c == 0b11)
				{
					break;
				}
				idle_count = 0;
			}
		}
		if(buflen != 0)
		{
			idle_count += 1;
		}
		if(idle_count == 0xFFFF && buflen != 0)
		{
			PORTB |= (1 << 5);
			_delay_ms(500);
			PORTB &= ~(1 << 5);
			printf("c");
			int i = 0;
			for(i = 0;i < buflen;i++)
			{
				printf("%d",buf[i]);
			}
			printf("r");
			idle_count = 0;
			buflen = 0;
		}
    }
}