AVRFreaks.net

#include <avr/io.h>
#include <avr/interrupt.h>
#include <inttypes.h>
#include <util/delay.h>
#include "myLCD.h"
// Defines
#define   BaudRate 9600
//#define UbrrValue ((F_CPU / (16ul * BaudRate)) -1)
#define UbrrValue 51

void loop();
int i = 0;
char ID;
char val = 0;
char code[6];
char checksum = 0;
char bytesread = 0;
char tempbyte = 0;
char USARTReadChar()
{
   // Wait until a data is available
   while(!(UCSRA & (1<<RXC)))
   {
      // Do nothing
   }

   // Now USART has got data
   return UDR;
}

void USARTWriteChar(char data)
{
   // Wait until transmitter is ready
   while(!(UCSRA & (1<<UDRE)))
   {
      // Do Nothing
   }

   UDR=data;
}

void USARTInit()
{
   // Set Baudrate
   UBRRL = UbrrValue;
   UBRRH = (UbrrValue>>8);
   
   // Set frame format
   // Asynch, 8n1

   UCSRC = (1<<URSEL) | (1<<UCSZ1) |  (1<<UCSZ0);

   // Enable TX/RD
   UCSRB = (1<<RXEN) | (1<<TXEN);
}

int main()
{
   init_LCD();
   clr_LCD();
   print_LCD("Tag ID");
   USARTInit();
   while(1){
      loop();
   }
}

void loop()
{
      val=USARTReadChar();
      if(val==2);
      bytesread=0;
      while(bytesread<12){
      val=USARTReadChar();
      if((val == 0x0D)||(val == 0x0A)||(val == 0x03)||(val == 0x02)){
      break;
      }
      if ((val >= '0') && (val <= '9')) {
         val = val - '0';
      }
      else if ((val >= 'A') && (val <= 'F')) {
         val = 10 + val - 'A';
      }

// Every two hex-digits, add byte to code:
if (bytesread & 1 == 1) {
// make some space for this hex-digit by
// shifting the previous hex-digit with 4 bits to the left:
code[bytesread >> 1] = (val | (tempbyte << 4));

if (bytesread >> 1 != 5) {                // If we’re at the checksum byte,
checksum ^= code[bytesread >> 1];       // Calculate the checksum… (XOR)
};
}
else
{
tempbyte = val;                           // Store the first hex digit first…
};

bytesread++;                                // ready to read next digit
}
if(bytesread==12){
print_LCD("5-byte code: ");
move_LCD(2,1);
for (i=0; i<5; i++) {
print_LCD(code[i]);
}
}
}

      if(val==2);
      bytesread=0;

if (a < b) {
  c = 1;
};
else {
  c = 2
}