ATMEGA8L ATMEL [ATMEL Corporation], ATMEGA8L Datasheet - Page 153

• Manufacturer Part Number: ATMEGA8L
• Description: 8-bit AVR with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

USART Control and Status
Register C – UCSRC
2486M–AVR–12/03
TXB8 is the ninth data bit in the character to be transmitted when operating with serial
frames with nine data bits. Must be written before writing the low bits to UDR.
The UCSRC Register shares the same I/O location as the UBRRH Register. See the
“Accessing UBRRH/UCSRC Registers” on page 149 section which describes how to
access this register.
• Bit 7 – URSEL: Register Select
This bit selects between accessing the UCSRC or the UBRRH Register. It is read as
one when reading UCSRC. The URSEL must be one when writing the UCSRC.
• Bit 6 – UMSEL: USART Mode Select
This bit selects between Asynchronous and Synchronous mode of operation.
Table 55. UMSEL Bit Settings
Bit
Read/Write
Initial Value
UMSEL
0
1
URSEL
R/W
7
1
UMSEL
R/W
6
0
Mode
Asynchronous Operation
Synchronous Operation
UPM1
R/W
5
0
UPM0
R/W
4
0
USBS
R/W
3
0
UCSZ1
R/W
2
1
UCSZ0
ATmega8(L)
R/W
1
1
UCPOL
R/W
0
0
UCSRC
153