RS232 settings in Atmega16/32

Steps for RS232 communication using Atmega16 and VB.net application

1. Set Baud Rate
#define F_CPU 8000000L
#define USART_BAUDRATE 9600
#define BAUD_PRESCALE (((F_CPU / (USART_BAUDRATE * 16UL))) - 1)

2. Register Setting
   UCSRB |= (1 << RXEN) | (1 << TXEN);   // Turn on the transmission and reception circuitry
   UCSRC |= (1 << URSEL) | (1 << UCSZ0) | (1 << UCSZ1); // Use 8-bit character sizes

   UBRRH = (BAUD_PRESCALE >> 8); // Load upper 8-bits of the baud rate value into the high byte of the UBRR register
   UBRRL = BAUD_PRESCALE; // Load lower 8-bits of the baud rate value into the low byte of the UBRR register

   UCSRB |= (1 << RXCIE); // Enable the USART Recieve Complete interrupt (USART_RXC)

3. Interrupt Routine
// this will echo back the same char
ISR(USART_RXC_vect) {
  char R;
   R = UDR;
  UDR =  R;
}


4. sei();

5.  main()
and infinite loop