Datasheet

180
2467X–AVR–06/11
ATmega128
The following code example shows a simple USART receive function based on polling
of the Receive Complete (RXC) flag. When using frames with less than eight bits the
most significant bits of the data read from the UDR will be masked to zero. The USART
has to be initialized before the function can be used.
Note: 1. See “About Code Examples” on page 8.
The function simply waits for data to be present in the receive buffer by checking the
RXC flag, before reading the buffer and returning the value.
Assembly Code Example
(1)
USART_Receive:
; Wait for data to be received
sbis UCSRA, RXC
rjmp USART_Receive
; Get and return received data from buffer
in r16, UDR
ret
C Code Example
(1)
unsigned char USART_Receive( void )
{
/* Wait for data to be received */
while ( !(UCSRA & (1<<RXC)) )
;
/* Get and return received data from buffer */
return UDR;
}