AVR Freaks

#define BIT(n) (1 << (n))

void setup_uart(void)
{
	UBRR = 23;
	UCSRB |= BIT(TXEN);
	return;
}

void send_character (unsigned char c)
{
	while ( (UCSRA & BIT (UDRE) ) == 0 ); // Something looks amiss here.  Check my code below.
	UDR = c;
	while ( (UCSRA & BIT (TXC) ) == 0); // This isn't needed, as you check UDRE this upon entry - which is the correct place to check.
}

int main(void)
{
	setup_uart();
	while (1){
	 send_character('U');
	}	 
}

// ImageCraft ICC-AVR C compiler V7.xx
// Target micro-controller: Mega32
// Crystal: 16.0000Mhz

#include 
#include 

// UART0 initialize
// Desired baud rate = 9600
// Actual baud rate = 9615
// % Error = 100 - ((9600 / 9615) * 100) =  0.156%
// No Parity, 8 bits, 1 Stop bit: (N-8-1)
void uart0_init(void) {
     UCSRB = NULL; // Disable while setting baud rate
     UCSRA = NULL;
     UCSRC = (1<<URSEL) | (1<<UCSZ1) | (1<<UCSZ0); // Select 8 bit data
     UBRR = 0x0067; // Set baud rate lo: 9600 BAUD
     UCSRB = (1<<TXEN); // Enable USART transmitter
}

/* Using the ImageCraft ICC-AVR compiler, putchar()
   must be defined be the user.  This allows the
   user to use all of the features of stdio.h and
   select the USART or other output hardware, such
   as an HD44780 text based LCD display.
*/
void putchar(char c) {
     // Wait for empty transmit buffer
     while ( !(UCSRA & (1<<UDRE)) ) // Note the way '!' UDRE is checked...               
     ;
     UDR = c; // Putting data into buffer , sends the data
}

void main(void) {
     uart0_init();

     while(1) printf("Hello world!\n");
}