ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 201

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

20.11.5
9223B–AVR–09/11
UBRRnL and UBRRnH – USART Baud Rate Registers
• Bit 15:12 – Reserved
These bits are reserved for future use. For compatibility with future devices, these bit must be
written to zero when UBRRnH is written.
• Bit 11:0 – UBRR[11:0]: USART Baud Rate Register
This is a 12-bit register which contains the USART baud rate. The UBRRnH contains the four
most significant bits, and the UBRRnL contains the eight least significant bits of the USART
baud rate. Ongoing transmissions by the Transmitter and Receiver will be corrupted if the
baud rate is changed. Writing UBRRnL will trigger an immediate update of the baud rate
prescaler.
Bit
Read/Write
Initial Value
Atmel ATmega48PA/88PA/168PA [Preliminary]
R/W
15
R
–
7
0
0
R/W
14
R
–
6
0
0
R/W
13
R
–
5
0
0
R/W
12
R
–
4
0
0
UBRRn[7:0]
R/W
R/W
11
3
0
0
R/W
R/W
10
UBRRn[11:8]
2
0
0
R/W
R/W
9
1
0
0
R/W
R/W
8
0
0
0
UBRRnH
UBRRnL
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