Assembly Code Example(1)
USART_Init:
; Set baud rate
out UBRRH, r17
out UBRRL, r16
; Enable Receiver and Transmitter
ldi r16, (1<<RXEN)|(1<<TXEN)
out UCSRB,r16
; Set frame format: 8data, 2stop bit
ldi r16, (1<<URSEL)|(1<<USBS)|(3<<UCSZ0)
out UCSRC,r16
ret
C Code Example(1)
void USART_Init( unsigned int baud )
{
/* Set baud rate */
UBRRH = (unsigned char)(baud>>8);
UBRRL = (unsigned char)baud;
/* Enable Receiver and Transmitter */
UCSRB = (1<<RXEN)|(1<<TXEN);
/* Set frame format: 8data, 2stop bit */
UCSRC = (1<<URSEL)|(1<<USBS)|(3<<UCSZ0);
}
Note:
1. The example codes assume that the part specific header file is included.
More advanced initialization routines can be made that include frame format as parame-
ters, disable interrupts and so on. However, many applications use a fixed setting of the
Baud and Control Registers, and for these types of applications the initialization code
can be placed directly in the main routine, or be combined with initialization code for
other I/O modules.
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ATmega8(L)
2486M–AVR–12/03
ATMEL [ ATMEL ]
