ATMEGA325-16AJ ATMEL [ATMEL Corporation], ATMEGA325-16AJ Datasheet - Page 162

• Manufacturer Part Number: ATMEGA325-16AJ
• Description: 8-bit Microcontroller with In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

162
ATmega325/3250/645/6450
and consequently the TXB8n, FEn, DORn and UPEn bits, which all are stored in the
FIFO, will change.
The following code example shows a simple USART receive function that handles both
nine bit characters and the status bits.
Note:
Assembly Code Example
C Code Example
USART_Receive:
USART_ReceiveNoError:
unsigned int USART_Receive( void )
{
}
; Wait for data to be received
sbis UCSR0A, RXC0
rjmp USART_Receive
; Get status and 9th bit, then data from buffer
in
in
in
; If error, return -1
andi r18,(1<<FE0)|(1<<DOR0)|(1<<UPE0)
breq USART_ReceiveNoError
ldi
ldi
; Filter the 9th bit, then return
lsr
andi r17, 0x01
ret
unsigned char status, resh, resl;
/* Wait for data to be received */
while ( !(UCSR0A & (1<<RXC0)) )
/* Get status and 9th bit, then data */
/* from buffer */
status = UCSR0A;
resh = UCSR0B;
resl = UDR0;
/* If error, return -1 */
if ( status & (1<<FE0)|(1<<DOR0)|(1<<UPE0) )
/* Filter the 9th bit, then return */
resh = (resh >> 1) & 0x01;
return ((resh << 8) | resl);
1. The example code assumes that the part specific header file is included.
return -1;
For I/O Registers located in extended I/O map, “IN”, “OUT”, “SBIS”, “SBIC”, “CBI”,
and “SBI” instructions must be replaced with instructions that allow access to
r18, UCSR0A
r17, UCSR0B
r16, UDR0
r17, HIGH(-1)
r16, LOW(-1)
r17
;
(1)
(1)
2570A–AVR–09/04