Transmit Character Through UART

In this tutorial I am going to show you how to transmit a character through UART. First of all we have to initialize the UART circuitry of our micro-controller by providing proper values to the UART registers in AVR. There are basically 5 registers for UART....
(these codes have been written for ATmega128 micro-controller which has two UART circuitry, UART0 & UART1, the same code can be used with other AVR micro-controllers with some minor changes)

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Transmit a Character Through UART

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//Include AVR Header file

 #include < avr/io.h >
 

//Initialize UART circuitry
void UART1_Init()
{
     //set the baud rate as 9600 bits per second
     UBRR1H = 0x00;
     UBRR1L = 0x67;     //or 103 in decimal
     
     //set character size as 8-bit, no parity bit, one stop bit 
     UCSR1C = 0x06     // (1 << UCSZ1)|(1 << UCSZ0);
     
     //enable reception and transmission
     UCSR1B = 0x18     // (1 << RXEN)|(1 << TXEN);

} 

//Start main function
void main()
{   

     UART1_Init();
     
     //put the desired character in UDR register
     UDR1 = '@';

     //wait for the transmission to be completed
     while(! (UCSR1A & (1 << UDRE)));
}

Posted in: AVR, Tutorials, UART